Today’s society thrives on instant gratification but building an engine is an exacting process that must not be rushed. Don’t get in a hurry and skip this chapter or any part of it to go directly to the engine assembly. The fact that your engine parts are back from the machine shop, does not mean that the machine shop perfectly performed all the work or everything was done correctly. They are human, after all, and you have to ensure that everything is done correctly at each stage of the project.
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You’ve probably purchased all the parts you need to complete your engine. If you are building a performance engine that will most likely require special-length pushrods and specific valvesprings, you will buy those later, when you get the proper measurements. If you are building a basically stock engine you should have all your parts by now. Since you are assembling the engine yourself, you are taking responsibility for how it turns out. If you skip a step or forget something, your machine shop is not going to warranty anything for you. This fact makes the pre-assembly inspection one of the very important steps along the way. It’s the last of the checks and balances before actual assembly. You can’t assume everyone else along the way has done his or her job correctly. If your engine runs for five minutes and throws a rod out the side of the block, you are solely responsible for not double checking the parts. Accepting your role, you can then call the machine shop and have them assemble your engine for you; or, you can proceed with caution and have a long-lasting sense of accomplishment from successfully building your own engine. There’s a high probability that if you follow along with all these steps, confirm that all the parts and clearances are correct, and assemble your engine as instructed, it will run well and will do so for a long time.
Take a few minutes to make sure you have everything you need for pre-assembly. The following are lists of parts, tools, and chemicals that you should gather and use. If you have a workbench, make some space on it for building an engine. If you don’t have a bench, find a way to make a strong and level horizontal surface near your engine, so you can keep your supplies and parts clean and close by. Cleanliness during the pre-assembly is just as important as it is during final assembly.
Check that you have all your parts close by and in boxes, plastic bags, or protected in some way from the elements and the environment. Most of the parts needed for final assembly will be needed for the preassembly steps.
You will need your block (on a stand), cylinder heads (and their components), crankshaft, connecting rods, pistons, camshaft, lifters, timing chain set, fasteners, intake manifold, head gaskets, intake manifold gasket, oil pan, pan gasket, oil pump, oil pump pickup, oil pump drive-shaft, and bearings.
Tools Equip yourself with these common assembly tools:
• Torque Wrench; lots of fasteners and components will be torqued in this chapter. This is where we check to make sure the machine shop did all the work correctly.
• Plastigage; this handy tool is easy to use, and it’s going to possibly save your engine from disaster.
•Rod Bolt Protectors; not everyone plans on building more than one engine in their life, so purchasing some rod bolt protectors or making some out of some 3/8- inch fuel hose is a cost-effective solution to protecting the crankshaft during this engine build.
• Rod Guide; after building engines with and without a rod guide, I prefer using a rod guide rather than rod bolt protectors. It allows you a little more insurance that you won’t damage the crankshaft journals during assembly.
• Dial Indicator; you will be using this to check critical clearances.
• Cam Degree Wheel; if you don’t have access to a cam degree kit, you can get by with a cam degree wheel, a dial indicator, and a set of valve-checking springs, which mimic the valve springs but won’t apply too much pressure on the lifters during pre-assembly checking. You’ll use this to degree the cam for optimum performance.
• Soft Bench Vise Jaws; I guess this assumes that you have a bench vise. Hopefully you do. You can purchase soft jaws that are made for a vise or you can get a few pieces of 1/8-inch sheet aluminum and bend it over the jaws of your vise to make a set of soft jaws yourself.
In order to check all the work done by your machine shop and the factory that produced your parts, you’re going to need some precision measuring tools. You also need the tools to confirm that your combination of parts will work with each other. The tools will be used to check journal sizes, bearing clearances, bore sizes, piston clearances, cam timing, valvetrain clearances as well as function, and more.
The measurements to be taken during pre-assembly are measured in the thousandths. I’m talking about measuring parts and being precise to 1/1,000 (.001) inch, where 1/8 inch is .0125 inch. If you’ve never measured anything that a tape measure wasn’t precise enough for, then you are in for a change of pace. The tools you use in this chapter need to be precision instruments and the more precise they are, the more they cost. Some of the ones you need for this chapter include tools that you may never use again. If you believe this is the case, you have a few options on how to approach the requirements of this chapter.
Read through all the steps and decide which tools you can justify purchasing and which ones you can’t. Borrow them from friends or rent the tools you aren’t going to buy. Pay your machine shop to perform specific measurements you won’t have the ones for and check the clearances you will be able to make. One tool used in the following chapter in particular is a dial bore gauge. If you have your machine shop check the main- and connecting-rod bearing bores and the sizing of your bearings, you can double check their work with the Plastigage steps. The shop can also confirm the size of your cylinder bores as an extra service, and then you can double check piston wall clearance with feeler gauges.
Don’t forget that relying on a shop to perform every clearance test does not mean they take any responsibility if something is wrong after you assemble the engine. After you take the engine parts from a shop, you are responsible for anything that goes wrong. You should always double check a technician’s work on bearing clearance surfaces with Plastigage. If a bearing fails they have no reason to warranty an engine because they don’t know if you torqued the bolt correctly.
When going through this chapter, there are many important steps, but not every step may pertain to your application. Take into consideration what the steps are asking you to perform because you could be mixing aftermarket and factory parts that may not work well together. If you’re building a completely stock engine with stock pistons and a stock camshaft, you may skip the step of checking the piston-to-valve clearance. Good engine builders trying to get the best performance out of an engine will dial-in every performance cam. If you are building an engine with a stock cam, you can take the chance and skip the degree process, but you’re better off checking it anyway. If you’re new to engines, the degree process will give you more insight into camshaft dynamics. There’s nothing wrong with learning more about an engine.
Instead of skipping steps requiring a dial bore gauge because you don’t have access to one, you can get a less-expensive snap gauge used for the task. These are less accurate because you have to check the bore with a less-accurate snap gauge and then transfer the reading to an outside micrometer or a caliper. Every precision tool has accuracy rated to plus or minus a small margin of error. Each time you transfer a reading from one tool to another you may be “stacking” those margins and end up being off by more than you think. The snap gauge is a viable alternative to checking bore sizes with a bore gauge because you have the backup checks as insurance.
I can’t stress enough that as soon as you turn a wrench on building your engine, the responsibility is yours. So if you want to be sure everything turns out great, you should follow the steps even if they don’t apply to you. You can ask your machine shop if you can skip a specific step but if there’s any reservation it’s better to not skip it; it’s better to be safe than sorry.
You’re not sealing anything yet, at this inventory stage, but you need lubricants for coating components so you can check clearances without damaging parts. You need a handheld squirt can filled with 30W nonsynthetic oil and a bottle of Royal Purple Max-Tuff Assembly Lube.
You’re going to need a good supply of paper shop towels to clean and wipe parts as you work through this chapter. As stressed in Chapter 2 (Tools), don’t use regular towels for cleaning. A regular towel can leave threads from the fabric behind that don’t break down in the oil and can cause bearing damage. The paper fibers will break down in the oil. In order to clean up small amounts of oil and chemicals, cut the towels into smaller pieces instead of ripping them apart. This keeps paper fiber dust to a minimum.
Pull all the machined parts out of their boxes and wrappers and inspect them. If you’ve followed along with this whole book, you’ve already done some of these inspections. Do them again because these parts may have been out of your possession for a few days. Always inspect your parts before assembly.
Start with the block. Look at all the machined surfaces and make sure they are smooth. The deck should be free of nicks and dings. Pull out your straight edge and move it across the head mating surface with a .002-inch feeler gauge and make sure the surface is machined flat. Inspect the lifter bores by carefully using your finger to check for burrs that may interfere with the life of the lifters. The machined surface on the front of the block behind the camshaft sprocket should be smooth and flat. Peer into the camshaft journals and make sure all bearings appear to be installed and in good shape. Turn the block over and inspect the cam bearings with a light touch of a finger to be sure there are no gouges or burrs on them. Run your fingers in the main bearing saddles and make sure there aren’t any burrs. Visually inspect the bearing caps for nicks or evidence that they had been dropped or damaged. The mating surfaces between the block and the main caps should be flat and in good shape so they do not distort the bearings when torqued into place.
The head gasket surface should be smooth and free of burrs. Check the heads as you did the block deck with a straight edge and feeler gauge to be sure they are flat. If the heads are already assembled, visually check all the parts of the head for defects. If the heads are not assembled, inspect the valve seats and guides for nicks. I’ve had heads given to me and been told they were ready to bolt on, but had a large gouge in the tip of a valve. It appeared as if the head had fallen against something solid. Missing a problem like this can lead to engine failure, or at least valvetrain failure.
Check the bearing surfaces on the crankshaft for nicks and dings. Inspect the threads in the front of the crank and on the rear flange for damage. The snout of the crank should be in good shape to ensure ease of installing the harmonic dampener.
Rods and pistons
The pistons should be checked to make sure the ring lands are in good shape, and that there aren’t any dents or dings on the faces or skirts that may cause premature engine failure or wear. The rods should be visually inspected for damage or imperfections. The sides of the bearing journals and bearing surfaces should be smooth and in good shape. Manufacturers and/or machine shops grind material off the rod bearing cap while attempting to balance them. I’ve seen loose metal barely hanging on the bottom of a connecting rod, after this process, which could have fallen off inside the engine after startup. Make sure there aren’t any issues like this on your connecting rods. If your rods had been numbered, make sure your rods and rod caps are correctly mated and that you have numbers one through eight. If you have two number sevens and no number five, there’s a problem. Make sure the pistons are correctly installed on the rods.
The Remaining Parts
Inspect all your other parts such as camshaft, lifters, bearings, and pushrods, for defects, too. If there were any problems with the parts the shop machined for you, contact them for resolution before using the parts. In some cases they can walk you through a quick repair. Everything needs to be correct to work right. Basically all the planets have to align between the intake manifold and the oil pan for your engine to work correctly.
Don’t forget to inspect each part for dirt and debris before assembly. A little dirt or a small piece of metal left in the engine during assembly can be catastrophic.
Every engine builder uses micrometers, feeler gauges, and Plastigage. Good engine builders do not rely on only one method of measuring bearing tolerances while building an engine. Use two methods to ensure your engine will be assembled correctly. The first method of checking the bearings, with a dial bore gauge and micrometer, ensures that you have the correct bearings to start with so you don’t go directly to the second step of using Plastigage and damage a perfectly good set of bearings.
When assembling an engine and installing a hydraulic camshaft, you will be faced with an extra task when performing checks on valve-topiston clearance and valve lift. Hydraulic lifters have a piston inside the body, which is pushed up by a spring (when the engine lacks oil pressure) and kept in the lifter with a retaining clip. That piston has a cup where the pushrod seats into it. While the engine is running, pressurized oil in the lifter keeps the piston pressed up against the retaining clip while the pushrod presses down against it. When performing checks using hydraulic lifters, they will be a little spongy since the engine won’t have oil pressure to firm up the lifter.
Professionals have two ways to solve this problem and get accurate valvetrain readings. One way is to find a solid lifter with the same pushrod cup height as the hydraulic lifter. The other way is to disassemble the lifter and replace the internal spring with washers or shims to restore proper cup height. Do this to two lifters specifically used for checking. Be extremely careful with the lifter face that rides on the camshaft and the outside cylinder of the lifter. Place the lifter on a nonmarring surface and gently push the piston down a little while carefully removing the retaining clip inside the lifter. Slowly release the pressure on the piston. Turn the lifter over and remove the piston and spring. In some cases, suction in the lifter keeps the internal piston in the lifter. With just a little force, push a paper clip down into the center of the lifter bleed hole to release suction on the small valve in the bottom of the lifter; too much force will damage the lifter. If you’re not able to get the lifter apart, contact your machine shop.
You need to keep note of how the lifter is installed so you can put it back in the same position from which you removed it. Stack washers or shims under the piston to mimic the original piston height in the lifter. A good gauge of the height is making sure the retaining clip is a tight fit when reinstalled. When you put the lifter back together, make sure you are careful with the face of it and that there isn’t any debris inside the lifter from the washers or the valve checking process. Debris means quick death to a lifter.
Clean Up Your Act
Every engine part you’ll be working with is a precisionmachined or manufactured part.
Take care while handling each part when pre-assembling it, checking it’s measurements, and storing it back in its container or box until it’s installed during final assembly. The parts should be kept clean as well as damage-free. If parts get dusty and dirty while being stored, that debris is going to end up in your engine. The area you designate for engine work should be a clean environment, so there shouldn’t be drafts that can blow debris into your work, or rafters above that can drop dirt into the engine. I realize not everyone hasa perfect area to build their engine but you need to be aware of your environment and cover your parts with clean plastic when you’re not working on them. If your garage or shop is damp, keep parts like the crankshaft and engine block lightly oiled with penetrating oil, such as WD40, to keep rust from forming. Keep boxed parts off of cold, damp floors with a moisture-proof barrier under them. If you find debris on a part during pre-assembly, clean the part right away to keep the matter from contaminating the engine.
Your machine shop should have spent the time it takes to get the guides, seats, seals, and valves in good working order. Any of this work should be preserved if you need to disassemble the head for any reason. This is a good reason to have a Goodson Cylinder Head Organizer. If you take a valve out of the head, make sure you put it back in the exact spot you pulled it from. You could have had the machine shop set the installed height on your valve springs too. If you did, it’s important to put them back in the position you pulled them from, as well as the retainers, keepers, and any shims that were installed under each spring. Keep them organized!
Hopefully, if you have press-ontype valve seals, your shop did not install valve seals while they were doing your head work. A few steps in this chapter require you to remove the valves. It’s important to know that the edge of the valve lock groove on the valve is sharp and usually damages the press-on valve seal during removal of the valve. These type valve seals should never be used once they have had a valve pulled through them. These seals are so delicate that they typically come with a special protector sleeve just to install them. Only install the valve seals when you are finished with this chapter. Talk to your machine shop if you have any questions about replacing the valve seals or if you don’t know if they have performed the valve seat checking and clearances covered in the following steps 2 through
Bearing clearances are different for different applications. Stock engines have tighter tolerances than performance engines.
These ring gap recommendations are for the 4.25-inch bore of a 454-ci engine. You can use the recommended ring gap factor to determine what ring gap you should be using for the bore of your engine, but the best solution to determining proper ring gap is to consult your machine shop or the paperwork accompanied with your ring set. You may notice that the intermediate (second) ring gap recommendations are larger than the top compression ring. After much testing, Perfect Circle has determined this method increases the stability of the top ring for a better seal. It increases horsepower gains in upper RPM ranges and reduces blow-by. The larger gap on the intermediate ring allows inter-ring pressure to escape past it, rather than lifting the top compression ring off the cylinder wall allowing even more pressure to squeeze by.
Step 1: Inspect Cylinder Head (Use Special Tool)
By this stage, your machine shop should have assembled the cylinder heads, with the exception of the press-on valve seals. If you remember my warning in the previous chapter, you recall that you need to inspect the heads, so the valve seals need to be removed. If you don’t have them removed, you cannot check valve-to-guide clearance and valve-stem seal concentricity. The heads should be disassembled for final inspection. The valves, retainers, locks, springs, and spring shims that come off the head should be kept in order so they can go back on in the same place. Make sure the valves and guides are free of any lubricant and slide them back in the guides so the valve sits about a 1/2 inch off the seat. Set up your dial indicator on the edge of the valve, try to move the valve up and down, and write the amount of movement on your worksheet. If you don’t have a dial indicator, you shouldn’t feel any wobble. The valve should not have more than .002 inch of play. Any more than that and a lot of oil will pass into the cylinder—causing excessive oil consumption; smoking out of the tail pipe; pressure on the valve seat, causing premature valve seat failure; and, in severe cases, overheating the valve until it breaks.
Step 2: Test Valveseat Seal
Most likely your machine shop used lapping compound to confirm the quality of the valve seats. Clean the seat and valve of possible leftover lapping compound. Apply a thin coat of layout dye to the valve faces and seats and let it dry. Use a lapping stick to press and turn the valve against the seat for about three seconds. Check the marks in the compound on the seat and valve to confirm there is a uniform pattern on both. Completely clean the dye and install the valves with light valve-checking springs and spark plugs, and set the head with valves facing up. Fill the combustion chamber with enough solvent to cover the valve faces. Using an inspection flashlight, peer into the ports and confirm there isn’t any solvent leaking past the valve seats. If there is, confirm the seats are clean and try again. A good-quality valve job won’t leak.
Step 3: Check Valve Guide Quality (Use Special Tool, Precision Measurement)
The valve guides must be concentric in order for the press-on valve-stem seals to work correctly. The seal should be centered over the top of the guide. Use your caliper to measure the thickness of each guide at twelve, three, six, and nine o’clock positions to confirm the seal concentricity to the guide. If the seal is not centered on the guide, the valve could be forced to the side of the guide (shown exaggerated in the left picture) and cause premature wear of the guide and the seal. Once you’ve confirmed the guides are correctly machined, clean the seat and valve for cylinder number-1 and slide them into their guides. If your valve-stem seals come with a protective cover that slides over the stem to protect the seal from getting damaged upon installation, put the cover on and carefully slide the seal over the stem without allowing the valve to slide out of the guide. Seat the seal all the way down on the guide.
Set up your dial indicator over the top of the tip of the stem and zero it with the valve pressed all the way up. Install the retainer and locks on the stem (without the spring) and move the valve down the exact amount of valve lift listed on your cam card (listed as “at valve”). Be sure you get the specs correct because “single-pattern” cams have matching lift at the intake and exhaust valve and “dual-pattern” cams have a different lift for intake and exhaust. Check the distance between the bottom of the retainer and the top of the valve-stem seal once the valve is down the correct “lift” amount. The clearance should be at least .070 inch. If it’s close, you’re going to need to check all the valves this way.
Step 4: Valvespring Checks (Precision Measurement)
Check every valvespring for its “installed height,” to confirm they all match and meet the requirements of the camshaft (specs listed on your cam card). Start by using a valvespringheight gauge installed on the valve with the locks and retainer. You can also get away with a snap gauge or caliper with less accuracy. Use any shims necessary to meet the installed height specified by the spring manufacturer. This gauge (second photo from left) is reading 1.9 inches and needs to be shimmed. There should be one thin, hardened, flat washer (or in some cases it’s a rotating washer) between the spring and the spring pocket in the head, to keep the spring from digging through the softer material. Additional shims may be necessary to get the correct installed height; they go under the hardened washer. Now move to your spring tester. They come in two styles: low-cost style for your bench vise, or expensive freestanding ram-type. To get an accurate reading, compress and relax the spring at least 10 times to allow it to stabilize. If you have more than single springs, compress all springs and use the retainer in the vise to keep the springs in place. Then compress the spring in the tester to match the spring height gauge. Write down the seat pressure on your worksheet, then check the springs to confirm their seat pressures match within + / -10% of requirements listed on your cam card. Repeat the installed height shimming and checking as well as seat pressure testing on each spring because these are different with each one. Lightly grind the spring with a cone (in the far right photo) if it’s a snug fit to the retainer or if the spring has sharp edges on the end of the windings.
Step 5: Check Compressed Spring Clearance (Precision Measurement)
After seat pressure has been confirmed you can check for “compressed spring clearance.” Calculate the compressed spring height by subtracting the maximum valve lift (on your cam card) from your installed height (taken from the spring installed height from the previous steps). If you are using anything other than standard rocker ratios, be sure to adjust your maximum valve lift accordingly. Then compress the spring in your bench vise just until the coils completely bind and measure this “stack” height and record it. If you have more than single springs, compress all springs and use the retainer in the vise to keep the springs in place. Last, subtract the stack height from the compressed height to get the compressed spring clearance, which for optimum reliability should be at least + .100 inch. Repeat this check on the rest of the springs.
Step 6: Check the Main Bore(Precision Measurement)
The block should be on a flat surface with the bottom facing upward to properly check the main bearing bore alignment. Use a precision straight edge and feeler gauges. If you are able to slide more than a .001-inch blade under the straight edge, the main bore needs to be machined.
Step 7: Seat Main Caps in Registers (Important!)
While installing the main caps in the following steps, make sure they are seated in the registers of the block before torquing the cap into its place. Failure to do so damages the cap and the register in the block.
Step 8: Main Bearing Orientation
Big-blocks have two different main bearing shells: grooved, and non-grooved. The grooved bearings go in the block saddles and the non-grooved bearings go in the main caps.
Step 9: Main Cap Orientation
The four front main caps have arrows and the letter “F” cast in them from the factory. The F designates front, so all the arrows should be pointing forward. If the machine shop installed the main caps backward, they may have performed the line bore or hone incorrectly. If that’s the case, the work must be redone. By now you or the machine shop should have numbered the four front caps “1” through “4.” The rear main cap is obvious and doesn’t need an arrow or to be numbered.
Step 10: Check Rod Bore
Before installing the rod and main bearings, check the bores to confirm they are machined correctly, to ensure the bearings are correct and have the right bearing crush. In order to check bore sizes, you need a dial bore gauge or a snap gauge (which isn’t as accurate) and a 2- to 3-inch outside micrometer to transfer snap gauge readings. These readings need to be done, so if you don’t have these tools you should have a professional check them for you. Clean the mating surfaces of the rods and mains. Lubricate the rod and main bolts to achieve the correct torque and clamping force. One at a time, put the connecting rods in the vise jaws with your soft jaws in place. Install the rod caps and take a reading with your dial bore gauge. Check bore taper from front to rear. Do this a few times on each rod to confirm accuracy. Record your findings.
Step 11: Check Main Journal Bore(Precision Measurement)
Install the main bearings in the proper location and in the correct direction. Make sure they are completely seated in their registers before applying torque. Torque them into place. Take the readings with your tools in the same manner as the rods. There should be no more than .0002-inch taper (from front to rear) and no more the .0007-inch out-of-round. If they are out of spec, you should call your machine shop to remedy the problem. When you have your measurements remove the main and rod caps. Standard production rod housing bore is 2.3247 to 2.3252 inches, standard production GM main bore is 2.9370 to 2.9380 inches.
Step 12: Rifle Brush Crankshaft
Before installing the crank with new bearings, you need to make a pass through the oil passages in the crankshaft with a rifle brush. If debris falls out of the crank during pre-assembly, you’ll damage the bearings.
Step 13: Check Crankshaft for Straightness(Precision Measurement)
The crank needs to be checked for straightness. Clean the front and rear main bearings and their saddles along with the main journals of the crankshaft with a clean and dry paper towel. Install the front and rear main bearings. Lubricate the crank side of the two bearings with some assembly lube. Carefully and gently place the crankshaft on the bearings. Using your adjustable stand, place the dial indicator on the top of the crankshaft’s number-3 main journal. Make sure the tip won’t fall into the oil hole on the crank while it’s being rotated. Slowly rotate the crank and take note of the runout on the dial indicator. A crankshaft should not have more than .0005-inch runout. The crank should be as close to zero as possible. Anything more and you‘re taking a chance of damaging your bearings. If your crank is not straight enough for your application, it’s time to straighten it or get a replacement unit. Before removing the crankshaft, check to make sure the runout on the damper and timing sprocket surfaces, as well as the rear main seal surfaces, is not more than .001 inch.
Step 14: Clean Bearings
Clean the main bearings, main caps, and main cap areas on the block with a clean and dry paper towel. Any lubricant or debris on the bearings throws off the readings. While doing that, go ahead and check these areas for nicks and burrs with your finger. For proper bearing installation see page 88.
Step 15: Install Main Caps (Torque Fasteners)
Place the main caps on the block in their designated registers and with all their arrows facing the front of the engine, and then make sure they fit down into their registers. If you tighten the caps before they are seated in their registers, you will damage the block, the cap, or both. Install the bolts with some ARP moly assembly lubricant on the threads. Tighten the mains to a torque of 90 ft-lbs by alternating in 10 ft-lb increments for the nuts, and 45 ft-lbs for the outer Allen bolts. The nuts require a 3/4-inch socket and the Allen bolts require a 5/16-inch bit socket. If you’re using stock hardware with 30W oil, continue to torque the 2-bolt mains to 95 ft-lbs and the 4-bolt mains to 110 ft-lbs. If you are using studs or lubricants that change the bolt torque, refer to the information that accompanies the hardware.
Step 16: Measure Crankshaft(Precision Measurement)
Check the diameter of the main and rod journals with a micrometer. The crankshaft main journals should match each other and the rod journals should match each other. If they are different, contact your machine shop and have them fix the problem. You are going to need to subtract the crank journals from the specs you gathered in steps 10 and 11. That gives you the amount of clearance between the crank and bearings in the mains and rods.
Step 17: Dial Bore Main Bearings(Precision Measurement)
Use your micrometer to transfer measurement of the crankshaft main journals to the dial bore gauge so you know what your clearance is when you read the mains. Use your dial bore gauge to read the inside diameter of each of the main bearings. Write down all your measurements. The four front main bearing clearances should all be within .0004 inch of each other. The rear main usually has about .0005-inch-larger clearance than the other mains. If the main bearing are not in this range, you must remove the main caps and bearings, clean them and start back at step 14. If that didn’t fix the problem, you then need to contact your machine shop and have them fix the crankshaft bore.
Step 18: Plastigage Main Bearings(Precision Measurement)
For this step, you don’t want to put any lubricant on the bearings because the lubricant can take up space in the bearing surface and give an improper clearance reading. With the main bearings installed in the block, carefully set the crank into place. Cut a strip of Plastigage the width of the bearing and lay it across each journal as seen here. You can put a tiny smear of assembly lube in the journal to keep the Plastigage from moving during this process. Place the main caps in their designated places on the block with the bearings installed. Do not turn the crankshaft while checking the clearances with Plastigage because it destroys the plastic and you’ll have to start over again.
Put ARP moly assembly lubricant or a light coat of oil on the hardware (including the surface between any washers and the hardware) so you can achieve proper torque. If you’re installing nuts and they are stamped, make sure the stamping faces away from the surface of the washer. Start tightening all the main cap hardware before fully seating the main caps or torquing anything. If the main cap registers in the block are tight, you may need to tap them with a soft-faced hammer to get them to seat. Make sure they are fully seated before starting to torque them into place. If you are installing 4-bolt main caps, torque all the hardware closest to the crankshaft and then go back and torque the outer main bolts last. Torque the main caps to their proper spec in the proper sequence on page 152. Remove the main caps and check the Plastigage width against the gauge markings on the Plastigage wrapper. Their readings should all be really close to each other. If there is a large gap in the readings from main caps number-1 through 4, clean the Plastigage out completely and repeat the steps; start by removing the bearings, cleaning them, and re-installing them. According to Clevite Oil, clearance on mains number-1through 4 should be from .0007 to .0032 inch, and the rear mains should be from .0012 to .0038 inch. This can vary by bearing type and application, so consult your machinist and paperwork with the bearing set.
Step 19: Bearings for Every Application (Professional Mechanic Tip)
Clevite makes bearings for every application. The main set on the left are bearings you would put in general engine building applications. They have a “P” after the part number (MS-829P). These bearings look really pretty when you pull them out of the box, unlike the “washed” look you get on the “H” bearings. The center set is bearings for performance applications and are denoted with the “H” after the part number (MS-829H). If the clearance is too small and you could use an extra .001-inch clearance, you can get that clearance back by installing a set of “HX” bearings (MS-829HX). The 496 project needed HX rod and main bearings because the clearances were too tight, due to the line-bore done on the block with the 4-bolt main caps installed. These bearings saved the project from having to go back to the machine shop for an additional line-hone or having to grind the crank to remove a small amount of material. This is proof that you really do need to check every part before you install it.
Step 20: Lubricate and Spin Crankshaft (Torque Fasteners)
Once all the readings are within spec, remove the crank and carefully clean all remnants of Plastigage off the journals and bearings. Be sure not to damage the coating layers on the bearing shells or the machined surfaces on the rotating parts when removing the Plastigage. Make sure the crank and all main bearings are clean of debris. Lubricate the bearing surfaces in the block as well as the ones in the bearing caps. Do not install the rear main seal. Carefully place the crank into the block on the bearings. Install and tighten the main caps by using only your fingers. Take a soft hammer and lightly tap the rear of the crank forward to seat the thrust flange up against the thrust bearing surfaces on the rear main bearing. Torque the main caps to 20 ft-lbs using the sequence in step 22, then torque in 20 ft-lbs increments until full torque is reached. Tighten the rest of the main caps and torque them to spec. Now the crank should spin with an easy twist with your thumb and index finger on the snout of the crank. If you’ve done the previous checks and it doesn’t turn freely, your mains need an align bore.
Step 21: Check Crankshaft End Play(Precision Measurement)
Use your dial indicator or feeler gauges to check backward and forward movement of the crankshaft in the block. Dial Indicator: Place the dial indicator inline with the crank with the tip on the front of the snout. Use a screwdriver to carefully pry the crank forward and backward while reading the movement on the gauge. Feeler gauge: Gently pry the crank backward and hold it there. Carefully use your feeler gauges between the thrust flange and the bearing. Start with a .003-inch feeler gauge and move up from there in .001-inch increments until the gauge won’t slide in without force. Don’t force the gauge; you’ll damage the bearing. Clearance should be between .005 inch and .007 inch. If it’s not, contact your machine shop for guidance.
Step 22: Rod Installation Information
Connecting rods have a specific order in which they go onto the crankshaft. On the crankshaft end of the rods, there is a chamfered side and a flat side. The chamfered side is clearanced for the fillet on the crankshaft’s rod journal. The flat side of the connecting rod faces the flat side of the other connecting rod when they are installed on the crankshaft. The pistonwrist- pin end of the rod is considered the reciprocating end and the rotating end is the bearing end, which clamps onto the crankshaft. The chamfer on the stock rod (right) is not as large as the one on the aftermarket rod.
Step 23:Piston and Rod Orientation Rules
Pistons and rods are assembled in a specific way. Unless you’re running low-compression flat tops, your pistons have a valve relief in the two o’clock position on the face for the intake valve. Looking at the piston face, the rods are installed on all eight pistons with the chamfer on the left side. This put the chamfer for the oddnumbered cylinders (1, 3, 5, and 7) facing the front of the engine and the chamfers for the even-numbered cylinders (2, 4, 6, and 8) facing toward the flywheel.
Step 24: Match Rods and Pistons
The connecting rods and pistons use pressed-in wrist pins, which should have been assembled at the machine shop. The numbers on the connecting rods should determine which cylinder the piston goes in. If the pistons are numbered, make sure they match the number on the rods. Mark the top of the piston with a felt-tip marker so that at a glance you know if they are in the correct bore.
Step 25: 25 Install Pistons on Rods
If you are using aftermarket connecting rods with floating wrist pins, check the wrist pin and the wrist pin bore in the rod. These Eagle rod pin bores had .0005-inch clearance, which is unacceptable. These connecting rods need to be taken to the machine shop to have the bores honed out to .0012 inch. Eagle leaves them tight so the builder can machine to desired clearance. If your rotating assembly uses pressed-in wrist pins, apply assembly lube to the wrist pin bores in the pistons and move on to the next step. If you have floating pins, install the clip or ring in one side of each piston, the snap ring with snap ring pliers, or the spiral lock ring worked into the bore, one loop at a time with a small screwdriver or a blunt-tipped probe. Most Spiral lock ring applications use two locks per side of the piston, such as these SRP pistons; so if you’re installing them, put two in one side of the piston. Oil the wrist pins with 30W oil, then lubricate the wrist pin bores and the connecting rod wrist pin bores with Royal Purple Max Tuff assembly lube. Use the previous steps of piston and rod orientation guidelines to position the rod with your pistons. Slide the pin through the piston and connecting rod end. Install the pin-locking clip on the other side of the pin. Use a feeler gauge to ensure the pin end play between the clip and wrist pin is between .001 inch and .008 inch. Locks can work their way out of the piston while the engine is running if the gap is larger or smaller.
Step 26: Measure Pistons
Grab the piston assembly for cylinder number-1. Use your outside micrometer to check the piston skirt according to the position specified by the piston manufacturer. Use your bore gauge to measure the minimum bore diameter in the corresponding cylinder. Subtract the piston measurement from the cylinder bore, and you have your piston-to-cylinder-wall clearance, also known as skirt clearance. Write down your clearance. Perform this process on all eight pistons and their designated cylinder. Piston manufacturing irregularities can and do occur, so check each piston twice. To check skirt clearance with a feeler gauge, slide the piston into its designated cylinder upside down with a feeler gauge between the skirt and the cylinder wall. Start with a .001-inch gauge and move up in size until the piston gets snug in the bore, then subtract .001 inch from that gauge thickness and you have your skirt clearance.
Step 27: Hypereutectic Ring Gap Requirement(Precision Measurement)
Even if you find ring gap information with your piston rings, you also need to check with your piston manufacturer. According to Keith Black Pistons, hypereutectic pistons require a larger gap on the top compression ring because of their design. They make more power by reflecting heat energy into the combustion process, which puts extra heat in the top of the piston and top piston ring. An extra gap in the top ring is required to keep it from expanding too far and breaking the ring and/or the piston. Consult your piston manufacturer to confirm specific gap changes for your application. According to the formula on www.kbsilvolite.Com: bore x .0065 = top ring gap. These KB hypereutectic pistons for this .030-inch over 402 are .027- inch top ring gap. If your application is not a .030-inch over 402, your gap will be different.
Step 28: Insert Ring in Cylinder
If your machine shop gapped your rings, they should be labeled by cylinder. If you have pre-gapped rings you should perform this step to ensure your rings are correct. Make sure each ring has been deburred, and the ends are free of chips. Slide one compression ring at a time into its designated cylinder and make sure the ring is at equal depth all the way around the cylinder. In order to get a correct ring gap, the ring must be square in the bore, which means it must be pressed evenly down into the bore. If you don’t have a ring squaring tool, try using your caliper to set depth. Use a feeler gauge to confirm the gaps are correct and that the ends of the ring are parallel. Don’t forget that the “top” and “second” compression rings have different gaps. If your pre-gapped rings are not correct, confirm your bore size and have the parts store get you the proper set.
Step 29: Measure Ring Gaps(Precision Measurement)
If you are gapping your own rings, designate a “top” and “second” compression ring for each cylinder. Keep them in the order you fit them to each bore. Keep them separated with a paper towel while not working with them. Because you probably don’t have an expensive power ring filer, you need a manual ring filer, a ring squaring tool (it speeds up the process compared to using your caliper), a fine metal file, and a set of feeler gauges. In order to get a correct ring gap, the ring must be square in the bore, which means it must be pressed evenly down into the bore. Because .001 inch can make the difference in how an engine runs, use a ring squaring tool, such as this Goodson unit. Put a compression ring in the cylinder. Once the ring is square in the cylinder, you can get your feeler gauge and check the gap. If your machine shop has not suggested a ring gap, use the chart on page 95.
Step 30: File Rings (Professional Mechanic Tip, Important!)
Pull the ring out of the cylinder and file it down until it has the correct gap. Be careful not to file off too much material. Continually re-insert the ring in the cylinder but make sure there aren’t any burrs on the ring that can scratch the cylinder wall. If there is a burr, lightly touch the corner with a file to remove it. Use the squaring tool and check the gap every time. If you file too much, you can usually purchase single rings. When you’re done with one ring, confirm the gap is parallel, that there are no chips or burrs in the gap, and move on to the next ring. When the compression rings are done, put the oil rings in the bores one at a time and check to make sure they have gaps between .015 and .060 inch. The oil rings are controlling oil, not compression, so they are more forgiving. Pack up the rings in labeled sets and put them aside for later assembly.
Step 31: Measure Rods(Precision Measurement)
While you have the rods torqued, use your caliper to measure the width of rods number- 1 and 2 together and write the measurement for a later step of measuring side clearances. Do the same for rod pairs numbered-3 and 4, 5 and 6, 7 and 8. Put the rods back in the soft jaws and remove the rod caps.
Step 32: Plastigage Rod Bearings(Precision Measurement)
Rod bearings are somewhat trickier to check clearances on with Plastigage than is the crank. The rod and crank want to move while trying to torque the rod cap. Any movement of the rod or crank distorts the Plastigage and gives an incorrect reading. Start at the front of the block and work your way to the rear, installing only two rods at a time. Move the crank so the front rod journal is sticking up as far as it can out of the block. Install and check clearances for only two rods at a time. Install piston and rod assemblies for cylinders number-1 and 2 with the chamfer of the rods facing the fillets on the crank and the two flat sides of the rods are facing each other. Put a strip of Plastigage on the connecting rod bearing surface. Carefully slide both rods and pistons into place on the journal, making sure that you don’t hit the crank or block with the rod bolts. Slide the connecting rod caps into place on their designated rod and install the nuts by hand, but don’t tighten them yet.
Step 33: Improper Rod Torque
If you torque the rod from side to side, it will twist the connecting rod on the journal and also force the crankshaft to turn in the block. Any movement destroys your Plastigage and you will have to start over. This method produces a false Plastigage reading for your connecting rods and possibly damages your new bearings.
Step 34: Proper Rod Torque (Torque Fasteners, Use Special Tool)
Stand directly in front of the engine, and put pressure on the torque wrench toward the front of the engine to torque the cylinder number 1 connecting rod. This puts all the pressure of the rod against the crankshaft, while it limits the rod from twisting and keeps the Plastigage from giving a false reading. Tighten each nut evenly back and forth a couple of times before you reach full torque. With aftermarket rods using alignment sleeves around the bolts to locate the rod cap, pay special attention to the parting line of the rod caps, to ensure they are even as you tighten them, because if they’re slightly crooked, you can damage the rod. The Eagle rods have special caps crew-style rod bolts that required a 7/16- inch 13-point socket on the 1/2-inch-drive torque wrench.
Step 35: Proper Rod Torque CONTINUED (Torque Fasteners, Use Special Tool)
Stand behind the engine and torque the rod for cylinder number-2 by putting all the force on the torque wrench toward the back of the block. This pulls the rod up against the crankshaft, keeps the rod from twisting, and keeps the crankshaft from wanting to turn.
Step 36: Check Rod Side Clearance
This is a feeler gauge method for measuring the rod bearing side clearance. A more precise way to check, with precision measuring tools, should be done in following steps to confirm what you find here. Use your feeler gauge between the two connecting rods without rotating the crank. Take note of the gauge size needed to take up the gap between the rods without having to force it. The gap should be .015 to .025 inch per pair of rods (unless otherwise specified by the manufacturer), making the total gap .020 to .028 inch for the two rods. These Eagle rods came in at .024 inch. When you get all the rods installed, check the side clearance on every journal.
Step 37: Remove Rod Bolts
To remove the rod bolts, you must use the opposite procedure from the way these were installed, while still pushing the rods against the crank. To remove the nuts for cylinder number-2, stand in front of the engine and put all the pressure toward the back of the engine. To remove the nuts for cylinder number-1 stand behind the engine and put all the pressure on the wrench toward the front of the engine. Use a 12-point 7/16-inch socket and a flex-handle ratchet.
Step 38:Remove Rod Cap
Because Plastigage is a pliable piece of plastic, you have to be extremely careful not to rotate the crankshaft during this process. If you have rod cap bolts (on performance rods), loosen the rod bolts a few threads and use a soft-faced hammer to gently tap the rod bolts. Tap each side evenly until the rod and rod cap separate. If you have stock-type rod bolts and nuts, loosen the nuts a few turns and use a pair of channel-lock pliers to gently pry the cap off the rod bolts without disturbing the parting line (faces of the cap and rod that touch each other when installed). Remove the nuts (or bolts in the case of aftermarket rods) while being careful not to allow the piston and rod to fall on the floor. If you have bolts sticking out of the connecting rod (as with stock), you should install your rod bolt protection now. Carefully slide the rod out of the bore without damaging the crank or cylinder wall. Follow the same method and remove the other rod on the journal without turning the crankshaft.
Step 39: Check Plastigage for Rods(Precision Measurement)
The Plastigage gets wider as it is crushed. The tighter the tolerance on your bearings, the wider the Plastigage ends up when you remove the bearing cap. Compare the width with the chart on the Plastigage package. Clevite suggests oil clearance to be .009 to .0034 inch. This will change with some bearing sets and applications, so consult your machinist and paperwork with your bearings. If your clearance is not within spec, consult your machine shop to see if you can remedy the problem by installing some undersized or oversized bearings. The 496 Eagle rods and mains required “X” Clevite bearings to give extra clearance.
Step 40: Measure Crankshaft Rod Journal Clearance
Using your caliper, measure the width of each of the crank journals. Measure with the caliper tangs positioned flat against the journal thrust faces. Refer back to the measurements you took in step 36. Subtract the rod pair widths from the journal widths and you have your rod bearing side clearance. Refer to the clearance chart on page 99. If the specs are not in the proper range, check everything again and contact your machine shop.
Step 41: Install First Pair of Pistons
Now we’re going to be checking for TDC. We’re going to be working with cylinders number-1and 2. To get to this step, the crank has been installed and lubed. The pistons have been installed on the rods and the bearings are installed in them. First check the crank to make sure you can slowly rotate it a couple of revolutions. Grab number-1 piston and pivot the connecting rod back and forth (without knocking the skirt on the rod beam) to make sure there isn’t any bind, then check number-2. Lightly oil the piston skirts and the cylinder walls. Lubricate the rod bearings and the front rod journal on the crank. Install rods and pistons (without rings) number-1 and 2 in their correct bores and torque them to spec. Slowly rotate the crankshaft by hand. If it doesn’t spin easily or binds, don’t force it. Something has gone wrong with the installation of the rods or the rods may be hanging up on the engine block. Check for possible interference problems with the rods or, if necessary, check the rods and bearings for damage.
Step 42: Install Camshaft (Use Special Tool)
Put a thin coat of engine oil on the cam bearings and on the cam journals. You can use a long bolt, the cam sprocket, or a camshaft handle like this Goodson tool. Carefully insert the cam straight into the the block. Turn the cam gently as you install it to ease it into the block. Be sure to support it, so the cam lobes don’t fall and knock the bearings, especially when the journals slide past the bearings. If the cam doesn’t slide into the bearings easily or turn freely, there could be a problem with the installation of the bearings or the bearings could have been damaged upon installation. If this happens, carefully remove the cam and check it for straightness. Inspect the bearings for shiny high spots. If there are a few small high spots, sometimes you can remove them by carefully scraping them with a bearing knife. If the cam isn’t bent and removing high spots doesn’t work, the machine shop must check and repair the cam bore.
Step 43: Install Keys and Sprocket
Once the cam fits correctly, remove it, put more oil on the journals and put more assembly lubricant on the lobes, and then carefully put it back in the block. If you’re installing a Milodon gear drive, follow the steps for doing so in the “Milodon Gear Drive Install” sidebar on page 100; if not, continue this step. The keys should already be installed in the crank but if not, go ahead and install them by tapping them gently with a non-marring hammer. Once installed, put a small amount of anti-seize on the snout of the crank and slide the small timing sprocket onto the snout, positioned so the flat side with the timing marks is facing away from the block. Some sprockets have more than one keyway and different marks, such as triangles, round dots, and other shapes. With the crank key installed, align the keyway with the zero (“0”) mark and drive the sprocket onto the snout with a crank socket or a brass drift by tapping it lightly with a hammer around the flat surface of the sprocket.
Step 44: Install Timing Set
Rotate the camshaft so the dowel pin is in the three o’clock position and the crankshaft key is also in the three o’clock position. Put the timing chain on the cam sprocket and let the chain hang down. Hold the cam sprocket with the timing mark in the six o’clock position. Loop the chain under the crank sprocket, and slide the cam sprocket onto the cam dowel pin. The timing mark positioning is critical. The timing marks on the cam and crank sprockets should be lined up as shown. If they don’t, reposition the chain and/or sprockets until they do, then install the three bolts snugly.
Step 45: Install Cam Degree Kit and Final TDC (Important!)
If the crank turns freely, go ahead and rotate the crank until the number-1 piston is as close to TDC as possible. Install your cam degree wheel, such as this one that came in a complete kit from Crane Cams. Install your pointer (or bent coat hanger with a pointed end) on the zero mark of the wheel. There are many methods to find exact TDC; I prefer not binding the piston with a stop by using a dial bore gauge on a magnetic base on the deck surface. Set the dial at zero. Rotate the crank counterclockwise to where the gauge reads .070 inch down, then rotate the crank clockwise until the gauge reads .050 inch down, and then record the reading on the degree wheel. Then continue clockwise past TDC to .050 inch down on the dial gauge and record the reading. Adjust the pointer or degree wheel until the degree on the wheel matches at .050 inch down before and after TDC and you have found TDC.
Step 46: Piston-to-Deck Clearance(Precision Measurement)
To start with, the piston dome needs to match the combustion chamber configuration for your heads. Next, there should be a minimum of .060 inch between the piston and chamber. If the piston is .030 inch below the deck, you need to run a head gasket that compresses to .030 inch below the deck. If the piston is .040 inch below the deck, your head gasket needs to compress to a minimum of .020 inch. If your piston is less than .050 inch below the deck surface, you need to be concerned with the piston hitting the head. Piston-to-head clearance is calculated by adding the piston-to-deck clearance and the thickness of your compressed head gasket. To determine the piston-to-deck clearance, bring number-1 piston to TDC. Mount your dial indicator to a deck stand like this one from Goodson and stick it to the deck as shown. Without moving the crankshaft, gently rock the piston by pushing down on the bottom of the piston and take your reading, then push down on the top of the piston near the gauge to rock the piston the other direction and take your reading. Take the average of the two readings and add the result (or subtract if your piston is higher than the deck surface) to the compressed head gasket thickness and you have your piston-to-head clearance. This measurement can be found by using a straight edge and some feeler gauges.
Step 47: Piston-to-Head Clearance(Precision Measurement)
Many big-block pistons have a domed face and need to be checked for clearance to the head. Hopefully you read my warnings in Chapter 5 and didn’t purchase open-chamber pop-up pistons for closedchamber heads, or you will have interference problems in this step. Using a few head bolts, lightly bolt the left cylinder head on the block without the head gasket. Bring the number-1 piston to TDC. If the piston binds, don’t force it (install shims the thickness of your compressed head gasket in place of the head gasket). Remove the rod cap from number-1 rod. Make sure the rod bearing is still contacting the crank, place the dial indicator on the top of the rod bolt, and zero the gauge. Slowly push the rod into the cylinder toward the head. When the piston contacts the head, you have the piston dome-to-head clearance on the gauge. Add the reading to the head gasket thickness and you have your dome-tohead clearance If it’s less than .050 inch, contact the machine shop and find out if a thicker head gasket will fix the problem. When you’re done, re-install the rod cap and remove the cylinder head and dial indicator.
Step 48: Hydraulic Lifter How-To
If you are installing a hydraulic cam, modify a few of the lifters so you can use them in the following steps. Hydraulic lifters have a spring inside that compresses when you need the plunger inside the lifter to stay stationary, while you check clearances to the thousandth of an inch. Professional engine builders swap in a couple of solid lifters for these tasks, but if you don’t have access to some that are the same “cup” height as the hydraulic lifters, you can take apart a pair of old lifters that are still in great shape (no scuff or scars on the face of the lifter-to-cam surface) and modify them. Place the lifter on a non-marring but solid surface, push the piston cup down with a pushrod, and remove the snap ring. Sometimes suction in the lifter won’t release the piston, so you can carefully push the end of a paper clip into the small hole in the bottom of the internal piston, so the internal valve opens. This releases the suction in the lifter and causes the pistons to slide out of the lift bore. Remove the spring under the piston and add spacers or washers so the clip just fits back in the lifter.
Step 49: Find Camshaft Base Circle (Important!)
Apply engine oil to the outside and face of two lifters and slide them into the exhaust and intake lifter bores for number-1 cylinder. If the lifter hangs up in the bore, don’t force it; pull it out and resolve the problem. Using your magnetic stand, place the dial indicator on the top edge of the intake lifter. Make sure it is parallel to the lifter. Rotate the crankshaft until the intake lifter is at its lowest position in its bore (the base circle of the camshaft). Gently push the lifter down to confirm it is touching the camshaft lobe.
Step 50:Confirm Cam Specs(Precision Measurement)
Pull out your cam card (the spec sheet that comes with your camshaft) and check the valve timing specs. Most cam timing specs are measured at .050 inch. Slowly rotate the crank clockwise, which is the way the crank turns while it’s running, until the intake lifter raises the correct amount (.050 inch, in this case). Write down the degree indicated on the wheel and continue clockwise until the lifter reaches the same lift (.050 inch, in this case) as it goes back down on the other side of the cam lobe. You must always go through this cycle in a clockwise motion; so if you miss the reading on the back side of the cam, you can go back but you have to go past the reading, perhaps to .060 inch. Then go clockwise again to get the reading again. The opening and closing readings should match the ones on the cam card. Perform the same procedure on the exhaust lifter. Our cam card showed opening at 0 degrees, which matched our reading.
Step 51:Find Optimal Timing (Professional Mechanic Tip)
Many companies offer timing chain sets for setting them with advanced timing, at zero, or with retarded timing. Some timing sets allow you to interchange a bushing on the camshaft dowel pin for fine tuning and some sets, such as this Hex-A-Just chain offered by Edelbrock, allow you to adjust the cam timing with a turn of the adjustment screw before tightening the cam gear bolts. These adjustable sets allow the builder to correct timing if your cam doesn’t match the specs of your cam card. The adjustments also allow you to alter your timing for increased power at different RPM ranges. Without a good grasp on the effects of deviating from a zero setting, and without space to devote a few chapters to camshafts, you should set the cam at zero and leave it. Engine builder Paul Caselas says, “Hopefully you purchased the cam you wanted and you can install it without altering the timing.” When you’ve set your timing, record the settings and keyways by marking the gears and writing your changes on your worksheet for reassembly in the next chapter. Take the lifters out of the block and put them away for now.
Step 52:Check Stroker Clearance
Install the other six pistons and rods using the instructions in step 41. Stock engine rebuilds won’t have rotating assembly clearance issues but when you are changing the stroke and installing performance pistons, you need to check for internal interference. Carefully turn the crank and make sure to stop at any sign of bind. If there is any bind or drag on the crank, find the offending culprit and fix it. It could be rod bolts hitting the block near the oil pan rail, the rods hitting the bottom of the cylinder walls, or the crank counterweight hitting the bottom of the piston or the inside of the block. If you have to remove any material from the block or modify any parts for clearance, refer to Engine Blueprinting by Rick Voegelin. If the rotating assembly is not contacting the areas mentioned, make sure you installed the rods correctly.
Step 53:Install Windage Tray and Fit Oil Pan
Now that you know the block and rotating assembly are free of interference, it’s time to confirm that your windage tray (if you have one) and pan fit. Install the windage tray and adjust its height with the double nuts on the ends of the main studs and rotate the crank to make sure there is at least .10- inch clearance between the rotating assembly and the tray and/or screen. Once that’s adjusted, thread a couple of bolts in the oil pan without the oil pan gasket. If the pan doesn’t fit over the tray, you may need to adjust the tray height or trim the excess threads off the mounting studs and possibly trim the edges of the tray. Be careful when cutting the studs; don’t damage the threads. Carefully chamfer the ends with a fine file to ensure the threads are in good shape. You can lay a shop towel over the tray, place the oil pan over it, and lift it off. The towel has marks showing where the interference may exist. Once the pan clears the tray, put it back on and rotate the crank; if it binds, the pan moves, or the crank doesn’t easily turn, identify where it’s hitting and address the issue. If you are building a stroker, you may need an oil pan with stroker clearance at the rail, such as this Milodon oil pan. If the clearance is very tight, you can place a washer between the block and the pan to simulate an installed oil pan gasket. Some dimpling of the pan may be necessary on some pans; but if your pan needs a lot of work, you may consider buying another that may fit better. When you are done checking clearances, pull the pan off and write notes on your worksheet as to where you had set your windage tray, but leave the tray in place for now.
Step 54:Check Crankshaft Index (Important!)
This step verifies that the rod journals are correctly indexed on the crankshaft. Start by using the instructions in step 45 to re-check the accuracy of the pointer on the degree wheel and TDC of number-1 piston. Perform the same steps on pistons number-3, 5 and 7. TDC for the following pistons should index on their perspective degree marks on the degree wheel: number-3 at 90 degrees ABDC, number-5 at 90 degrees ATDC, and number-7 at 180 degrees BDC. Because pistons number-2, 4, 6, and 8 share journals with pistons number-1, 3, 5 and 7, you don’t need to check their TDC. However, you should check the piston height on all eight cylinders with the dial caliper to make sure they all match. It’s acceptable to have up to .005-inch difference between all eight pistons in stock and light-duty applications. High-performance applications have closer tolerances and require zero difference.
Step 55:CC Chamber
You can always use the pistons you ordered as a guideline for your engine’s compression ratio, but the head’s combustion chamber cc can significantly change your compression ratio.
Step 56:Keep Valves in Place
Ready the heads for the next steps to check clearances. Because low-tension “checking springs” are typically sold in pairs (except the Crane degree kit that comes with eight springs), you must install them on cylinder number-1 and put O-rings on the other valves to keep them in the seated position. If they drop into the cylinder during this process, you’ll have to remove the head to fish the valve out of the cylinder. Using checking springs keeps you from needing to remove and re-install the head each time you want to run the following checks for each cylinder. When moving the checking spring to the next set of valves, position the piston at TDC for that cylinder to ensure the valve doesn’t drop while in the process. The only other way to get around this is to get enough checking springs for each valve.
Step 57:Check Rocker Geometry(Precision Measurement)
Not all head castings are perfect, so the rocker arm stud and valve location geometry can be off enough to cause improper rocker-to-valve contact, which can cause rocker failure and/or the rocker to wear on the valve retainer. It’s suggested to check all 16 rockers, but at least check intake and exhaust rockers’ cylinders number-1 and 2 (one on each head). Install both heads with a few bolts hand tightened (without head gaskets) with low-pressure valve checking springs installed. If you have mechanical lifters, you’re set, but if you have hydraulic lifters, you have to perform step 48 on page 106 to remove the hydraulic function, or temporarily use mechanical lifters with the same cup height as your hydraulic lifters for the following steps: Check all four lifter bores on cylinders number-1 and 2 for burrs and debris; apply Royal Purple Max Tuff assembly lubricant to the face and sides of the lifters and gently re-install them for cylinders-1 and 2 if they hang up, don’t force them; install the pushrods and rocker arms for cylinders number-1 and 2, using non-locking nuts; and, rotate the crankshaft and if there is any bind, stop moving the crank!
Because your engine passed bind checkups to this step, there are two new possible interferences: rocker arm bind on the stud, or valve-to-piston interference. If you are using stock-style stamped rocker arms, make sure there is at least .040- inch clearance between the rocker slot and the rocker stud at maximum lift (refer to arrow). If the rocker is too close or bound on the stud, you need long-slot rockers as discussed in Chapter 5. If the rocker clearance is okay, remove the rocker arms and see if that fixes the problem. If the valves are hitting the pistons you should contact your machine shop or refer to Engine Blueprinting by Rick Voegelin before modifying anything.
With hydraulic lifters for cylinder number-1 on the heel (the section of the cam without lift), the rockers should barely touch the valve tips but not compress the valve. The rocker should be on the inside tip of the valve. Turn the crankshaft and the rocker should move from the inside of the valve tip to the middle and then to the outside of the valve tip. The rocker should be in the center of the tip when the cam is half way through its valve lift (according to the cam card). At no time should the rocker tip be off the edge of the valve tip.
Step 58:Check Pushrod Length(Precision Measurement)
The last part to purchase for your engine should be the pushrods, after you get through this step. Obtain a set of adjustable pushrods like these from Crane Cams to find the optimum length. Put the cam on the base circle, and adjust the pushrod out (including your lash setting at the valve), or pre-load on the lifter (generally .030 inch to .060 inch). Rotate the camshaft and watch the rocker tip; it should never roll off the tip of the valve. It should always favor the center of the valve tip through its travel. For guide and seal life, you are looking for the shortest travel on the valve tip.
Step 59:Rocker Position(Critical Inspection)
Make a quick visual inspection to be sure the rockers are square on the tips of the valves. They should not be hanging way off the side of the tip because this could cause extra side loading on the valve, cause extreme premature wear, or, at higher RPM, the rocker tip could move off the tip of the valve and hit the retainer.
Step 60:Seal Clearance and Rocker Ratio(Precision Measurement)
At maximum lift, the retainer should have at least .070 inch of clearance to the top of the valve seal or valve guide. The rockers should not contact the outside edge (closest to the rocker stud) of the retainers during full articulation. Mount the dial indicator so the point is pushing on the valve retainer, and measure the actual lift at the valve to confirm you have the right rocker arm ratio for your application. Aftermarket rockers come in ratios ranging from 1.6:1 to 1.9:1, so checking ratios is important so you can change the performance of an engine as well as piston-tovalve clearance.
Step 61:Check Piston-to-Valve Clearance
At this point, the valves should clear the pistons and it’s time to confirm how much piston-to-valve clearance (PTVC) you actually have. Rotate the crank clockwise until the number-1 piston is at TDC while both valves are open (valve overlap). Mount the dial indicator on the head, so it’s riding on the intake valve retainer and parallel to the valve. Push the tip of the rocker arm down until the retainer hits the valve seal or valve guide, or the valve hits the piston. Take notes on the PTVC on your worksheet. Release the pressure and confirm the pushrod tip falls back into the cup of the lifter plunger. Rotate the crank 2 degrees and check the PTVC, and take notes. Continue this procedure until you get to 12 degrees ATDC. In that range, you should have read your minimum PTVC. If you move the crank past the degree mark at any point, you need to back up 10 degrees and approach the mark in a clockwise direction. Repeat this procedure for the exhaust valve and, then, if you don’t perform this check on all the other cylinders, do at least cylinder number-2, so you know both sides of the engine have enough clearance. Minimum safe PTVC on the intake is .100 inch and .080 inch on the exhaust. Check clearances on all cylinders if any clearances are close to minimum specs because some may be closer than others. Remove the rockers, pushrods, and lifters and put them away for now.
Step 62:Check Distributor and Oil Pump Fitment (Critical Inspection, Precision Measurement)
Without intake gaskets on the heads, install the intake manifold with the four corner bolts hand tightened. You are going to install your distributor without an ignition cap or gasket. Lightly oil the distributor gear and carefully slide it down into the hole in the back of the intake manifold. With a slight turn of the distributor shaft or rotor, it should mesh with the gear on the camshaft and drop against the intake manifold. Tighten the distributor hold-down bracket. Carefully rotate the engine upside down. Hopefully you took my advice from the oil pumps section on page 57 and replaced your stock oil pump drive shaft. Slide the shaft down into its hole in the rear main cap and turn it to make sure its two forks completely drop into the tab in the center of the distributor gear. Hand tighten the oil pump on the rear main cap. The oil pump should sit all the way down on the main cap and the shaft should move up and down a little bit. Mark the oil pump shaft with a fine-tipped marker, with the driveshaft down, and then use your finger to lift the driveshaft and mark the oil pump shaft again. When you remove the pump, you can measure the distance between the two marks for your clearance. There should be .010 inch to .040 inch of play in the shaft. If the shaft is too long, the oil pump won’t even tighten down all the way. If this happens, refer to “Setting Distributor Height” on page 139.
Step 63:Install Oil Pump Pickup (Torque Fasteners)
Pull the oil pump off and remove the oil pump drive shaft, then re-install the oil pump to full torque. If you are building a big stroker, slowly rotate the crankshaft one revolution to confirm the crank clears the pump. Lay a couple of paper towels over the rotating assembly to catch shavings of metal that usually come off the pickup tube during installation. Get your oil pump pickup, and a pickup installation tool (like this one from Goodson). Stick the pickup in a plastic bag and into the freezer for a couple of hours next to the taquitos, to help shrink the pickup tube. Lubricate the end of the pickup and the pickup opening on the pump. Drive the pickup onto the pump as level as possible to start. If you are installing an aftermarket oil pan, install the pickup designated by the manufacturer to go with the pan. Some aftermarket pickups have a tab that locates it to the pump by using one of the pump cover bolts, like this Milodon pickup. If this is the case, go ahead and remove the correct bolt. This pickup had a sturdy square tube joint so we were able to use a brass drift to drive it onto the pump. Some pickups use the same manner of installation as a stock pickup; torque the cover bolt to 10 ft-lbs.
Step 64:Tack Weld Oil Pump Pickup
Lay the oil pan on the engine without the pan gasket to confirm the pan clears the pickup. If you have a pickup without a mounting strap, turn the pump slightly upward and lay the pan over it until the pickup barely holds the pan off the block. Push the pan down, which pivots the pickup down on the pump. Unlike factory pickups, Milodon takes the time to weld a clearance strap on its pickups. This ensures adequate clearance between the pickup and oil pan during installation and just in case the oil pan were to get dented upward while driving on the street. Pull the pan off and lay a 1/4-inch-thick piece of wood on the screen part of the pickup, lay the pan over the engine again, and push the pan down to where the pan rails touch the block. This makes sure you have 1/4-inch clearance between the pickup and the pan before installing the pan gasket. According to Ken Sink at Milodon, the optimal clearance between the pan and the pickup (with oil pan gasket installed) is between 1/4 inch and 3/8 inch. Anything more and your pump could become a suction vortex at the pickup and air could enter the system in extreme cases, resulting in bearing failure.
Tack Weld Oil Pump Pickup CONTINUED
If you have an oil pickup with a mounting tab, confirm that there is a proper gap between the pan and the pickup and that the pickup doesn’t interfere with bolting the pan to the block. To fit correctly, some aftermarket pans require the same company’s oil pump as well as their pickup. Mark the position of the pickup and for welding it into position. The best practice for welding the pickup to the pump is to take the cover off, pull the gears out, and remove the spring from the body. This ensures that heat does not distort any components and won’t damage the spring by overheating it. I took this pump to Vic DeLeon at Goodies Speed Shop of San Jose, California, and he had a tried-and-true technique of welding the pickup without heat soaking the pump. First, he used a die grinder to give a good welding surface. Then he connected the grounding strap for the welder to the pickup to pull the heat away from the pump, and he wrapped a cold and wet shop towel around the pressure spring area of the housing to reduce heat soaking the spring. A quick tack weld kept the heat from causing problems. The pump was cool enough to handle within seconds. Strapped pickups don’t require welding because the strap keeps the pickup in place, but if movement was necessary you can usually do some tweaking with a soft-faced hammer.
Step 65:Check Intake Manifold Fitment(Precision Measurement)
Remove the heads from the block. Clean any oil off the head gasket mating surfaces on the block and heads, lay your new head gaskets on the block and install eight head bolts (distributed evenly around the head) hand tight (less than 5 ft-lbs of torque). Lay the intake manifold in place without the intake gaskets. Check the angles of the intake manifold against the angles of the heads. If the angles are even 1/2 degree off in one direction or the other, the intake manifold gasket will not seal properly, causing vacuum and coolant leaks under the intake into the engine block or on top of the intake. These problems can be tough to diagnose. Inaccurate or improper machining causes these incompatible angles. Pull the intake manifold off and make sure the intake gasket surfaces are clean. Temporarily lay the two side gaskets (intake-to-head gaskets) on the heads and carefully lower the intake on the block. Use a small Philips screwdriver in the bolt holes to reposition the gasket while barely lifting the intake. Hand thread all the intake bolts two or three threads to confirm the bolt holes all line up. Lightly hand-tighten the bolts at all four corners. Use your feeler gauges to confirm the gap between the ends of the intake manifold and the front and rear block rails is at least .060 inch. Consult your machine shop if this clearance doesn’t meet the requirements.
Step 66:Check Accessory Fitment & Re-Check Changes(Important!)
Any custom bracketry or stock bracketry that may have changed during the rebuild process can be temporarily bolted to the block and heads to ensure a hassle-free assembly in the next chapter. Double-check the threads in the heads to make sure you can easily thread your bolts into them because it would be easier to take a head to the machine shop than the entire engine. Any parts that may get mixed up or clearances you forgot to check should be noted and marked during this step, before heading off to the next chapter when everything is installed for good. At this point, also re-check any clearances that may be changed by any additional machine work that has to be performed. It would be a pain to start over in this chapter, but it’s an even bigger pain to have your engine only last 10 seconds because you took a chance on something. Take everything apart carefully and clean up everything before going to the next step. It makes the engine building process much easier.
Step 67:Install Valve Seals
Now you are completely done with all clearances and checks so you can fully assemble your cylinder heads. Make sure you put all the parts exactly where they were pulled from, especially any shims that were under the valvesprings. Because you won’t be removing the valves again, you can install the valve-stem seals. There are a few different types of valve seals. Umbrella- and press-on-type seals are the most common. Umbrella seals simply slip over the valve stem and valve guide, but don’t actually attach to the top of the guide. Press-on-type seals actually have to be pressed over the valve guide. If you are using press-on-type seals, the machine shop should have made sure that any required machining has already been done. You can carefully drive it onto the guide with a socket that sits on the outer edge of the metal body of the seal and then install the valve. Most valve seals come with a protective sleeve that you slide over the tip of the valve stem before sliding the seal over the tip, where sharp edges can damage the seal.
Written by Tony Huntimer and Posted with Permission of CarTechBooks
This is just one small part of the full book! It is packed full of in-depth “how-to” instruction and images. Perfect for a true DiY’r! [button type=”churchope_button” url=”https://www.cartechbooks.com/how-to-rebuild-the-big-block-chevrolet.html?utm_source=chevy_diy&utm_medium=blog_post&utm_campaign=sa142P” target=”on” button_color_fon=”#EE2125″ ]I WANT THE FULL BOOK[/button]