I covered some of the following items in the last chapter. As an extra precaution, though, they are being mentioned again. In the heat of the moment of wanting to fire your engine, it’s easy to skip over a step or two by accident. The importance of slowing down, reviewing your plan, and making sure everything is done before firing the engine, can’t be stressed enough. Even seasoned veterans occasionally forget some of these steps.
Check to make sure the oil filter is in place, the oil drain plug is tight, and the engine has enough oil. If you’ve skipped the pre-oiling step, it’s easy to forget these and damage your engine or, at minimum, have the huge mess of a few quarts to clean up off the driveway.
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You should have connected the bypass hose between the water pump and the intake manifold, the heater hoses, coolant plugs in the block, heads and intake manifold, and the upper and lower radiator hoses. Once those are all connected, it’s time to add coolant and water to the system. If you care about your engine, don’t fill your radiator with tap water. It’s really easy to grab the garden hose and add water, but fight the urge. Tap water is full of minerals that love to damage your system, and garden hoses are rarely free of bugs and debris. Tap water mineral content is different for every city. If your city tap water is “soft” (low mineral content) you can take your chances with your garden hose. For example, the water in San Jose, California, is so “hard” that my 12-month-old faucet looks like it’s made of sandstone. You can be your own judge and take your chances. The best water to put in your cooling system is distilled water that you can purchase by the gallon at the grocery store.
Step1:Install Fuel Lines
If you’re upgrading the performance of your engine, you need to consider the amount of fuel your system can deliver to the carburetor. A 6-cylinder 1960s muscle car had 5/16-inch-diameter fuel lines. The 3/8-inch fuel lines fed the standard bigblock V-8s, and 5/16-inch lines will starve the big-block, causing piston-damaging lean conditions. Any carbureted application making more than 500 hp should upgrade to 1/2-inch fuel line and 5/8-inch line if more than 750 hp, to be safe. Contact Aeromotive Fuel Systems or Barry Grant for suggested fuel system design and upgrades.
If you are filling a system that you know is in good shape (hoses, heater core, radiator, etc.), you can confidently fill your system with a 50/50 mix of coolant and water. You can simply fill it with water only if your engine is going in a racecar or you have a hunch you may need to drain the fluid to repair the system.
There will be multiple air pockets in the system when you fill the cooling system. They give the false impression that the system is full. Big-blocks trap air in the cylinder head coolant passages. If you have a temp sender in the intake manifold next to the thermostat, you can easily loosen it to release trapped air. Fill the radiator and allow it to transfer into the block multiple times before assuming the system is full. If you are on a steep driveway, be sure the front (radiator) end of vehicle is facing uphill. Don’t forget to tighten the radiator cap before moving to the next step.
Make sure the throttle cable is connected and that there are two throttle return springs. The second is a safety spring. I’ve seen return springs break, causing the engine to rev uncontrollably. Think of the second spring as an insurance policy.
Wires and Hoses
Connect all the wires and hoses to your engine by referencing your photos (or diagrams) and the labels on the wires. If any labels fell off, connect the ones with labels and focus on the leftover connections. Over time, wires and hoses form “memory,” and they usually lay close to where they were connected. Many older cars came with the factoryequipped idiot lights instead of water temp and oil-pressure gauges. Keep better tabs on your new engine and install some more precise gauges. If you’re connecting a mechanical oil pressure gauge, you’re much better off installing copper tubing instead of the nylon tubing they supply. If the nylon burns through on something hot, you’ll start pumping oil out of your engine. Copper tubing is much more reliable.
Don’t forget to make sure you have at least two ground cables connecting the engine to the chassis or body. Without them, you are asking for starting issues.
Accessories and Belts
If you haven’t done so yet, install the last of the leftover accessories. Check the belts for damage and signs of aging. Replace them if necessary. Tighten the belts, but realize new belts will stretch a little and usually require re-adjustment after the engine has been running for a few hours.
An engine won’t work without fuel to ignite. Make sure the fuel lines are in good shape, are connected properly, and are the proper size for your application. If your vehicle wasn’t factory equipped with a big-block, the fuel lines may be too small for your new requirements. Even big-block-equipped vehicles have 3/8-inch fuel lines, which may be too small for your new engine. The 496 engine is going to easily produce more than 550 hp. A 5/8-inch line feeds the Barry Grant 850 cfm carb and a 3/8-inch line returns to the tank. A 5/16-inch feed line is too small for a 375-hp big-block. Check your line size. A new fuel filter is a good idea and can be had for very little investment, depending on what you want. If they have a specific flow direction, there will be an arrow on the housing; so, pay attention.
Don’t overlook the fuel in your fuel tank. If your car hasn’t been running for a few months, and the fuel hasn’t been treated with fuel stabilizer, the fuel has probably turned to shellac and isn’t going to ignite well. It would be ridiculous to try to run your new engine on garbage. Do yourself a favor and siphon the old fuel out of the tank. If that garbage doesn’t ignite, you’re going to spend time trying to figure it out and after a few turns of the starter all the assembly grease will be wiped off your cam lobes. Then, you’re at high risk of flattening your cam on breakin. The engine needs to run right away and run continuously for 15 to 20 minutes for best break-in results. Put at least five gallons of fuel in the tank. The five gallons should safely get you through your break-in period and some test driving. If you add less fuel and run out of gas during break-in, you’re asking for problems.
If you have an electric pump, disconnect the fuel line just before the carburetor and stick it in a fuel can and turn the electric pump on, without starting the car. This will get as much debris out of the line as possible, so it won’t get into your carburetor. If you have a mechanical pump, you’d have to siphon the fuel up to the front of the vehicle.
Does it have a charge? If you have electronic ignition, you’re going to need at least 11 of your 12 volts to start. Any less and you may not get your ignition to fire, unless you’re using a points-type ignition. Is your battery in good condition? In some cases a battery can have a 12-volt charge, but have a bad cell that causes starting gremlins. If you have doubts about the condition of your battery, take it to a shop you trust and have them test it. If you’re building a performance engine, you may consider upgrading to a performance battery like an Optima or PowerMaster.
Connecting the battery is the last task when working on any part having to do with electrical connections. Connect the positive connection to the battery first, then the negative cable.
It’s time to pre-oil your engine if it’s been more than seven days since you assembled your engine or if you skipped the pre-oiling step at the end of the previous chapter. Loosen the distributor and pull it out of the engine. Grab your drill and clean all the dirt and debris off its body and out of the drill chuck because metal and wood shavings love to get up into the drill chuck and fall into your engine. Insert the oil-priming tool into the drill. Insert the primer into the engine and line it up with the intermediate oil shaft. Set the drill to turn clockwise. Prime the engine for 30 seconds. Depending on the power of your drill, you should get decent oil pressure at your oil pressure gauge while using the oil primer. Crane Cams notes that bigblock Chevy engines are notorious for taking a long time to fully prime. They say it can take as much as 20 minutes, while rotating the crankshaft periodically, in order to get oil all the way up to all the lifters.
If you had to pre-oil your engine, you’re going to need to re-time your engine and set the distributor back on TDC. Use the timing information in “Initial Timing” to perform this task properly. Remove the valve cover over number-1 cylinder to confirm the valves are closed while the piston is at TDC. This is not the time to take chances and accidentally reinstall the distributor off by 180 degrees. During every rotation of the engine (trying to get it started) the lifters are pushing the assembly paste off the lobe. That paste is protection against intense friction. Cams and lifters get damaged while people try to get their engines started.
If you have an automatic transmission from which fluid has been drained, you’ll need to add more to keep it from burning up on break-in. Consult your local transmission shop for fluid advice on your specific transmission. The fluid level doesn’t have to be perfect upon break-in but don’t overfill it. Once you’re done breaking in the camshaft and lifters, you can drop the idle and get the transmission fluid level correct.
Manual transmissions should have the fluid topped off properly before firing the engine. Don’t forget to do it before you drive off for your maiden voyage.
With the distributor set in the instructed, correct position, go ahead and slightly rotate the damper to align the zero mark on the harmonic damper with the 12-degree before top dead center (BTDC) mark on the timing tab. Hook up all the ignition wiring, distributor cap, ignition rotor, and spark plug wires. Pull the number- 1 spark plug out of the head (or you can use a spare spark plug) and connect it to the end of the number- 1 spark plug wire. Ground the spark plug to a known ground. Loosen the distributor hold-down fastener enough that you can easily turn the body of the distributor. Without starting the car, turn the ignition on to energize the coil. Be careful not to shock yourself or move the distributor body clockwise and counterclockwise until you see the spark jump the spark plug electrode. As soon as the spark jumps, stop moving the distributor and snug the hold-down fastener down tight enough to hold the distributor in place (so it can’t turn by itself when the engine is running), but not so tight that you can’t rotate it with a little muscle. Now your ignition timing is set at approximately 12-degrees BTDC, which is accurate enough to get your car started for break-in. You can reset the timing with a timing gun later after you get the car started.
Pick Up Your Mess
Your parents tell you that a few times while you are growing up. They were just trying to get you ready for rebuilding your big-block Chevy. Remove all the tools from your engine compartment right before you fire your engine. Tools tend to fall off of fender wells and radiator supports when the engine is running. The last thing you need is a screwdriver rolling into your fan and maiming you or your radiator. Make sure there aren’t any tools or items resting on the headers or exhaust manifolds. Confirm that the cooling fan is not obstructed and is in good working order.
Put your tools on your workbench or a place nearby so you can access them if necessary. There’s a good chance you’ll need access to a standard screwdriver and a couple of wrenches during break-in.
Flat Tappet Cam Break-In Process
The camshaft and lifters need to go through a process of “mating-in” with each other. The lifters rotate while they glide on the face of the cam lobes to complete the “mate-in” process. The camshaft lobes are machined with a slight taper and the lifter’s site slightly off-center, this and initial high RPM induce lifter rotation. If the lifters don’t rotate, they simply grind into the camshaft and quickly turn into thousands of metal shavings in your oil. The damaged lifters also grind the lobes off the cam, and valve lift decreases. Without the ramps on the lobes, the cam is considered “flat.” Having the RPM over 2,500 helps the lifters turn so they can mate-in to the camshaft properly. The first 20 minutes of running is the most important for flat tappet cams, hydraulic or mechanical.
Every camshaft manufacturer has a slightly different RPM and length of time required for proper cam and lifter break-in. The general rule is to start the engine and immediately adjust the idle to more than 2,500 rpm. The break-in period is typically around 25 minutes long. Over that time, the idle is very gradually lowered and raised from 1,500 rpm to 3,000 rpm. Every manufacturer has a different version of this process and you should read the information included with your camshaft. The information written here is only a general idea of what the camshaft break-in procedure will be.
Fire It Up!
Now for the moment you’ve been waiting for. Don’t get ahead of yourself and relax yet; every engine needs two key things to run: fuel and fire. If you’ve followed all the steps, you should have plenty of fuel that can get to the engine, all your ignition parts installed, and the battery fully charged to power the spark or “fire.” Keep in mind that the best scenario is to start the car on the first try and to keep it running for the initial break-in period.
In order to safely break in the engine, it’s good to have at least one other person helping you watch the gauges for oil pressure, make sure the coolant temperature stays in the safe zone, look for oil and water leaks under the vehicle, and listen for strange noises. It’s always safer to have two sets of eyes and ears focused on the break-in process.
If you hear concerning sounds or see a problem at any point during the break-in process, shut the engine off immediately. After you’ve addressed the problem, re-start the engine and continue the break-in procedure.
The first thing to do after starting the engine is to get the RPM to the suggested level. Open the throttle to reach the correct RPM and adjust the idle screw on the carb until the engine sustains the breakin RPM. When you fire up the engine, it’s not going to be timed correctly. You’re going to need to turn the distributor to correct the timing soon after initially firing the engine. If you don’t, the engine could get damaged. At sustained break-in RPM, it can start overheating within a few minutes and cause the headers to glow red unless you correct the timing. There’s no way to use your timing light during this time, so you’ll have to time it by ear. Slowly turn the distributor until the RPM starts to climb and the engine is running effortlessly and then turn the distributor slightly clockwise to retard the timing. Correct the idle and continue monitoring everything. Once the suggested period of break-in time has passed, lower the idle to a normal operating level and set the timing and tune.
Roller Cam Break-In
Breaking in a roller cam is much easier than a flat tappet cam because the lifters roll on the cam lobe and don’t need to “matein” with the cam. Follow the instructions that come with your roller cam. Basically, you fire the engine and keep the idle at about 1,500 rpm for a few minutes while you check for oil pressure, leaks and noises, adjust the idle back down to normal, and then set the timing and tune.
Once the engine is shut off, let it cool. Check for leaks and loose hose clamps, hardware, belts, and accessories. Check the oil level and check to make sure there isn’t any white foam in the crankcase. If there is, water has somehow mixed with the oil and needs to be addressed right away. It could be water getting past the head bolt threads under the valve covers, or, it could be something more serious such as a crack in a head or the block. Pull the valve covers and look for beads of water around the valve springs. When you shut off a hot engine, pressure in the cooling system increases and coolant will try to find its way out. Check the coolant for oil residue when the radiator cools enough to safely remove the radiator cap. If the oil and coolant are in good shape you’re ready to move on. If you have an automatic transmission, start the car and check the fluid level. Top off the fluid level if it is low.
Crane Cams suggests changing the oil and filter after camshaft break-in and installing fresh nonsynthetic oil for the first 500 miles of engine break-in. For the rest of the next 5,000 miles of break-in, they suggest running non-synthetic oil. They consider 5,000 miles enough to fully seat the rings properly and synthetic oils can then be introduced.
Break In the Rest
Before hitting the streets at fullthrottle, you need to take it easy for the first 500 miles in order to make sure the piston rings seal with the cylinder walls. Without seating the rings correctly you will be plagued with low vacuum, blow-by, and loss of power potential. Take your vehicle out on the highway and drive it, without racing the engine, at highway speeds. Gradually fluctuate between the speed limit and slower speeds. Pull onto off-ramps to decelerate multiple times to promote ring seating under load and deceleration.
After the car has run for a few hundred miles, the rings start to seat and the tune needs to be adjusted and refined. The Barry Grant carburetor installed on the high-performance 496 engine came with a very informative DVD on how to tune your carburetor. If you want to know more about tuning your carburetor, CarTech’s S-A Design series offers tuning books on almost all carburetors on the market. They are a valuable resource and will be great for reference for years to come. There’s a good chance you’ll be making many changes on your car now that you’ve got a taste of the rewards of building your own engine, and just about every change can require a carb adjustment.
The best tuning tool on the market, without having your car strapped to a dynamometer, is the handheld Innovate Motorsports air/ fuel ratio meter. They offer a few different models. Some are stand-alone units and some have data logging and can be hooked up to a laptop computer for additional features. It reads the air/fuel ratio by hooking up to an oxygen sensor plugged into your exhaust system. This gives the user the ability to tune the carburetor and determine how the engine is running.
Written by Tony Huntimer and Posted with Permission of CarTechBooks