Restoring your flathead

Part 8—Gentlemen…start your engines!

Starting up your newly-restored flathead is usually a very thrilling experience. Most likely several friends and Club members have said, “I want to be there when you fire up that baby!” You may want to rent the local football stadium and charge admission.

The best advice I can give is to be patient! Whenever you fight a deadline, you will find out they fight dirty and usually jump up and bite you in the butt.

Assuming you are doing a full restoration, you should either have new wiring, or you have fully checked each and every circuit. Fires are no fun.

After the electrical systems have all been checked out and are in good shape, it is time to check out all of your coolant plumbing, all your hose connections, etc. Fill the cooling system with water (not anti-freeze at this time). Make sure all the heater controls and valves are fully open.

Oops! You forgot to tighten your block drains and water is running out. Aren’t you glad it isn’t anti-freeze you are standing in? Check for any other obvious leaks at this time. This isn’t the only reason to use only water at this point in time as you will see why later.

Hopefully you have installed filters in your upper radiator hoses. It seems that no matter how much you have cleaned and flushed the water jacket in the block, there will always be some dirt and/or rust come loose in the first couple hours of running the engine.

Very good—you don’t see any water leaks at this time, so let’s hook up and check out the fuel lines and related plumbing. When it is checked out, tightened and fresh gas is in the tank, run the auxiliary fuel pump and fill up the lines and carburetor.

If for some reason you don’t have an auxiliary fuel pump, make sure the coil wire is disconnected and turn the engine over a few times with the starter. Look for any leaks in the fuel system and while the engine is cranking, listen for any unusual noises. Check for any oil leaks and top off the coolant again. Check the oil level again and check for any oil leaks just to be sure.

If you have shutters on the radiator, disconnect them and tie them open for now. Hook the coil wire back up. You should also have a tach/dwell meter hooked up. Be patient and check everything again. When you are satisfied, it is time to start your new engine (after a short prayer, that is).

It is best to use a remote starter switch and have someone in the driver’s seat to be on the ignition switch, just in case. Turn on the key and, with the electric fuel pump on, crank the starter and pump the foot feed. This is the moment you were waiting for and when it fires up, don’t let the engine rev up any higher than 1,000 revolutions per minute (RPM).

If it doesn’t fire up on the first try, after a short time, observe the tach/dwell meter to make sure you are getting fire to the spark plugs. Then check for fuel in the carburetor. Assuming it fires, it will run rough for a few seconds and then smooth out. Set your idle at about 900–1,000 RPM and check everywhere for any kind of leaks. If you have any leaks whatsoever, stop the engine, correct these leaks and clean up any spills before going on.

If all is okay, or corrected, start again and run for about two minutes. Don’t get panic-stricken if you have some oil smoke out of the exhaust at first. This is to be expected. Not only will you get some smoke out of the exhaust, you will smell a little paint burning from the various areas in the engine compartment.

Start it again and let it run at about 1,000 RPM for another few minutes. Keep checking your temperature gauge and all over for leaks. You should be running smooth by now, so cut down your RPM to about 750–800 and start adjusting the low-speed jets on the carburetor one at a time, back and forth, watching the tachometer get the maximum RPM from the current throttle setting.

Don’t think you can set these by sound; your ears aren’t that good. Now drop the RPM to about 600 and set these jets again. When you are satisfied that you have the maximum setting, shut off the engine and let it cool for about 5 minutes or so. Start the engine a few times and check for easy starting. After a minute or so, set the RPM to about 1,250, keeping watch for leaks and heating.

Remember, you have a new and tight engine and heating will be normal for awhile, so don’t let it overheat. If you aren’t overheating, let it run for five to 10 minutes and slowly vary the RPMs from 600 to 1,500. Stop the engine and let it set and cool for about one-half hour.

Now check your water and oil level. Then take the next very important step. Retorque your cylinder heads to 75 ft.-lbs. This is something you will be doing at least six times over the next 25 hours of running your new engine. Failure to do so can easily result in blown head gaskets and/or warped heads.

Time to get out your timing light and start up the engine. Once it gets up to running temperature, set the timing as mentioned in previous articles and your service manual.

Now that your engine is tuned and timed, put a floor fan in front of the radiator and run the engine about 30 to 45 minutes, varying your speed from idle to 2,000 RPM. This is done to prevent a sharp ridge from forming at the top of the cylinder walls.

Oh, I know you want to take it for a drive, and you probably will regardless of any advice I or anyone else might give you. But you should let the engine cool down completely and retorque the head bolts again. Check and/or clean your coolant filters and flush your cooling system and refill will fresh water.

Are you ready for your first drive? I thought so. Try to get to open highway as soon as possible but don’t go too far. Drive as long as you can at varying speeds until you start to heat. Don’t let it overheat; pull over and let it cool down.

As you are breaking in your new engine, you will find that you can go longer and longer before it starts to heat up. During this period, change the water often and clean your coolant filters. Don’t forget to keep checking your head bolt torque. Also check your oil a few times as you will likely use a little during break-in.

After about 500 miles, change your oil and drain out all the water. Then put in your mixture of 50/50 anti-freeze and purified water.

Life is now good, and hopefully, you need to have a hat two sizes larger for your swelled head over the good job you have done.

Drive and enjoy before mad car disease strikes you again and you start looking for another project car to start all over again (family and spouse permitting).

See ya next month,

—Walt