Have you had a break-in?
No, I am not taIking about a burglary, we are talking about breaking in a newly-rebuilt engine.
Sometimes the way people break in a new engine should be a crime. It is bad enough to spend a lot of money on a good rebuilt, only to waste it on a poor break-in procedure. It is even worse for a conscientious craftsman mechanic to spend many hours of special loving care on an engine that should last a lifetime come back with problems due to a poor break-in.
Of course, the owner will blame the mechanic and expect it to be taken care of under warranty. A lot of mechanics will take the time to put the first 100 miles or so on the car themselves, particularly on those old cast iron flatheads. Then they will give you specific instructions on the way they want you to break it in. I will be the first to admit—there are different theories on how to do this and there are a lot of old wives’ tales on how to do it.
You must also bear in mind that when the ’30s and ’40s cars were built, technologies, lubricants, fuel, coolants and experiences were far different than we have today. What your owner’s manual recommends for the break-in procedure was designed for a brand new cast engine and based on what they had to work with at that time.
Let’s assume that you have an engine that has just been completely rebuilt. By complete, I mean the block was completely boiled out, bored out and well-honed, all-new bearings, new pistons and rings, new valves and guides, the crankshaft turned, flywheel turned and the whole engine well-balanced as well as all the other goodies.
The mechanic probably had his own special blend of lubricant he used to put the engine together to protect it during those first few revolutions and few minutes of running. The engine is now in the car and ready to start to turn over. The crankcase has been filled with a light break-in oil and the radiator filled mainly with water with only a small amount of anti-freeze to lube the water pump.
Now with the coil wire disconnected, it is time to turn the engine over. Crank the engine over about 20 to 30 seconds and then let it set for the same amount of time. Repeat this several times, being careful not to overheat the starter. You should now have the oil well-circulated and should see some indication of oil pressure on the oil gauge.You should also have gas in the carb now and ready to start.
Now hook up the coil and turn on your electric fuel pump if you have one, and pump the accelerator a few times…then try to start the engine. When it does start, try not to let it race, but run it at a fast idle (about 800 to 1,000 rpm). After about a minute of running, shut it off and check for leaks. Assuming there are none, or if any, they are corrected, it is time to hook up your tach, dwell meter and timing light.
Start the engine again and let it warm up for awhile at around 900 to 1,000 rpm. As soon as it is warm enough to show on the heat gauge, you can do your preliminary carb adjustments and timing setting. After five to 10 minutes of running, shut it off and and let it cool about 10 minutes. This will give your engine a chance to absorb fluids through the normal expansion and contraction. Of course, you want to watch the temperature real close and not let it get hot, as this is quite possible on a new tight engine.
Again check for leaks. Now start the engine again and let it warm up to operating temperature. Now you can do your fine carb and distributor timing and let it run at a slow idle for 10 to 15 minutes. Shut it off and let it cool another 15 minutes. By now you should have all your leaks taken care of.
Now jack up the rear wheels, block the front wheels and start it again. After it has warmed up to operating temperature again you can rev up the engine a few times. You should get a little smoke out of the exhaust. It is now time to put the car in gear and let the rear wheels spin. Set it to run at about 30 mph for about five minutes and increase to 40 mph. Watch your heat and occasionally rev up and back off.
Let it cool again and repeat this process a few times until you have about 15 to 20 miles on the odometer. Let it cool and you are ready for a road test. This test should be about 20 miles with both stops and starts and highway driving. Try to get up to 55 to 60 mph for a few seconds and back off. When you get back to the garage and the engine is still warm, retorque the heads and let the engine cool to stone cold.
You are now ready for your first highway break-in. Check all your fluids and take the car out on the open road. Once it is up to operating temperature, slowly accelerate to 60 mph. Watch your heat closely. If it starts to heat, slow down. If it gets real hot, stop and let it idle about 30 seconds and then shut it off and let it cool for 15 to 30 minutes. Check your fluids again and start up and be on your way. Continue your drive to at least 100 miles. Keep varying your speed and quite often let your foot off the gas, letting the car slow down against compression to about 35 mph from 60 or so.
Near the end of your trip, try to hold a steady 55 to 60 mph for five miles. When you get back, let the car idle for two to three minutes, rev it up to about 2,000 rpm, then shut it off. After it has cooled a bit, it is now time to drain and change to a good-quality oil. Then flush out the cooling system and install the proper mixture of anti-freeze.
You are now ready to enjoy your “new car.” During the next 1,000 miles, the more highway miles you can put on it, the better. Varying speeds and occasional high speeds are good, but remember to frequently back off against compression to allow good internal lubrication and remember to slow down if it starts to heat.
Do not let a new engine overheat. Stop and cool down if you must. Sometime between 500 and 1,000 miles, you will want to check and reset your timing and tune the carburetor slowing down the idle. You should also recheck the torque on the head bolts and put in new spark plugs. If you break in your engine at only low speeds, you will find that at highway speeds your car will tend to overheat very easily.
You should have many enjoyable and trouble-free miles from here on. Life is good when you have an old Cadillac, but even better if you are fortunate enough to have a LaSalle.
See ya next month.