Model A Garage, Inc.

Restoring history one car at a time

Engine Break-in Instructions

The Model ‘A’ engine has a 5-quart capacity. Before you attempt to start your newly rebuilt engine it is necessary to add oil. Your engine will give years of service if you follow these instructions. There has been a lot of view points expressed regarding the best oil to use in you engine. Since it has been rebuilt, it is recommended that 10W-30 oil be added to the crankcase. If your engine was installed at our facilities we have used and recommend Mobile 1 synthetic 10W-30.

If you are adding oil for the first time begin by putting 4 quarts in the crankcase thru the engine fill/breather tube on the left side of the engine. Remove the distributor and add the fifth quart through the hole in the top of the head. This ensures that the main bearings and the valve guides will be properly lubricated during the initial start up.

Before Start-Up:

  1. It is important that the distributor and carburetor are also rebuilt or otherwise in good working condition. This will ensure that your newly rebuilt engine will perform as expected.
  2. Check the cooling system to make sure that the radiator has been topped off. Do not over fill. The coolant should be just above the baffle when looking into the radiator from the top.
  3. The manifold and muffler should have a proper fit with no leaks to make  be resurfaced as a matched pair, intake and exhaust. If the engine was installed at the Model A Garage this has already been done. Having this done also lessens the chance of a cracked manifold since the manifold will not be stressed when bolted to the engine.

Starting the Engine For The First Time:

CAUTION: During the break in period do not place a heavy strain on the engine. If you follow the break in instructions below, you can expect long engine life.

Run the engine for a period of ten to fifteen minutes, just above idle with the spark half advanced. After ten to fifteen minutes of running, allow the engine to cool down. Repeat this process for a total of two hours running time. Blue smoke may appear at the tail pipe. This is because the piston rings are not seated. The piston rings can take up to 1000 miles to seat to the cylinder wall.

For the third hour of stationary engine running, increase the period of running time to 20–30 minutes with the spark half advanced. Engine acceleration during this period is acceptable with momentary bursts of increased RPM returning to just above idle.

For the third hour of stationary engine running, retorque the head to 50/55 foot lbs. Use the proper torque sequence. (The head gaskets tend to compress during the engine warm-up.)   An oil change is also suggested at the time. (10-30W oil) Mobil 1 synthetic recommended

If the engine was installed at our facility we have, more than likely, preformed the stationary break in for you. Check with the service department to be sure.

Ready For The Road:

If the initial three hours of running time is completed without the engine stopping and/or excessive heat, you are ready for the open road.

After 200 miles, not exceeding 35 MPH, an oil change is necessary. (10W-30 oil) Mobil 1 synthetic recommended

Full break-in may not occur until 500 miles have been put on the engine, depending on driving conditions. During this time, keep your speed at or below 35 MPH.

Oil changes should be made every 500 miles or every driving season, whichever comes first. Remember to use (10W-30 oil) Mobil 1 synthetic recommended.


Model A Garage Inc

Service Department

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