1. Set tappets, adjust carburetor and ignition timing as accurately as possible before starting engine.

2. Start engine and set throttle to an engine speed of approximately 25 miles per hour (trucks, tractors and stationary engines one-third throttle) until the engine coolant reaches normal operating temperature. Then shut down engine and retorque cylinder head bolts, recheck carburetor adjustments, ignition timing and valve tappet clearance. (Run engine at fast idle during warm-up period to assure adequate initial lubrication for piston rings, pistons and cylinders.)

BREAK-IN PROCEDURE

1. Make a test run at 30 miles per hour and accelerate at full throttle to 50 miles per hour. Repeat the acceleration cycle from 30 to 50 miles per hour at least ten times. No further break-in is necessary. If traffic conditions will not permit this procedure, accelerate the engine rapidly several times through the intermediate gears during the check run. The object is to apply a load to the engine for short periods of time and in rapid succession soon after engine warm up. This action thrusts the piston rings against the cylinder wall with increased pressure and results in accelerated ring seating.

2. Following the breaking-in, turn the vehicle over to the owner or operator with the following suggestions:

PASSENGER CAR AND LIGHT TRUCK

Drive vehicle normally but avoid sustained high speed during the first 100 miles.

HEAVY DUTY TRUCKS AND BUSES

If possible, place in light duty for first 50 miles. At no time should the engine be lugged. Lugging is said to exist when the engine does not respond to further depression of the accelerator.

FARM TRACTORS

Operate at one-half load or less for the first two hours.

(P33)