1. Set tappets, adjust carburetor
and ignition timing as accurately as possible before starting
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.)
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
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.
Operate at one-half load or less
for the first two hours.