3-92. ENGINE DYNAMOMETER TESTING (Contd)
Lubricating oil pressure should remain at or near a constant figure at constant engine
speed and load after normal operating temperature is reached. Acceptable lubricating
oil pressures are 5-20 psi (34-138 kPa) at idle speed and 35-45 psi (241-310 kPa) for Big
Cam III and 40-75 psi (276-517 kPa) for Big Cam I at rated speed. Abnormally high
pressures may indicate blocked lubricating oil lines. Abnormally low pressures indicate
an insufficient supply of lubricating oil from the pump or increased engine clearances
which may be due to bearing failure. Damage to engine may occur if oil pressure falls
outside of acceptable range at indicated speeds.
Lubricating oil temperature must not rise sharply above 225°F (107°C). Shut down
engine and correct as necessary. Damage to engine may occur if oil temperature rises
above acceptable limit.
Check temperature of coolant. Temperature should not exceed 200°F (93°C) or drop
below 160°F (71°C) during engine tests. Do not turn engine off immediately after a load
run. Heat stored in engine will boil coolant in the water jackets if air and coolant
circulation are immediately stopped while engine is hot. Allow engine to idle a
minimum of three minutes before shutting down.
Do not idle engine for prolonged periods of time before completing break-in running.
b. Break-in Running
Start engine (8) and check oil
Idle at approximately 1200 rpm
pressure, oil temperature, and
no-load for 5 to 10 minutes.
water temperature. Check for leaks.
Operate air compressor (7) in