Engine Compression Check

The fact that the readings are within 5% of each other indicates the motor is in excellent condition, the static cylinder pressure of 150 psi indicates a relatively short duration cam with moderate lift and probably 9:1 CR Yes that's good

And somewhere around the time of 01/26/2004 13:28, the world stopped and listened as Mad Dog contributed the following to humanity:

Makes me feel much better about the condition of the engine. The last time I did a compression check was about 2-3 years ago and cylinder 1 read very low. But, that was probably due to the hand held guage that was used back then compared to the screw in type guage that I just used.

The plugs are well worn with what looks like a grey ash on the electrodes, so I put a new set of plugs in as well. That #3 plug you have to go through to wheel well to get to. Now, if I can figure out why my oil pressure is low, I'll have it made.

The crank main bearings hold the pressure, chances are the high mileage motor has worn the bearings down enough to lower the pressure substantially. the oil pump has also taken a beating from all the fine particles that get sucked up from the pan which the substandard oil filter failed to contain. Do a oil and filter change then listen carefully to the engine before oil pressure builds and you will probably hear a slight tapping or knocking for a moment indicating the bearings are "loose". Always prime the oil filter when performing a LOF and this will minimize the amount of wear on bearings from running w/o pressure while the oil filter fills with oil. A documentable amount of damage is done to a engine every time the oil and filter is changed because most techs don't care enough about a customers vehicle to prime the filter and/or disable the ignition until the oil pressure has been restored and all the bearings have sufficient lubrication.

-- Mad Dog