Bri Bro

At 2500 ft your air preasure has drop by 9% from sea level, so multiple your readings by 1.09.

dand86951

OOps sorry no I didn't mean I had lost the dowel pin more than once, just that I have done a leakdown test. Never did lose a dowel pin and when you use the rotor to indicate which cyl you are on TDC, then you really don't need the dowel.

dand86951

Not the compression test as that is a dynamic test. The leak down test is static and can be done anywhere in the stroke that all the valves are closed. The taper is checked by using a dial bore gage. It is just that at some point slightly lower than TDC you may see the leak % go up and you could hear it through the oil filler. Then you would have a bit of an indication that your rings seal better at tdc than they do lower down. This could be caused by a larger clearance at the bottom of the cylinder than the top.

Fluidplay

good idea mtnman... i'll hook up the tester directly to the compressor, just to see if it is showing the same psi. By the way i'm at sea level too. South O.C. CA. Does anyone have any data on compression tests at various altitudes?
Side bar thought... trying to remove the crank pully on a different 951 engine with a 735 lb impact wrench and it's not budging. ideas anyone? appreciate all the help!!

Bri Bro

The preasure decreases with altitude, amazing anyone could live/breath at the alitudes of Everest, 4PSI

http://www.sablesys.com/baro-altitude.html