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mooney265 mooney265 is offline
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Join Date: Sep 2008
Location: New Orleans
Posts: 1,365
I've done compression tests before on anything from lawnmowers, mercury outboards to nissan 2.0 liters... So, I've got the compression test thing figured: Disconnect coil and fuel pumps, pull spark plug, insert compression gauge, turn engine over, read gauge...

The one thing that I can't seem to wrap my head around, however, is how do I pressurize each cylinder for a leakdown? And, how do I align each cylinder for the test?

When folks use numbers like 3% leakdown... What does that mean:

3% leakdown after 1-minute? or,
3% leakdown after 5-minutes? or, 5-seconds???

LIVN80S - - Red '79 Porsche 930 Steel Slant Nose Conversion [in 1987] w. 46k miles 3.3L; 964 Cams; K27HF @ 1.0 BAR, with Garrettson Intercooler; Rarly Zork; CIS Flowtech Fuel Head & BL-WUR.

Last edited by mooney265; 06-19-2010 at 06:02 AM..
Old 06-19-2010, 05:59 AM
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