eschneider
Jedi Warrior
Offline
OK, so I need some help from the "old injuns" in the crowd.
I'm working on an engine (4 cylinder) that I know has some ring wear. It is burning some oil, no question. I did a compression test and a leakdown test, both warm and cold.
Compression test numbers were dead even across the board at 85-90psi (cold engine). Numbers verified with 2 differwent gauges. Values actually went down about 5PSI when re-tested on a hot engine. This engine has a way radical cam, somewhere in the 300 duration range, so I'm not as concerned with the low values.
The part that has me scratching my head is the difference between hot and cold testing using a leakdown gauge.
COLD testing resulted in 30-35% leakdown on each cylinder. Eeek.
with the engine HOT, leakdown went to 7-10%. The gauge is the type that is calibrated at about 3%, so these numbers are better than they should be......
That's a HUGE difference, and I have my theories, but I thought perhaps some of you more experienced guys might have seen this before....
PS - on the cold test, leakage was definitely past the rings (audible leakage at the dipstick / oil filler cap) but surprisingly NOTHING, NADA, NIL, ZERO through the exhaust or intake, or via adjacent cylinders......
I'm working on an engine (4 cylinder) that I know has some ring wear. It is burning some oil, no question. I did a compression test and a leakdown test, both warm and cold.
Compression test numbers were dead even across the board at 85-90psi (cold engine). Numbers verified with 2 differwent gauges. Values actually went down about 5PSI when re-tested on a hot engine. This engine has a way radical cam, somewhere in the 300 duration range, so I'm not as concerned with the low values.
The part that has me scratching my head is the difference between hot and cold testing using a leakdown gauge.
COLD testing resulted in 30-35% leakdown on each cylinder. Eeek.
with the engine HOT, leakdown went to 7-10%. The gauge is the type that is calibrated at about 3%, so these numbers are better than they should be......
That's a HUGE difference, and I have my theories, but I thought perhaps some of you more experienced guys might have seen this before....
PS - on the cold test, leakage was definitely past the rings (audible leakage at the dipstick / oil filler cap) but surprisingly NOTHING, NADA, NIL, ZERO through the exhaust or intake, or via adjacent cylinders......