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Bonehead move on compression test

RFSchaller

Well Known Member
I'm doing the 5 year rubber replacement, so I have a lot of stuff removed to gain access to hoses. That includes the oil tank. Yesterday I decided to do the compression test with the oil tank hoses disconnected. Bad decision! Blew oil all over the place! Pretty good lesson on the effectiveness of piston ring blow by as opposed to a scavenger pump!
 
I'm doing the 5 year rubber replacement, so I have a lot of stuff removed to gain access to hoses. That includes the oil tank. Yesterday I decided to do the compression test with the oil tank hoses disconnected. Bad decision! Blew oil all over the place! Pretty good lesson on the effectiveness of piston ring blow by as opposed to a scavenger pump!

What No Pictures?:eek:
 
Are you cranking the engine or using differential-pressure tester?

DP is much safer and allows better diagnostics to determine if leakage is ring or valve related...
 
Yes, with the DP method, a loud gurgling (as occurs when the 912 engine is "burped") is audible when the cylinder is pressurized (just remove the oil tank cap to hear it quite clearly).
 
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