Compression test results
Thread Starter
Instructor
Joined: Jun 2004
Posts: 235
Likes: 0
From: NE
Compression test results
Compression test on newly rebuilt motor. All cylinders are around 145-150 except #3 which is at 120. I squirted a little oil in that cylinder and tried another test but it is still at 120. Would these mean it is one of the valves rather than the piston rings that are leaking on #3?
It has quite a bit crank case pressure. If one of the valves was leaking could this cause more crank case pressure?
It has quite a bit crank case pressure. If one of the valves was leaking could this cause more crank case pressure?
Race Director
Joined: Sep 1999
Posts: 11,361
Likes: 383
From: Plano TX
Seems like you have 2 problems. A leaky valve on #3 and rings that don't seal well on all(?) cylinders. The valve could be something really simple as an overtightened rocker.
As for the crankcase pressure, if you can fix the valve I'd drive it and see if it gets better. Piston rings should seal within the first hour of runtime, but should and will are not synonyms.
As for the crankcase pressure, if you can fix the valve I'd drive it and see if it gets better. Piston rings should seal within the first hour of runtime, but should and will are not synonyms.
