Page 1 of 1

Compression testing

Posted: Sun Dec 22, 2013 12:32 pm
by 4.6_crossbolt
While hunting for the cause of a non-firing cylinder on my Scimitar's Rover V8 (prefix 11A - cr 9.35:1), I did a set of dry compression tests - the results of all eight were between 140-150 psi.

Is that figure reasonable? I know a difference of about 10 psi is nothing to worry about, but I was curious as to what figure I should expect.

Incidentally, the non-firing turned out to be a sooted-up plug which occurred during setting up a four SU installation on a Boxer manifold - a somewhat tedious and complex procedure.

Posted: Sun Dec 22, 2013 1:07 pm
by SimpleSimon
They are similar to what I got with a serp 3.9 with the same CR with a spikey cam I backed this up with a leak down test which gave very good results for a high mileage RV8 8-)

Posted: Sun Dec 22, 2013 5:25 pm
by ChrisJC
I tend to concern myself with all readings being similar, rather than what the readings actually are.

Chris.

Posted: Sun Dec 22, 2013 6:30 pm
by 4.6_crossbolt
Thanks for the information - I have no idea of the engine's history, so can only guess at the mileage, but I imagine it's fairly high. The results seem reasonably encouraging that I'm not facing a rebuild just yet.

Posted: Sun Dec 22, 2013 7:00 pm
by SimpleSimon
ChrisJC wrote:I tend to concern myself with all readings being similar, rather than what the readings actually are.

Chris.
+1 8-)