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View Full Version : Compression test results. Please advise.



Jivepepper
07-15-2008, 10:04 AM
I took a compression test and had a couple questions about the results.

I did this on a warm motor with the throttle body open cranking about 3 times per cylinder. Maybe I should have turned it over a few more times?

This is the results


Rear of motor
124-125
125-125
125-124
125-126

My pistons are 18cc and with a stock head the c/r should be 9.0:1--8.9:1.

But I have added Stage 2 heads with the swirl dams removed with the combustion chamber increased. I also have Hp cams with 531 lift. 114lsa and 240 duration. 292 duration advertised.

I like how close the numbers are. But what about the cranking pressure?

Wolfpack Speed
07-15-2008, 10:11 AM
crank a minimum of 5 times, but really until the guage stops rising...then thats your number:awsome:

Jivepepper
07-15-2008, 10:29 AM
Well I cranked it 3 times and went out and looked. I borrowed the gauge so I hope it's ok.

Wolfpack Speed
07-15-2008, 11:13 AM
Well I cranked it 3 times and went out and looked. I borrowed the gauge so I hope it's ok.
thats not going to cut it, either position the guage through your hood on your windshield so you can read it while cranking or get another person to help you...

Jivepepper
07-15-2008, 11:19 AM
Thanks.

Rodeheaver's
07-15-2008, 11:32 AM
dude... the guage you used stores the compression until you release it.. and if you are not getting your number by 3 spins then forget it!!!! if you remember you did that one cyl like 5 or 6 times and it was no different than the others.. you want to try and turn it over the least amount of times possible if you are trying to find a problem, so 3 times is perfect, it will present a problem plain as day..

Wolfpack Speed
07-15-2008, 12:55 PM
dude... the guage you used stores the compression until you release it.. and if you are not getting your number by 3 spins then forget it!!!! if you remember you did that one cyl like 5 or 6 times and it was no different than the others.. you want to try and turn it over the least amount of times possible if you are trying to find a problem, so 3 times is perfect, it will present a problem plain as day..
yes the guage stores compression but if you haven't built up enough compression it's only going to show what you have to that point. you must keep cranking until the guage stops for an accurate reading...