Compression Test Numbers...

Compression Test Numbers... - 04/30/10 12:41 PM

The engine is a 68 318 with supposedly around 182k miles on it? Let me know if you have any feedback. My results were as follows:

Cylinder
1= 135
2= 135
3= 145
4= 150
5= 135
6= 145
7= 140
8= 150

Thanks in advance

Posted By: RapidRobert

Re: Compression Test Numbers... - 04/30/10 01:37 PM

Fairly high consistent readings. You're in good shape esp w that many miles

Posted By: Dodgem

Re: Compression Test Numbers... - 04/30/10 02:09 PM

Great I once put 360 heads on a well used 78 318 in my truck and it had 100 to 110 would pull my car and trailer with ease and run 15's in the quarter. LB4B intake 750 Vacuum holley headers and an erson cam.
Do the timing chain for sure.

Posted By: OrangeProwler

Re: Compression Test Numbers... - 04/30/10 10:07 PM

Thank you. I just wanted to make sure I didn't have too much variation on the two cylinders. I guess while I'm at it; what type of numbers does a freshly rebuilt engine have for compression just out of curiousity?

Posted By: RapidRobert

Re: Compression Test Numbers... - 04/30/10 10:15 PM

Quote:

what type of numbers does a freshly rebuilt engine have for compression just out of curiousity?

maybe ~160-200 depending on the static CR and the cam

Posted By: Kern Dog

Re: Compression Test Numbers... - 04/30/10 11:11 PM

As mentioned above, the compression numbers for a fresh motor can vary. The numbers will be high with a 10 to 1 motor with a totally stock cam. Put in one designed for performance, and the overlap and long duration bleed off pressure and the compression test will show lower numbers.

ALSO..... Most repair and service manuals state that anything LESS than 10% variance between the highest and lowest cylinders is acceptable for a street engine, and is a better guide to an engines condition than any specific number.