Compression test results

[BamaDave]

Finally checked my motor that has been sitting a while.

1=170
2=160
3=160
4=160
5=160
6=160
7=150
8=160

Does this sound good?

[BamaDave]

Meant to add a little truck shot

[50seven]

Those numbers seem fairly high? What compression ratio are your pistons?

But it is not the value that so much matters it is any noticeable difference in values between cylinders.

Unless you are noticing other problems like head gasket or valve guide issues which can play havoc with your numbers.

[geezer#99]

Originally Posted by BamaDave

Finally checked my motor that has been sitting a while.

1=170
2=160
3=160
4=160
5=160
6=160
7=150
8=160

Does this sound good?

Not perfect but nothing to worry about.
You want to look for a max of 10% difference between your high one and your low one.
Your high is #1 at 170. 10% of it is 17. Your lowest would ideally be 153 (170 minus 17) and #7 at 150 comes close enough.
All the rest are consistent.
An excellent motor.

[BamaDave]

Don't know what the piston ratio is. I know the heads are double humps. The motor is a 1969 out of a full size, what ever that means

[imjeff]

Looks good!

[50seven]

Your compression ratio of the motor determines what the numbers should.

A low compression motor 7.8:1 is going to have a lot less than 12.5:1 makes sense when you think about it right?

Atmospheric pressure is 14.7 psi so if you are compressing it 10:1 with your pistons..........then you know what your compression values should be. Now if any liquid either oil or water is in a cylinder even a small amount distorts your numbers because liquids don't compress.

If you are running double bumps those numbers are fairly close and fairly consistent so I would agree that motor looks good.