Comression test numbers

[soxnail]

I have a quick question for the brain trust...
I just ran a compression test and got the following:
#1 155 psi
#2 160 psi
#3 140 psi
#4 155 psi
The difference between highest 160 psi and lowest 140 psi is 12.5%, which is higher than 10% (number quoted often as being in specs).
My question is do I really need to tear into the head gasket/vales ect. for this differential ?
I don't wanna
Sox

[Arizona_928]

Throw some oil in number 3 and report back.

[Peter Graham]

Two things: Was the conmpression test done on a warm motor? Have you considered a leak-down test (will tell where compression is being lost)?

Peter

[soxnail]

Originally Posted by Arizona_928

Throw some oil in number 3 and report back.

Did the "wet" teaspoon of oil in the cylinder, compression went up to 180 psi...
Looks like piston rings ??
Sox

[soxnail]

Originally Posted by Peter Graham

Two things: Was the conmpression test done on a warm motor? Have you considered a leak-down test (will tell where compression is being lost)?

Peter

Test was done on a cold motor, Will do a leak down test next.
Sox

[Arizona_928]

Yeah. Rings are a little worn… almost a 40 year engine…

What’s your oil pressure? Burns oil?

[Arizona_928]

Originally Posted by soxnail

Test was done on a cold motor, Will do a leak down test next.
Sox

Is a waste if you got your compression up on a wet compression test. You know you don’t have a bad HG or burnt valves….

[soxnail]

Originally Posted by Arizona_928

Is a waste if you got your compression up on a wet compression test. You know you don’t have a bad HG or burnt valves….

concur, Will run a hot engine compression test after the car is running again.
Thanks
Sox

[dme]

Is it running badly? If not... let sleeping dogs lie.

[soxnail]

It's running fine, just chasing a 12psi boost issue...used to be 14psi.
Sox

[nize]

i'm pretty sure the lower boost is not because of the compression issue because i've seen 951's with even lower compression making over 21psi of boost.

[soxnail]

Nize, you are correct, it is not likely. I was just doing a general health check on the car. I also am getting the injectors cleaned and refurbished at the same time.
I am pretty sure the missing 2 psi are related to the massive leak at the ICV.
Sox

[80sVibes]

I just inked a deal on a new to me 89. I had compression testing done on it and it came back within 1% thank god. Gonna have a mechanic tear into it yet? ��