I was getting new plugs fitted to my 93 wrx. I decided to get a compression test done at the same time.

The readings on all cylinders was 125

The car has done 93k miles. Is this good or bad?

 

would have thought it would be more like 170+

 

Yes the readings are a little on the low side, was the motor upto temp ?

info for pre 97

981 - 1177kPa
10.0 - 12.0kg/cm2
142 - 171psi

Limit
834kPa
8.5kg/cm2
121psi

Max difference between cylinders
196kPA
2.0kg/cm2
28psi

 

I don't think it was up to temperature. The car was in the garage for 2 days. I was getting some electrical work done on it. It was definitely cold when they did the test.

The thing is the car has never missed a beat. Doing a search on here it seems a lot of people are getting the same sort of results, even though there are posts afterwards from people saying they're too low.

I would be intrigued to hear from these people to find out if their engine went bang shortly afterwards or anything?

 

as long as all four are similar compression I wouldn't worry.. especially if the engine was cold.

Simon

 

Mine came out at 155-170 across all four cylinders, 2000 miles after a rebuild. Standard 2.0 turbo.

 

You would need to do this test when the motor is up to temp to get an accurate reading. Based on that I am sure it will be fine as the rings expand the seal will be greater giving you less leakage and as you have said they all read 125, it would be a concern if there where quite different readings between each cylinder.