hi guys i have s2 turbo 1660cc with low compression mahle pistons and rings and my mate done a compression pressure test on the engine and it was only reading at 90psi dose this sound to low if so dose this mean the piston rings are fooked?

 

90psi is low.Surprised its running,lol. Warm the engine up,do another test,wind it over for about 5 secs and equally for each cylinder. Is each cylinder 90??

 

3 of the cylinders are 90psi but the other one is only 80psi the car is running fine but when we did the test the engine was cold

 

to tell if it is your piston rings that are knackered get an oil can and put 3/4 good squirts of oil in each cylinder before you perform the test, if the reading on the compression tester rises significantly then they need replacing.
the oil has this affect by sealing the rings, will burn off as soon as you start up again.

 

Tbh m8 90 is far too low. You want to be looking at 10 bar(140psi) minimum.
As above with regards to checking basic ring/bore wear. Each cylinder should rise by the same amount +/- a wee bit.

 

When you test it did you push throttle pedal to floor??




john

 

no mate i did not push the throttle pedal to the floor why should i have

 

When i was apprentice years ago was told when doing compression test to put pedal to floor when cranking.

On my old low comp rst engine it made 150psi on all cylinders.



john