Just did compression test: 145, 150, 150, 120. Retested the last cylinder twice at two different times, same result. So, is my engine shot? If so, how long can I drive before it gives out?

 

Poured a little oil in cylinder 4 and jumped up to 180! I guess it's the piston rings?

 

A leak down test will help you pin point the source.

 

rings possibly, try another tester you can see in one of my threads that my car was reading in the low 90s and it turned out the tester was ****

 

Yes.. If compression goes up when you put oil on top of the piston, it's most likely the rings.

 

I will try another tester also. Did the test this morning with the same tester and cylinder 4 (the one closest to battery) went up to 132? So now it's 145,150,150,132? I did notice the 132 was slowly "dropping" almost like a slow leak. Not sure if its the cylinder or the tester.

 

Even if the tester was in poor shape, it would show on the other cylinders. When doing a compression test consistency across the board is more important than the actual numbers. Seeing that your results were relatively the same when you did the test again I would rule out the tester and say that you do indeed have an issue in cylinder 4.

 

Throwing a leak down tester on there will let you know where the loss is occuring (valves, rings, etc.). It also lets you know how much leakage you have. 0 - 5% ideal, 5-10% good, 10-15% ok check for issues, 15+% what messed up?

I have seen 40+% loss on cars with busted valves.

I find the comp test good to let you know if something has gone wrong and make sure you are good across the board, but a leak down will give you a good idea of what is busted.

Sorry to sound like a broken record.

 

So, just back from the dealership. Their CP test result 150 for 1,2,3 and 4 was 145psi. They did a leak down test for all as well 8% across the board. The only thing I can think of is I perform the test wrong? Oh well, still good news...for now!

 

Compression/Leakdown tests can be fairly difficult to perform and get accurate results from (in my opinion anyway). I would take a combination of factors into account -- how long have you had the car? What kind of power modifications have been done and how long have they been placing additional load on the engine?

If your general impression on the car is that it is low on compression (which I am assuming is the case since you performed these tests), tests agree, and the car has 40,000 miles on meth/fpgreen I would look into at least a mild build. I know I have seen a lot of evo engines that have been taken care of decently (synth oil, decent tune, 350-420whp) begin to lose compression around the 70-90,000 mile mark.