Did a compression check, engine was cold as I am mid-way through re-installing my Vortech. Not sure what to do now. I have been running N/A for about 5000 miles as I returned my car to stock a year ago. Car seems to run fine with no blue smoke or major oil loss. Car also ran great before I took the Vortech off last year. I had to replace the transmission and valve covers under a warranty hence the reason I returned the car to stock. On the one cylinder that was 100 I added a teaspoon of oil and it raised to 130. I am charging my battery to make sure I am spinning fast enough but I clearly have one cylinder that is low. Part of me wants to say f*ck it and just throw the supercharger on and see how long it holds up. The other is just sell everything, drive the car stock until I sell it. Advice?

150 140
150 160
180 100

 

This is probably a cracked ring land, so I wouldn't boost it any more... either part it out and sell it stock or plan on a shortblock.

Is it #5 or #6? Common issue since the most heat (and detonation) is in the rear.

 

With one at 180 anyone under 160 has a problem.

 

It's the #2 cylinder.

 

The 180 one could be a fluke, perhaps some oil from the valve cover dripped down into the cylinder when the plug was removed. At least on my Z I had that happen. Initially one read high but once everything dried out they all were 150-160 (130k miles boosted, so I think it's actually doing pretty well). If anything, I've got a low comp engine at this point lol.

 

Last time this happened to me it was a broken ring and it gouged the cylinder wall, ruining the block.

 

Update: I charged the battery and did the check again. The results were as follows

180 140
180 150
185 120

Still a significant difference on the #2 Cylinder so something is wrong. I agree it could be a ringland or a bent rod. Possibly a head gasket but there doesn't seem to be any symptoms of a head gasket issue. The car is not drive-able and in my garage so I don't have a way to do a leakdown test. I think I am going to pour some restore in it and hope for the best. If the motor blows I will just have a junkyard motor put in it and sell. Sucks that it has come to this but I'm not going to fall victim to the built motor twin turbo expense that many have gotten into. This may just be a perfect excuse to buy a used GT-R. I would hate to leave this platform and this car has given me many good years of fun. Guess I will see what happens.....

 

I am just curious..did you remove all 6 plugs while doing this test?