Compression test: ~120 across??

[4G63 For Me]

After doing a rebuild about 5000 miles ago and putting in JE pistons and Eagle rods, my car is sputtering under boost now and there is oil on plugs 1 and 3. I did a compression test and all 4 cylinders are at 120-125. What the dealio? I've read if it's the head gasket, only 1 or 2 numbers will be low. Why are they all pretty much the same? Could the rings for all the pistons be messed up that equally, after so few miles? Break in was done properly, regular Penzoil 10W/30 was used for the first 1000, then Mobile 1 10W/30 synthetic since.

Car was warmed up a bit before testing (the temp gauage was in the middle), the gas pedal was floored, it was really cold outside, didn't do the wet test. I could probably determine the problem from a number or two being really low, but all of them were VERY equal. Is it a possibility I did the test wrong? Where should I go from here?

Thanks in advance for your help.

Oh, I was doing some searching and it seems that at 5000ft of elevation (where I'm at), if normal compression should be 160, I should be at 132.8. Now, with my setup, I should be running about 180 (or 150 corrected), right? So 120 would still be low. Ick, I'm getting a headache.

 

[4G63 For Me]

I guess one of the problems is I don't really know what my compression should have been. I tested it when it was around 20 degrees outside, at 5000 feet. Does anybody know what it should have been?

 

[johnk]

Are the pistons higher compression? Did you get results on the wet test?

 

[myblack98gst]

try to find another gauge to compare the readings too it could be broke.



when you were cranking for the test, how many strokes did you let it go. sounds like you only did one.. I am fairly certain you are supossed to go four strokes or untill the gauge maxes out. I always do mine at 4 though

 

[el aguila]

Do a leak down test so we can pinpoint exactly where you are losing compression.

 

[el aguila]

try to find another gauge to compare the readings too it could be broke.



when you were cranking for the test, how many strokes did you let it go. sounds like you only did one.. I am fairly certain you are supossed to go four strokes or untill the gauge maxes out. I always do mine at 4 though

You want to crank the engine for 5 revolutions. Look at the first and fifth "puffs" on the gauge.