Help me diagnose blown S50?

[golde30]

hey guys, so i have my blown s50 out of my e30 on a stand. the issue is:
-very low (15psi) compression on 1/2,
-kinda low(160psi) compression on 3/4,
-low (80psi) on 5/6.
test done with motor dead cold.

i have the engine stripped down to head/block only rite now, and i decided to do a ghetto leak down test, which means i used a pressure tester hose, and hooked up compressed air (30psi), and did 1 cyl at a time each at TDC. so now,
-cyl 1/2 i can feel the air passing between cylinders. ok, head gasket bad.
-cyl 3/4 i can hear the air escaping into the block, bad rings?
-cyl 6/6 i can feel very little air passing between cyliners, and also a little air getting into the block as well.

so do i have a bad headgasket AND bad piston rings? seems pretty strange... maybe the motor was just beat. the head gasket was fairly new, like within 10K miles. car did not overheat..

[328ijunkie]

are you making sure each cyl is at TDC when you do the 'leak down' test? Blowby to the crankcase is normal... In small amounts.
If you have cross pressure between 1/2 you prob blew out the fire ring on the HG.
Overrev it by chance? Failed retianers? could be a few things. Either way head has to come off.

[golde30]

I did over rev the motor, but that was before I rebuilt the motor last time. Head was rebuilt as I bent all the exhaust side valves. Just seems strange that the headgasket went for no reason. Guess I will pull the head and get it pressure checked again. This is my spare motor now, as I am running an s52. Just don't wanna junk an s50, but also not gonna dump more than $1k into rebuild, not worth it.