Low Compression on Cyl #2

[4G63SLEEPER]

Was up guys question I have 90 gsx just had my short block upgraded with 2g pistons and rings, new crank and rod bearings and new Oil Pump assembly with balance shafts removed. Sent out Head to checked and services with seals, etc. about 100 miles later I started having a miss fire. I checked all ignition system and fuel system all OK. did a compression test found #1 100psi, #2 24psi, #3 100psi, #4 100psi. I know thats not normal any ideas if its a ring issue in the motor or I have bent valve in the HEAD. any checks I can do to determine if its one or they other.

 

[DrHess]

Squirt some oil in the hole and do the compression test again. If it comes up (some), likely rings (or more likely, chunk of the crown missing). If it doesn't come up, likely bent valve. Either way, it's toast.

Dr.Hess

 

[cfisher]

All 4 are low compressionj #'s, not just #2. You should be over at least 150PSI on all 4. Time to tear her apart again my friend.