ever since i built this motor, the #2cyl has had low compression. (9:1 static). it started at 165 or so (180 for the other 3), and now its down to about 115 over like 8-10k miles and about 20 track and 10 dyno passes.

leakdown shows well over 50% out of my exhaust valves in that cyl.

when i do a wet compression check it goes up from 115 to just about 150.

i know for a fact i have exhaust valve problems, but are my rings also shitting out contributing to it?

im making nowhere near the power i should (1bar boost, t3 60-1 on a fully built lsvtec 320whp), but i never have been.

 

even if you have good compression, won't adding oil make it higher? My point being that you should fix the ehxuast valves first, then check it out. Are they lashed properly?

 

beyond the valves and rings you could have a cylinder that is out of round. Putting new rings in may not solve the problem. You have to measure the cylinder and cannot judge it by eyeball.

 

your best bet is to pull the head off and have the exhaust valve fixed then slap the head back on and check the leak down and comression again.
you should get it fixed soon and not drive it. your basically running on 3.5 cilinders, which is why your numbers are so low. i make 400whp 300 tq on my 2.0 9.1 cr t3 60-1 on 12-14 psi

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by earl &raquo;</TD></TR><TR><TD CLASS="quote">beyond the valves and rings you could have a cylinder that is out of round. Putting new rings in may not solve the problem. You have to measure the cylinder and cannot judge it by eyeball.</TD></TR></TABLE>

hmmm interesting. when i replaced the hg at the beginning of the summer, it almost looked as if i can see more of the piston ring around the #2 piston than any other cyls, almost like the bore was a lil big. probably not the case, but i thought id mention.


<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by riceball777 &raquo;</TD></TR><TR><TD CLASS="quote">you should get it fixed soon and not drive it. </TD></TR></TABLE>
haha probably true. im gonna take it to englishtown for fall nationals. the motor runs as strong now as ever, regardless of how bad the compression is. im probably being a dick by doing it. that cyl has always had terrible leakdown from the first check i did with like 1000 miles

 

with such bad leak down does the engine burn a lot of oil and smoke a lot?

 

it burns 0 oil. i do consume a small amount of coolant every now and again. it smokes a tiny bit, but some of it is black from extra fuel....

 

are you the origional owner? if not it's possible the old owner had a problem with that piston (broke it on boosting) honed the cyclinder out to clean it up and went a little too far on it. so when you repaled the rings again it jsut caused them to be that much worse and it's not sealing properly.

is the pistons rings properly positioned?

check valve lash. to tight can cause the valve to remain open.

bad valve job on that cyclinder can cause the valves not to seal and have this issue too.

good luck.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by oscarmayer &raquo;</TD></TR><TR><TD CLASS="quote">are you the origional owner? if not it's possible the old owner had a problem with that piston (broke it on boosting) honed the cyclinder out to clean it up and went a little too far on it. so when you repaled the rings again it jsut caused them to be that much worse and it's not sealing properly.

is the pistons rings properly positioned?

check valve lash. to tight can cause the valve to remain open.

bad valve job on that cyclinder can cause the valves not to seal and have this issue too.

good luck.</TD></TR></TABLE>


im the original owner of this build. i drove the block to z10 for sleeving and drove back to jersey to pick it up. the block has been fully redone(jeez it cost me like 3k probably).

i had loosened the lash, and solved some leakdown out of my #3 cyl, but not out of #2.

thanks for the good luck man . ill probably wind up rebuilding it entirely, maybe with some 84mm in mix . just kinda trying to see what im gonna be dealing with