i have a gsr delsol...the car runs like a wrx...one cyilinder has no compression but still when i drive the car it still feels like it has full power...the higher rpms the car sounds good but low rpms while driving sounds like a wrx...could it possibly just be the oil rings on the piston? and the actual piston rings are still good? idk this never happened to me before...what about anyone else out there?

 

With no compression on a cylinder you are definitely not getting full power.

Have you done a leak down test, are you sure it not a valve that is not seating properly, I would definitely check valve adjustment, or look for possible bent valve. 94

 

No, the oil control rings do not seal compression at all and will not show up on a compression test.

 

Havent done a leak down test yet...but i have a feeling ur right bout the bent valves...i adjusted all the valves already but the car still runs rough...if the vaves were bent it would run like a wrx? i think the rings are still good cause when i give it full throttle i doesnt smoke out of the exhaust at all...

 

if the valves are bent you would definately notice

 

You most likely have a burnt or chipped exhaust valve since you have no compression at all in that one cylinder. In the case of the valve not seating correctly, you would still have some compression but you don't.

Also another thing, line up your engine at TDC to see if your timing belt possibly jumped.

 

yah im thinking the valve must be really bent or broken to have 0 compression on that cylinder...but if the rings were really gone it would smoke right? burn oil...

 

Not really, oil control rings have nothing to do with compression and compression rings have nothing to do with oil control. You could have perfect compression but bad oil control rings and burn oil like crazy. You could also have low compression due to faulty compression rings yet burn no oil.

A compression and leakdown test will tell you nothing about the condition of the oil control rings.

 

compression is 0...jumps up to 30ps and drops right back down to 0 as fast as it went up...doesnt smoke at all but i am doin a leak down test next...hopefully the rings are still good...it'll be easier taking the head off rahter than taking out the whole engine and rebuilding it...

 

i have the same problem, sound and all. today i did a wet and dry compression test for the problem cylinder #2 - got 57lbs dry and 45 wet (believe the drop means a valve issue) and a leak down test. cylinders 1,3,4 are good (around 20%) leak down test wise but 2 is around 80% leaking. i plan to remove the head and inspect all. i think thats the only way to tell.

 

OP: i had a chipped valve and kind of the same symptoms, but there was totally a loss in power. if ur gonna pull the head off anyway take another twenty minutes and pull that piston and check ur rings out. it will give you peace of mind anyway