rings bad?

[ryant102]

i did a compression test last night. all i did was pull all plug wires off i didn't remove any plugs exept the one i was testing at the time i did not pull the mpi fuse and did not hold the throttle down. i didn't know about this procedure untill just reading up on it. my results were 148 145 140 138 from left to right. are these bad numbers? i know the service limit is 121 but im still wondering how bad that is due to the fact im starting to order things for my 16g build. also my valve seals are bad, do not know if that would cause low compression. i was told by a friend of the kid i bought it off of it had recently had a head gasket. so i don't believe its bad. also has clean oil and no loss of antifreeze.

 

[BogusSVO]

valve seals have no bearing on your compression

 

[DSMnoobsause]

your comp numbers look fine if thats a cold comp test. what are the reasons you are doing this? does it run bad/ smoke? also was that cold engine or hot? you should do a hot comp test.

 

[motozachl]

If you put a cap of oil in each cylinder then redo the compression test and your numbers go up, then your rings are showing signs of wear. Otherwise your numbers don't look too bad.

 

[ryant102]

your comp numbers look fine if thats a cold comp test. what are the reasons you are doing this? does it run bad/ smoke? also was that cold engine or hot? you should do a hot comp test.

i was just testing to see what they were i purchased the car about 3 weeks agoand im just going over all bases. it does smoke and if i let it idle for like ten minutes it smokes like crazy when i start moving. i was told it was valve seals and i have them just need to replace them.

 

[xI Dsmman Ix]

Easiest way to tell if its valve seals is remove the spark plugs and check for a oily residue, Currently my car is smoking like crazy and I need to run a compression test because it looks to me like the valve seals are fine.

 

[And_44]

Those numbers look okay especially for a cold test, as your engine heats up the components expand and close the gaps so on a hot engine those numbers should be higher. I do believe that the numbers have to be within 25% of each other too (not 100% on percentage but stated in manual).

Valve seals do effect a compression test. They seal the top of the cylinder on the exhaust and intake ports. With leaky seals air escapes and oil can get in from the valve area. You cannot tell bad valve seals by pulling spark plugs. Valve seals will leak into the compression cylinder not the spark plug wells. Bad rings or seals will put residue on your plugs but that's pointless since you already know from the exhaust that your burning oil.

If your car is still together warm it up to operating temp and do the test again, and record those numbers then put about a cap (a 1 quart oil cap) of oil into each cylinder and do the test again, this is a wet test. If the numbers are higher your rings are leaking, if they are about the same your rings are fine.

Now for the smoking. You mentioned that if you let the car sit for a few minutes at an idle and apply gas it smokes that's common for bad valve seals. Why this happens is that as your car idles the oil is allowed to "puddle" around the exhaust valve's and when gas is applied the oil is burned from the exhaust temps in your exhaust.

Bad rings will smoke at idle and cruise all the time basically.

Valve seals are somewhat easy to replace. You can do it with the head still installed on the car, I'd be cautious though and where safety glass's. You'll poke an eye out with this job if not careful. There is a few write ups on doing this.

I wish you luck, and feel free to ask questions before mucking anything up.