i've got a 93 ta with only 25k miles on it, i've had the car since it was a year old(so i know the mileage is correct). i don't understand why the rings would be bad or what i could of done to cause it. but my #3 plug has burnt crusted oil on it everytime i pull it out. i/we thought it was a valve seal problem, so replaced all the valve seals, yet the problem still exists - which leads me to believe the rings are bad on #3.

what are my options for fixing it? and what will it cost me?

the car seems to run fine, and i'm not getting noticeable smoke.

thx for your help!

 

Well, from the pics on your website, I notice you have nitrous... Think that might be at least part of the cause?

Nice car though...

Greg

 

you could blame n2o except that i haven't even run a full bottle through it yet, not to mention the fact that it was happening prior to the nitrous.

just in case the next question is, why did you put n2o on the car if you knew there was a problem? well i didnt really think there was a problem.. i just assumed that it was the valve seals(the car does sit ALOT which dries out the valve seals) and that it was fine after i changed them - especially since the rings should not be bad in a car with that few miles and is not abused. in fact i hadn't pulled the plugs in a while, as i said it runs fine. i pulled them not too long ago, and sure enough #3 was messed up. so i put a new one in and have been checking it after i drive it, and it always has a bit of oil, kinda burnt looking on it. the others plugs are perfect.

 

Did you try a compression and leakdown test on it? That may confirm your suspicions about the piston ring(s).

Greg

 

no, not yet, i'm planning to, i have to get a gauge. not sure exactly how to do it, since i've never done it before. do i have to have all the plugs out, or just all of them on the side your testing?

 

I'm not 100% sure on the procedure for a 4-stroke - I'm really a 2-stroke person (haha, don't say a word!).

A leakdown gauge is a much better means of diagnosing a problem like that than a compression gauge. Since a 4-stroke engine doesn't have exhaust or boost ports like a 2-stroke, I would venture to guess that it shouldn't matter if the plugs are all in or all out - as long as the piston is at TDC on the compression stroke (of course).

Greg

 

A compression test should be done this way, but you can probably get an indication without pulling all the plugs. It takes a special apparatus to do a leakdown test as well. If you suspected problems, these should have been the first things you should have done.

 

i'll buy some gauges and do a compression and leakdown check, but seems like it will be hard to pull the plugs and do the test with the engine hot.

assuming i find that i have a ring issue, what are my options as for fixing it?

 

Shoebox,

What is an acceptable leakdown on the LT1? I know for my boat race motors we accept 2-3% as good.

Also, we test compression with the throttle butterfly(s) wide open (engine warm too).

93TA, if you're sure it's a ring issue, you'll have to pull the engine and take it apart for further inspection of the piston and cylinder walls. The leakdown test will give you the best indication of the condition of your rings by measuring how well they are sealing.

Here's a photo of our leakdown tester in action. It connects to an air compressor to pressurize the cylinder. Make sure you're not in neutral while testing.

We secure the flywheel while testing...

Greg