Thread: Need Help Solving this engine puzzel

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It is not a HOT Rod question but it is an engine question I figure you guys have torn all kinds of engines. Here is the puzzel

This is a 1997 Pontiac 3.1 engine

The engine started running real rough. Note no engine codes, great plugs wires etcetc. I took a compression reading and I found that 1 of the pistons read 30psi and the other 5 read 150psi. Thinking I had burnt valves I took the head off and I found that the valves were perfect. I then poured 6 onces of tranny fluid in the sick piston and 6 ounces of tranny fluid in a good piston in the morning I found that 1/2 of the tranny fluid had leaked into the crank case and in the good piston most of the fluid was still there. So can I asssume that the rings are shot in the sick piston. Yes/NO

squirt oil in the sick pistion, and recheck compression. will verify bad rings. should read 150 wet

Originally Posted by Matt167

squirt oil in the sick pistion, and recheck compression. will verify bad rings. should read 150 wet

I did that before I took the head off and ther was very little change, It may have read 32psi vs 30psi That is why I pulled the head off thinking it was the valves

I have read it may be collapsed rings broken rings etc etc. Also the cylider walls are are perfect.

I'm thinking broken rings.........they just havn't scored the cylinder yet...........lucky you.

Originally Posted by poncho62

I'm thinking broken rings.........they just havn't scored the cylinder yet...........lucky you.

I am thinking the same, I was also told that if the rings were collapsed then soaking the piston in trany fluid "might" release them. I don't know if that makes sense I don't know what a collapesed ring is!

Originally Posted by DennyW

A collapsed ring is when the ring can no longer expand against the cylinder wall to seal it. A broken ring amounts to basically the same thing, cannot seal against the cylinder wall anymore. Tranny fluid might work. A lot of times, this is an over time thing, and the piston lands have become scored, and will capture the ring tightly. So the the metal, or carbon will not allow the rings to free up. It would be worth a try. You could soak it, tap lightly, and see if the rings would free up, but more than likely, you will have to get into it to fix it.

Thank-you for the feed-back a well informed answer. I have spent almost 1-1/2 days getting to the head gasket in this dam 1997 3.1 Grand-Am " give me a gm 350 any day" Now the next big thing is to drop the oil pan, there are over 20 items that need to be removed just to remove the oil pan. I am now at a cross roads Do I sell it for a few hundred dollars or do I spend another 2 or 3 days getting to the oil pan.

Has any one use "Engine restore" with any success. I do know I have a piston ring broken or warn-out

Well I used tire pressure to do the leak test and sure enough I could hear the air come from the crank case at a pretty go rate. It's amazing what one can do by improvising. I wish I had done this before I rip off the head hopping the low 30-psi was a burt valve. The leak test would have saved me 12 hours of work. I guess I learned a lot. Thanks for all your support.

Time to do a proper engine repair.