Help me solve this puzzel

[Rolm]

The 3.1L engine when idiling was real rough not just a miss real rough, when I raised the rpm to 2500 it did smoth out but I could still feel a miss
I checked the following, Perfect Plugs, wires, fuel , No smoke, no back-fire, No oil or anti-freez leaks

The next thing I did was a compression test all pistons read 150lbs and 1-read 30 lbs. I figure great I must have a burnt valve or blown piston. I rip the head off and this is what I found. The piston that had the 30-LBS the exhaust valve was bright white the a-joining exhaust valve was a light brown and the rest of the valves were a light black. The head gasket look good. I did the following to track the leak if any. I turned the head over and filled all the indent in the valves with tranny fluid in the hopes of tracking a leak "NO LEAK" (NOTE no sticky valves) Next I pourded at least six ounces of tranny fluid in the cylinder with the low compression and the same amount of fluid in the good cylinder and in the mornig I noticed that half the fluid was gone in the sick cylinder and in the good cylinder almost all the fluid was still there. The cylider walls were perfect the cylinders were also perfect.

No what. I hate to close thing-up with out fixing any-thing.
Vette-73 is online now Edit/Delete Message

[JustSayGo]

An easier more effective way to check the valve is to clean the oil out of the combustion chamber, set the head on its side and fill the port with solvent. If you see the slightest leak it will cause a miss. Is the cam opening the valves? Look at the valve springs and guess at a comparison of their pressure. Target in on the intake valve. if it is leaking back into the intake it disrupts the other cylinders. One bad cylinder would just be a miss.
No doubt you will eliminate possibilities.

If oil leaked past the rings there must be something seriosly wrong with the rings on the piston in the bad cylinder even though the cylinder looks OK. Push that piston out and take look.

[Rolm]

Originally Posted by JustSayGo

An easier more effective way to check the valve is to clean the oil out of the combustion chamber, set the head on its side and fill the port with solvent. If you see the slightest leak it will cause a miss. Is the cam opening the valves? Look at the valve springs and guess at a comparison of their pressure. Target in on the intake valve. if it is leaking back into the intake it disrupts the other cylinders. One bad cylinder would just be a miss.
No doubt you will eliminate possibilities.

If oil leaked past the rings there must be something seriosly wrong with the rings on the piston in the bad cylinder even though the cylinder looks OK. Push that piston out and take look.

What do you mean push out the piston, How do I do that is it as easy as dropping the oil pan and unbolting the rod and pushing out the piston?

[GTP Dad]

To push out the piston, remove the oil pan, remove the rod cap and push the piston up and out of the cylinder. Make sure there isn't a ridge in the cylinder or you will damage the piston. This sounds like a broken ring on the #1 cylinder. You will need a ring compressor to replace the piston once you replace the rings and if the bearing is bad replace it too. Won't hurt since you are there anyway.

[Rolm]

Originally Posted by GTP Dad

To push out the piston, remove the oil pan, remove the rod cap and push the piston up and out of the cylinder. Make sure there isn't a ridge in the cylinder or you will damage the piston. This sounds like a broken ring on the #1 cylinder. You will need a ring compressor to replace the piston once you replace the rings and if the bearing is bad replace it too. Won't hurt since you are there anyway.

I will do as you suggested, I hope removing the piston will easier then removing the cylinder head what a horrror-story that was. I will keeep you updated. Wish me luck

[Rolm]

After reading the steps required to remove the oil pan on AUTOZONE and the need of a ridge reamer to remove the piston and so on and so on. I decided to button things-up and intall new gaskets and hope for the best. Oh yes I will try the tranny fluid trick, As I did before I poured around 6 onces in the so-called sick piston and in a good piston and see how long it will take to drain past the rings. I don't know if this is a valid test.