gbgastowers

Has anyone had any experience with sticking piston rings in an engine that has not run in years? Is there such a thing as rings that are just sticking but are still good? I have a 2nd engine in my 82 Euro S that is only starting when I add some oil to the cylinders through the plug hole. I restored this car and replaced the M28/11 engine with a M28/12 that I resealed and had the heads rebuilt on.Decided not to do the rings. I couldn't get it started for the first time till today when added the oil to the cylinders after Porsche mechanics advice. Now it starts,but only when I add oil to the cylinders and throttling up a little keeps it running till I let off the gas. Then it dies and wont restart. I checked Google and found the Rislone web site advertising a ring seal oil additive that also says it can free sticking rings. http://www.barsproducts.com/rislone_faq.htm

from the site=What are the most common causes of low engine compression?
Low compression can be caused by normal engine wear and decreased sealing between the piston rings and cylinder walls. This can be the result of scratches in the cylinder walls or sticking rings in the pistons which allow compression to move from the top of the cylinder down into the crankcase below the piston.

How does Rislone Compression Repair with Ring Seal work?
Rislone Compression Repair with Ring Seal works two ways to solve low compression problems. First, chemical polymers work to fill in scratches and grooves in cylinder walls caused by normal wear, age and high mileage. Secondly, frees sticking rings in piston grooves to allow the rings to properly seal increasing compression.

This is probably BS witch oil but do sticking rings exist and how do you unstick them?

928 at last

Have you done a compression test to see which might be the problem?

Landseer

Doesn't the engine oil the rings?

Do you have oil pressure when it starts?

928 at last

Generally only from the bottom.......splashes up the cylinders.......
Pressure probably wouldn't help. RPM might.
If there's some compression to be had, we've used a couple of things over the years to free things up, but not on a Porsche engine.

James Bailey

By far the most common cause of very low compression on all cylinders is a badly overheated engine which got so hot it compromised the spring of the rings...... and nothing in a can will fix that. This was the engine which before they shipped it too you they said it had low compression ? Seems they were correct.....

gbgastowers

I did my first one ever a few days ago after Landseer suggested it due to my no start. I checked 3 cylinders with a borrowed(O'reillys) gauge. Questionable results were around 30. I was upset and thought the gauge might be wrong so borrowed another one and got low readings so did a wet one and got 160-240. I might check into a leakdown test or redo the compression test better to see what cylinders are affected.

gbgastowers

The gauge read pegged up when running and when I turn on headlights it pegged down all the way.
Even after rebuilding the cluster it looks like I have gauge problems and gauge illumination probs. Warning lights work.

neilh

Or, at this point, as you are working this and the 'other' BB, and getting similar feedback and advice, accept the engine is shot as Jim suggests, and pull it again and do a ring job. No amount of oil, compression testing and other tbd voodoo will fix your problem right now, and forget about the cluster gauge problems -
Sorry, but you have a re-ring in your future.

Landseer

Would sure be nice to find a confirmed-running 4.7 for a fair price.
Apply your newly reconditioned Euro heads and roll.

gbgastowers

It looked so pretty when I removed the heads(that had never been off) it was hard to believe it had problems. I had the heads to it rebuilt and they found 4 slightly bent exhaust valves that I thought might have been due to some unyielding lifters I found. After a lot of time spent trying to make the right decision the wrong one was made. I am a newbie basically and these forums got me this far and I'm sure they'll see me through. Gunar

928 at last

So there's some history here. James is right. If the vendor said it had low compression, and you had it apart.......
Looks like it's going to be coming out again. If there were just some old carbon or light corrosion, that's a lot different than cooked rings.

gbgastowers

This is a big "fn" step that I am not looking forward to doing and I am simply trying to rule everything else out. I think I have.

namasgt

The cylinder walls look pretty good. I dont think its your rings. We did a compression test on later car and it was showing 30 psi when it was cold, we put some oil in the cylinder from the spark plug hole and it end up showing 160-180 psi. The car is running fine now.
Did you do any media blasting to the intake?

neilh

I think most of us on here that have been following you feel your pain, but you are approaching that point where you have to say 'yes' and get out the engine hoist. Good luck, if i was anywhere near close to you i would be right there to help -

gbgastowers

So now we swing the other way...... I wish you were right. No media blasting done. What happened with your car between putting oil in the plug hole and getting 180 psi and to running fine now?