#3 piston ring stuck
 

I did a refresh on my engine last fall and have put about 2,000 miles on it since. When doing the cylinders I honed them to get a nice cross hatch (there was no ridge), installed new rings, made sure the rings gaps were in spec etc. I did a compression check on my engine yesterday and found
#1 90
#2 87
#3 55
#4 81

I squirted a fa9ir amount of oil into #3 and the compression went up to 90.

BTW, I have a 5.5 Snydedr4's head.

So, the problem is with the rings. I did find the compression ring stuck in the groove on #3 when I redid the engine, but I think that I cleaned the groove so that did not reoccur. Apparently I was wrong.

Short of removing the head, oil pan etc., is there something that I can squirt down the hole to try and loosen the ring? For example would the 50/50 mixture of acetone and ATF have a chance of working?

Any other suggestions?

Dick

Re: #3 piston ring stuck
 

Likely, there is no short fix for the stuck ring. Something is holding that ring locked to the piston. I would drop the pan, remove the head and that piston to locate what is causing the problem. Look for signs of scoring on the #3 piston. A bit of metal could have worked its way between the ring and the piston.
Good Luck!

Re: #3 piston ring stuck
 

Dave's right, some times, and it is very easy to get a ding on the out side of the ring groove, and if you don't catch it, the ring will move but has no clearance and when it heats up, it tightens up.

Herm.

Re: #3 piston ring stuck
 

Thanks Dave and Herm for the advice. Just for the hell of it I squirted some 50/50 solution of ATF and acetone into #3, let it sit for a while, went for a drive and rechecked the compression. Predictably no change other than the smoke killed all of the mosquitoes in the vicinity!!

I will remove the head, drop the pan, remove the piston and fix it properly as you have suggested.

Dick