Alpin944

Old post, I know. But I'm having trouble getting my old pistons with newly fitted 2 piece piston rings into the cylinder. Seems like they are wider than the old 3 piece ring, and therefore can't be compressed enough. Can anyone please help me?

Charlie

Put the rings into the cylinder without the piston and measure the end gap. Check to see what the end gap specs are.

Voith

If ring gaps are not properly set, your engine can self destruct.

http://www.hotrod.com/how-to/engine/1818/

http://www.wiseco.com/PDFs/Manuals/RingEndGap.pdf

Or do you mean ring itself doesnt fit in the piston because ring is thicker?

Alpin944

Exactly Voith! I can get the ring into the piston, but not alle the way, missing about ½ mm. With the pistons tight fit into the cylinder, it'll newer get in there. I've read that the rings from the 951 (2 piece) now is used for the 944, and the original 944 rings (3 piece) is discontinued. Any thoughts on that?

Charlie

Take a ruler and put the ring 2 inches down into the cylinder. Check all the way around the ring to make sure it is 2 inches in all places. Then take a feeler gauge and see what the gap is. If the gap is within spec then you are OK with the ring.

Also make sure there is not a ridge at the top of the cylinder. If there is take some scotch brite and clean it up.

The ring compressor has to compress the ring almost completely inside the piston groove. If the ring end gap is OK then you may not be compressing the rings enough. Put some oil inside the compressor to make things slide easier.

Voith

Ive never seen 3 piece oil ring in original pistons.

michaelmount123

Your problem is your piston oil groove is not machined for the 2 piece Goetze type oil ring, and it won't accommodate the radius of the spring against the flat inside wall of the groove. This condition won't let the ring go deep enough in the groove as you report.

Solutions: Either get the correct 3 piece oil rings, or send your pistons to http://www.rebco-machine.com. They will remachine the groove so the rings fit. They are very inexpensive and quick. Imagine that.