Piston Ring End Gap Issue (Goetze)

[bw86newman]

During my M20 rebuild, I am having an issue with the end gap with new Goetze standard size piston rings. Top ring gap is about 0.018" and lower ring gap 0.021" right out of the box. Only checked two of the ring sets as if I have to go in a different direction, hopefully I can return the others.

The original rings are similar with top being 0.017" - 0.018" and lower being 0.021"-0.022".

Measurements were taken based on Bentley manual approx. 5/8" below top and then also as far down the bore I could push the rings down with a piston.

The only work done on the block at the machine shop was the top surface being machined flat. Piston, cylinder bores, crank and journals were checked and I was told all were in spec and to get standard size for bearings and rings. Although, I don't have any numbers for this.

I know that the Goetze rings are pre-gapped and will expand and slightly close the gap when hot, but starting cold at the high end of the tolerance worries me.

This is a similar issue to what NJ2.5rser had in this post: https://www.r3vlimited.com/board/sho...ht=piston+ring but not sure what the outcome was.

Any help/insight into this is greatly appreciated.

[Elysian]

If they're in spec they're in spec. I wouldn't worry about it.

[ForcedFirebird]

I set them to .014" top .018" second when file fitting, but you are close enough to run them based on experience. The ring gap isn't as important as gap placement.

Built a 2.7 for a client he has been daily driving for 6mos. He is planning turbo so I opened up the gaps to .018" and .020" during the build (as well as studded and o-ring'd block), and there's no issues.