piston groove

aaronk785 said

Hi all. I just read an article by weseco pistons on ring grooves. They say you don’t want more than .018 behind the ring because it takes to long for the pressure to build and push out on the ring. The last several sets of rings I have bought have a narrower top ring horizontally. So now I have over around .040+ behind the top ring. They just started doing this awhile back. Just got my short block together and read this. Why would the ring companies do this. And should I worry about it.

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Depends on what you expect. For me, I expect the rings to fit the grooves and not have all that wasted space behind the ring. The real seals by compression pressure dropping dow the face of the piston, hits the top of the ring and then goes across the ring to the groove where it gets behind the ring and forces the ring against the cylinder wall.

Gas ports (horizontal, vertical or gas ported rings) all allow the gas pressure to get behind the ring quick, to get the seal quicker.

Either the pistons are machined incorrectly (very unlikely IMO) or the rings are just cheap pieces that are low performance.

I’m not wired in a way that would allow me to let what you have slide. Many others would run them and never think about it.

You have to decide who you are and then live with it.