What Happens if I Mix Rings?

[rs899]

I put a set of Grant oversize rings on a set of Mahle oversize pistons.  For some reason, and I don't think I did it, one of the cast oil control rings cracked.

I have a set of Goetze STANDARD rings.  If I use the oil control ring from this set, will the world come to an end if I file the ends smaller?

In other words, does the curve matter that much to make it worth buying a whole new set of rings?

[JamesT]

Why would you be filing down the ends? If they are standard rings in an overbored block, the gap will be too large already.

The curve does matter a lot. Even a .5mm oversize will put stress on the inner edge of the rings, and would likely cause them to break prematurely. For the cost of a set of rings it is worth it to put the engine together right the first time.

Then again, try it and let us know how it works out for you.

[rs899]

The heat must be getting to me.  I don't mind if it burns a wee bit more oil, but I don't want it to break.  Seems like a fragile ring as it is.

[fatmobile]

I did this once, with the 1.7TD build, those cast oil rings can be very brittle.
 Wasn't sure where I'd find 80mm oil rings without having to buy a whole set.

 Total seal fixed me up with a set of oil rings.
They aren't the one-piece cast rings, they are the 3-piece.
 So you have to be more careful when installing in the cylinders the thin outer rings can pop out between the ring compressor and the block.
 Otherwise they were only around $20 for a set of 4 oil rings.

[rs899]

These pistons were used (from Billybobf via theman53) and they already had those type of oil control rings on them.  When I took them off they looked to be seriously compromised for some reason.  All of them had impressions of the center spacer worn into the two thin outer rings.  They looked like they would break soon.  I would have just reused one of those but I was afraid they would fail.

[R.O.R-2.0]

These pistons were used (from Billybobf via theman53) and they already had those type of oil control rings on them.  When I took them off they looked to be seriously compromised for some reason.  All of them had impressions of the center spacer worn into the two thin outer rings.  They looked like they would break soon.  I would have just reused one of those but I was afraid they would fail.

the 3 piece rings are MUCH TOUGHER than the 1 piece oil rings..