2nd Compression Ring - Chamfer Up or Down?

[TheLoneRanger]

Rebuilding a Kohler K321 and got a .020" oversized Piston & Rings from Lil Red Barn. The piston rings did not come with any instructions nor are there any on their website, which is odd to me.

The top ring has no markings or chamfer which tells me that it can be installed either way. My question is about the 2nd ring, it has a chamfer.



Which way does it go?


Thanks, Ranger

[Ambush]

Last winter, I bought a .010” piston from lil Red Barn for a K321. And like you, no info on which way the chamfer went. And I was little surprised there wasn’t a chamfer on the outside of the top ring. I did a ton of googling and convinced myself I did it correctly, but unfortunately I don’t remember which way I put it, sorry. But I recall that most of the pro builders had the same advice.

I was also disappointed that the wrist pin wall was very thick causing even more imbalance. I did weight the crank.

[ol'George]

First ring, bevel goes up
Second ring bevel goes down.
Unless manufacturer specify otherwise.

[TheLoneRanger]

Originally Posted by ol'George

First ring, bevel goes up
Second ring bevel goes down.
Unless manufacturer specify otherwise.

Thanks! I did some Googling last night and came up with the same answer.

[Billy-O]

I photoed this page out of the Kohler single cylinder Engine Servive Manual.... Kohler shows that the chamfer facing up on top ring and also the second facing up. I guess they were showing different variations of rings that could be included in the set of rings as this is a little confusing. Sorry for the rotated picture

20250928_191922.jpg

[TheLoneRanger]

Originally Posted by Billy-O

I photoed this page out of the Kohler single cylinder Engine Servive Manual.... Kohler shows that the chamfer facing up on top ring and also the second facing up. I guess they were showing different variations of rings that could be included in the set of rings as this is a little confusing. Sorry for the rotated picture

Found a pdf of the manual you got the picture from here. Didn't see this manual in the Technical Library.

It's interesting that Kohler says to install the 2nd ring with the chamfer up. Every where I've looked says to do the opposite. Being that this an aftermarket Piston & Rings and not OEM Kohler, I'm inclined to put the chamfer facing down.

[Grandpa53]

It depends on whether you're talking about inside or outside chamfer. Be sure you're reading ALL of the instructions.

[ol'George]

Over the 65 or so years I've been twisting wrenches, I've seen it both ways.
But generally install them as I mentioned UNLESS the directions state otherwise.
In your situation we have to assume either way will work ( oh boy THAT word)
since no instructions are provided.
Also if you didn't bore/hone the bore you can expect it to use oil either way, depending on your taper and out of round, I do hope you did a light DEGLAZING so they would have a chance to conform somewhat to the irregularities and break the glaze on the walls.

Do not "break it in" with synthetic oil, use good old dino oil giving it at least some chance of bedding the rings to the cylinder wall.
I hope the crankshaft is true and the piston to wall is the proper clearance,
if not you will still have the "noise" you heard.
And after a few heat cycles, retorque the head, as you will be amazed how loose they have become.
I hope I have not offended you if you are knowledgeable of these things, as we have no way of knowing your experience.