Motorcycle Ring Usage

[hardingfv32-1]

Just moving this subject to its own thread.

Additional information to consider:

Childs&Albert Pistons and Rings are out of business. This leaves us with Pacific Rings, small firm in S CA, as our only source of dykes rings (retailed through Vee sources).

M/C rings are made by Nippon Piston Ring( a couple of US retail/wholesale sources). They are used on a 4 stroke Yamaha dirt bike engine, 10:1 compression and 13k redline. Retail is usually about $30 per cylinder.

The M/C oil ring is 1.5mm going into a 4mm groove. A spacer is require to make up the difference. A little too big for a one piece steel space that would need to snap into place. Steel is just to stiff at this thickness. A aluminum spacer needs to be two pieces to install properly and is held in place with a retaining ring. Hand machined spacers were aggressively market for the Runoffs at about $400 a set. A post Runoffs price for hand machined spacers would be $200. These are of coarse a one time purchase and completely reusable. A CNC piece would greatly reduce the cost.

The M/C ring package has about 40-50% less drag than a current Nat level ring package.

Because the rings are so narrow there is less heat transfer out of the pistons. The ramifications of this are unknown at this time. This could negate the reduced wear form the lower tension/drag. I have not seen anything unusual in the 4-5 years I have run this combination. Wear seems about the same as a normal ring combination.

Brian

[problemchild]

I would suggest that people ask their engine builder about this topic and the 1200/1300 pistons that Mike talked about in the other thread. These would seem to be separate issues but Mike seemed to be connecting the two. I asked two engine builders about these 1200/1300 pistons that Mike was using and both were unaware that they were available or legal.

[brian]

There is an aftermarket piston and cylinder set from China that has a ring land similar to the 1300. They are not 1300 pistons. Appears to be an example of the outstanding quality control out of China.

[sharplikestump]

Really did not intend to combine the M/C ring issue with the Chinese piston issue. My point is that if we choose to or have to go with those pistons, we can cover fitting the M/C rings with ease, saving a substantial amount of $. To my way of thinking, C&A going under just enforces the need for us to have open minds, but no big deal to me. ...You want us to spend more, we'll spend more.
What I don't get is what the gripe is on groove width anyhow, when we have been using spacers for 40 plus years. Narrower groove, you just use a narrower spacer. Fact is, the way I see it, if you want to come up with pistons made that have grooves custom cut to fit the rings, eliminating the spacers entirely, I could give a rat's arse.

[brian]

I agree with Mike. As I said before, based on the costs as I understood them, it could be cheaper with new pistons. If the cost of spacers is less, then it's a no brainer.

[hardingfv32-1]

The M/C oil ring spacers are no more than $200 per set. You would still need 8 C&A spacers for the top and 2nd rings. Obviously this could be a limiting factor going forward with C&A out of business.

Brian