850 Piston Rings

I'm rebuilding my '74 Commando engine and have been looking around for piston rings. The pistons and bores in the barrels look good and I plan on measuring everything to make sure all is as it should be, but at this point I assume I can just go with a new set of standard size rings. I plan on using cast iron rings and was wondering what recommendations for brands and sources forum members might have. There appears to be a lot of variability in prices. I'm inclined to go with the higher priced stuff from Old Britts or Domiracer, but suspect the less expensive rings from Taiwan may be as good. I searched the forum's past posts on this topic and didn't find anything specific. Any suggestions you have on what rings to buy and where to get them will be appreciated.

Thanks,

Jim

Jim Malm said:

I'm rebuilding my '74 Commando engine and have been looking around for piston rings. The pistons and bores in the barrels look good and I plan on measuring everything to make sure all is as it should be, but at this point I assume I can just go with a new set of standard size rings. I plan on using cast iron rings and was wondering what recommendations for brands and sources forum members might have. There appears to be a lot of variability in prices. I'm inclined to go with the higher priced stuff from Old Britts or Domiracer, but suspect the less expensive rings from Taiwan may be as good. I searched the forum's past posts on this topic and didn't find anything specific. Any suggestions you have on what rings to buy and where to get them will be appreciated.

Thanks,

Jim

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Well, judging from the last comments on DomiRacer... you may want to stick with Old Britts.

The Taiwanise pistons are good but the rings are not so go for Hepolites, Hastings or Total seal rings. If the pistons are original then go for hepolite as the pistons are hepolite.

Be sure to check the end gaps of the new rings in each bore before final assembly. I just installed new GPM rings in my 850 and found that one set of rings had .003 more end gap in the same bore than the other set of rings. DON"T assume that every set of rings of any particular size actually match. I ended up mixing the rings from the two sets to end up with suitable gaps. This worked with the GPM rings because the 1st two rings are identical; it wont work with ring sets that use, say, a chrome top ring and a cast iron second ring.

Also, there is now a lot of piston ring manufacturer info indicating that the standard practice of narrower gap in the 2nd ring than that of the top ring is wrong and that the second ring should have a wider gap than the top. I know it sounds weird - and different - but it has become quite widespread and apparently improves sealing efficiency by eliminating top ring flutter. I'm not making a recommendation but it's worth doing some research and forming your own view. Here's an example, expand the page so you can read and look at the end gap recommendation: http://www.who-sells-it.com/cy/je-pisto ... ge-11.html