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Post by lesorubcheek on Jun 22, 2009 14:31:28 GMT -5
Suppose someone came across a 2100S... 2-1/4" bore with standard piston rings, not the thin ones used on the Super. Looking at replacement rings, there's a couple of saws with slightly larger bore (58mm) that have aftermarket rings available. Namely, Stihl 070 and 075/076. Pretty sure they're all 1.5mm thick.
Could these rings be trimmed down a bit and used as a replacement for the 2100? I think the Homelite ring will be blunt faced with no recess for the locator pin. Not sure how the Stihl rings for either model looks. Anybody know what the ends of the rings look like on a 070 or a 075/076? Biggest concern is that if they are ground with a recess for an alignment pin, it may not make sense to just try to file them down.
Dan
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Post by cbfarmall on Jun 22, 2009 19:41:11 GMT -5
I just got a brand new set of rings from Hawkins for my 3100, thick rings. Don't know about the thin rings but I'll bet that Mac 101 rings will work. They even had a ring for my 2100 headland piston.
To answer your question, you are in luck as I just happen to have a NOS 2100 thick ring piston and an 076 piston for comparison. The thickness works out and it looks as though you can file the Stihl ring ends square and have plenty left over to set the end gap.
Chris B.
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Post by cbfarmall on Jun 22, 2009 19:52:39 GMT -5
BTW,
I measured the ring thicknesses.
2100: .063
076: .059
I hope this will work out for you.
Chris B.
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Post by lesorubcheek on Jun 22, 2009 20:56:31 GMT -5
Chris, you're awesome! That's great information to know. I knew they should be close, just wasn't sure about the ends on the stihl rings. I also hadn't considered the thickness. Looks pretty close.
Thanks,
Dan
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Post by MCS on Jun 22, 2009 21:40:07 GMT -5
BTW, I measured the ring thicknesses. 2100: .063 076: .059 Chris B. I'd say the 2100 has rings that are 1/16" (.0625') The 076 is metric .059" = 1.5mm Since I don't think you will find metric rings and english with close enough thickness in these small sizes, there is a .0035 difference, that would only leave English to english but... 2 1/16" bore has a circumference of 6.480" 2 1/8" bore has a circumference of 6.676 You would have to grind off quite a bit but would it work? Probably but you would increase the side wall pressure. You can get away with this in car engines. I have a '56 Chrysler hemi that is bored .060 over. 3 15/16 + .060 = 3.9975" .060 over rings are available but I can get 350 chevy rings, 4.0" bore and the same thickness a lot cheaper. |
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Post by lesorubcheek on Jun 23, 2009 7:37:00 GMT -5
Yes A7, the thickness has me a bit concerned too. For some reason I was assuming the thickness wouldn't be an issue. I didn't consider metric and english here. The more I think about it, probably wiser to look at Hastings or another rings supplier and try to get 1/16" rings instead of chancing the 1.5mm ones.
Dan
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Post by billg on Jun 23, 2009 14:46:29 GMT -5
If you need any other measurements I can check some of mine. I have all three versions of the 2100 pistions new. I also have new 070 pistons. I can check and compare them. Bill  |
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Post by billg on Jun 23, 2009 14:52:04 GMT -5
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Post by lesorubcheek on Jun 23, 2009 14:54:21 GMT -5
Yea Bill, I thought about Hastings. Looks like they have a ring with that's the correct thickness.
Dan
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