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Post by tompriebe on Jun 14, 2023 0:59:58 GMT
A friend of mine asked me for some help identifying some piston rings. Part number is 420 9158.36. I don't have any idea what diameter these are at all so no guesses as to bore size. Does anyone know where I can look these up? Thanks, Tom
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Post by greenandgold on Jun 15, 2023 1:25:10 GMT
It’s a 1st O/S 59.75mm for a type 354. 1981 parts book lists the 420915836 for the Bliz 7500. 1st O/S ring listed in the 1979 parts book for Bliz 7500 is 420915831. Noticed something similar going on with other rotax pistons; don’t know if the number increase was due to supplier change, materials or something else….
BTW, how I track these down is to first look at a known number, I used a 74 type 396. Its ring number was a few hundred less, so I jumped to 78 and looked at “newer” engines, type 444 and 345. Numbers got closer, but not yet over. Next engine that came to mind was a 354, that had the -831 number. Then jumped to a 503 which had a ring number greater than -840. So checked the 1981 type 354 and bingo. Nice that Ski Doo used increasing numbers as they introduced new engines.
I’ve never found a direct parts number lookup. The ol' flip thru parts books routine it is.
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Post by Doo640ER on Jun 19, 2023 11:24:21 GMT
Excellent detective work G&G! I always wonder if you stopped by the nearest Doo dealership, would they still show the part number in the computer system database they use? Or are all old numbers archived?
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Post by tompriebe on Jun 20, 2023 11:25:47 GMT
Thanks for the information! I'll check on the material to see what they are made of. I have seen the number shift, like an "01" to a "06" based upon iron rings vs. chrome rings or something like that. When I find out, I'll let you know.
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Post by tompriebe on Jun 20, 2023 11:35:33 GMT
Looking like the 831 is iron rings, and the 836 is moly coated. Thanks again!
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