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Piston rings
Posted: Mon Jan 26, 2015 7:02 pm
by swifty
Hi . When I purchased my mk1 S project a few years ago the original engine came with it in kit form . It was rebored , crank ground , new bearings , pistons etc . Has anyone come across a oil scraper ring on the bottom of the piston such as this . All of the other piston oil scraper ring I've fitted have had a top and bottom ring and the wire bit in the middle . These seam to be ... H.. in shape with no top and bottom ring . Are they ok or have I inherited a cheap set of pistons ? The only markings on the inside of the piston is C726 and PT . . Ken
Re: Piston rings
Posted: Mon Jan 26, 2015 7:27 pm
by rich@minispares.com
They look like 21253 and those rings are just the more modern 'easy fit' rings,
I tend to fit the main ring, then 'worm' the inner bit in, once its fitted I just chase it round so its ends are 180 deg away from the ends of the main ring. Its a lot easier to fit than the old three part sort (or was for a amateur like me!)
Re: Piston rings
Posted: Mon Jan 26, 2015 8:00 pm
by ianh1968
Courtesy of our "Hog" friends...
When I built my 74x86, I used one of these...
http://www.dragbike.com/dbnews/template ... 0&zoneid=5
Direct from V&H in the good 'ol USofA, and delivered in no time at all.
I've never had much luck with those "shim-and-jubilee-clip" type tools
and it beats using 3 screwdrivers and a nylon hammer, especially for
anyone that only has two hands!
I am sure that the 73.4mm version would be usable for 73.5mm if it had
a very slight "tickle" with a needle file... It might not even need that.
Bet you never thought of using Harley Davidson tools on a Mini?
Ian
Re: Piston rings
Posted: Mon Jan 26, 2015 9:50 pm
by Spider
I have used those rings (and the pistons) and I gotta say, the rings, in particular, the oil control rings are aweful things. Every other Piston / engine manufacturer is going to thinner rings, but on no, not these ones.......what were they thinking.
The ones I was supplied came in an AE Box, with take a metric ring and so I'm prtty sure you're locked in to replacing them only with AE Rings, though they do have the traditional 3 piece oil rings sets that will fit those pistons. If you replace them do so as a set, do not just replace the Oil Control Rings. And throw those god aweful things in the bin, but break them first so the next guy isn't temped to use them on something.
Re: Piston rings
Posted: Tue Jan 27, 2015 1:55 pm
by swifty
From what I can gather these are Nippon rings . Minispeed are advertising the pistons as being better than powermax . Spider what do you think is the downside of using them ? . I will be using them in a standard 1275 S engine .... Ken
Re: Piston rings
Posted: Tue Jan 27, 2015 2:07 pm
by rich@minispares.com
swifty wrote:From what I can gather these are Nippon rings . Minispeed are advertising the pistons as being better than powermax . Spider what do you think is the downside of using them ? . I will be using them in a standard 1275 S engine .... Ken
they look like the GOETZE brand rings that are supplied with the NURAL/AE pistons
they have the AE mark on them, so they must be ae ring (one would hope), if the rings are supplied on their own, or in the newer pistons they have 'GOE' on them instead
if the ring is .1181 thick its a 21253 high comp piston
if the ring is .1575 thick its a 21251 low comp piston
Re: Piston rings
Posted: Tue Jan 27, 2015 6:44 pm
by swifty
Thanks for that . Well according to your measurements rich I have 21253 . I think il run with them ... Ken