Piston rings
- Thread starter pierodn
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What was the bad experience? I have just replaced my GPM rings with Hepolite. The GPM one piece oil rings developed 2.1mm gap on one bore and 1.1mm on the other, after 15k miles. The bores were not worn very badly and the compression ring gaps were acceptable at 0.42 and 0.55mm.
Ok, I understand. I also did this but it was my own fault, installing pistons without a ring compressor. However, that was a one piece GPM sourced part. The 3 pc are very flexible so I suppose it is possible to trap the narrow ring in the bore and shear it in two?
B+Bogus
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I wonder if there are more than one type of Hastings ring out there...
The Steadfast supplied ones are 3-piece
http://www.steadfastcycles.com/cart/ind ... ts_id=4435
One potential pitfall is that the expander needs checking for gap as well as the rings themselves - I've had to trim them in the past... after I found it difficult getting the barrels past the oil rings :wink:
The Steadfast supplied ones are 3-piece
http://www.steadfastcycles.com/cart/ind ... ts_id=4435
One potential pitfall is that the expander needs checking for gap as well as the rings themselves - I've had to trim them in the past... after I found it difficult getting the barrels past the oil rings :wink:
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Absolute fucking bullshit.
There is nothing wrong with using those 3 or 4 pc oil rings. You just have to KNOW what you are doing when fitting them.
You don't gap the expander. NUTs.
generally you will find there is good clearance on the wipers. There is no problem having a so called wider gap with these rings. I do always check their gaps anyway to make they have some. [ more than the one pcs ones ]
Wanker
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That is what my infamous Ms Peel ran with in her prime til over over rev event distorted-destroyed everthing *outside* of engine cases,then was transfered to Trixie Combat by use of Peel's cylinder and pistons after factory tabbo oil slotted ones came apart while about coasting at 50 and worked fine till a reused rod bolt broke while about coasting 50's sightseeing again. I don't claim any performance help detected just such nil blow by no matter the rpms a Q-tip swab in clear breather hose off TS case had no hint of oil mist which I understand is IMPOSSIBLE as comnoz and followers says so > if no flapper valve mounted right on cases and TS volume not blocked off but for lowered oil level holes - so must just be my misleading everyone again. Keeny Dreer was my breather mentor back then and we know what happened to his way of making Commandos better.
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B+Bogus said:
No. Listen mate, you can do anything you like, but don't expect the manufacturer to guarantee anything YOU modify, and don't recommend that practise to anyone else. If it doesn't fit, you have the wrong part. [ and wrong parts do get packed occasionally but it takes a good mechanic to recognise the difference ]. Its not the same as reaming bushes to suit. Nor is it like the magnetic drain plug I just purchased for my g/box. The threads hadn't been turned up to the head of the "bolt" so I made a thick spacer to take up the slack, rather than turn the threads up further and modify the new part.
Dereck
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I seem to recall a post maybe a year or two ago where a fellow was lamenting about oil literally puking out of the exhaust after a re-ring job. Yep, he trimmed the expander on the three piece oil control ring. :shock:
The silver lining in his cloud was that trimming the expander made offering the pistons and rings to the barrel so much easier. :roll:
For most applications, as stated so eloquently by others above, don't trim the expander.
The silver lining in his cloud was that trimming the expander made offering the pistons and rings to the barrel so much easier. :roll:
For most applications, as stated so eloquently by others above, don't trim the expander.
B+Bogus
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For the sake of clarity, this isn't new to me - I've fitted many 3-piece rings in over 30 years and I wholeheartedly agree that they should never need to be messed with in any way.
But what do you do when the piston simply won't fit in the bore otherwise?
It may be a quality escape, but I didn't dive into this without checking my facts first - you've either encountered this issue, or you haven't!
Evidently I'm not the only one either.
Furthermore my bikes don't smoke.
But what do you do when the piston simply won't fit in the bore otherwise?
It may be a quality escape, but I didn't dive into this without checking my facts first - you've either encountered this issue, or you haven't!
Evidently I'm not the only one either.
Furthermore my bikes don't smoke.
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The last re ring I had to do on my std bore 850 was with hepolite 3 piece ring, this was back in 83 or 84 and despite my shortening on the rings the bike still runs well with out blue smoke or excessive oil consumption in 2014. They were just not going to go in without a trim, same type rings did not need trimming on an Audi Diesel done a few years later.
Beach
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B+Bogus said:
Same here.....This is the first time I had ever encountered this after many rebuilds....I checked with several rebuilders to make sure what to do first...Concensus was without trimming the expander, the piston would not fit....After several thousand miles my bike does not smoke...I also think main reason for the expander is to keep the scraper rings separated....
....And to apply the pressure against the walls needed to seal the bores whilst at the same time any oil that finds it's way between the rails to drain to the inside of the piston. I suppose there could be instances where an oil control expander was packaged wrong, say a part meant for an over size bore finding it's way into a standard set, that would be real obvious though and go back to the vender. Are the guys who are trimming these things using ring compressors or just fingernails to work the rings in?Beach said:
Beach
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Ring compressors...When you tighten the ring compressor as far as it will go and the oil rings will still not slide into the cylinder, there is something wrong..I think several people have had this problem with the Hasting ring sets...Return the part? Maybe, but there is still a chance to get same thing...After trimming the expander rings one square and reinstalling there was still enough tension to press against the scrapers....I was hesitant at first doing this , but after talking to several people who do rebuilds on cars, they assured me it would work fine...I guess just like myself, you never think about this happening, until it happens to you..I would not hesitate doing the same thing again..
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