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Author Topic: Fitting new rings  (Read 586 times)

Offline Tony Smith

  • Mt. Olympus Resident
  • ****
  • Posts: 2285
  • Graduate, Wallace and Gromit School of Engineering
Fitting new rings
« on: June 04, 2019, 02:59:46 AM »
Someone asked me a few days ago about fitting new rings to pistons, I cannot remember if it was here or the Facebook page, so I will put my answer in both places.

Firstly if you have Gotze rings (Federal Mogul) then each ring is helpfully etched witht he word "top" so you know which way up they go without having to decode the diagrams.

Secondly, the oil ring will only fit in one place, which means you can only mess up the position of two rings. Hint, the middle ring has the cut-out in its section  whereas the top ring has a chamfer on its upper surface.

The rings for all Nikasil bores are "soft" cast iron, they do not have much tension and they are reasonably flexible - but they will break if you get aggressive with them.

The only tool required to fit them to a piston is your fingers. go gently and flex them only just enough to get them onto the piston and all will be well.

Some of you may own a tool that looks like the top photos below. If you do - please leave it in your toolbox, they make it all together too easy to break rings.

Ring pliers have their place and that place is working on steel rings, not on cast iron ones.

For completeness I've included a photo of the working end as well, and yes that is a 7-rock 860cc piston they are leaning on. I was helping a friend fit and 860cc kit to their bike today. I got to take it for a very quick run when we finished and gently ran it through the gears and briefly up to 110kph, no untoward vibration.

1978 R100RS| 1981 R100RS (JPS) | 1984 R65 | 1992 KLE500 | 2002 R1150GSA |