The piston rings on my Ruston Hornsby 6PS are well and truly stuck in the piston can anyone advise on the best way to get them out. The piston has sit in diesel for about 6 weeks now and hasn't made any difference. Also where could I get a set of new rings from should they break?
after wiping the diesel off first!!) up to a few hundred degrees might help loosen them up , then back in the diesel when it cools down to about 100 degrees( we dont want any nasty fires strarting do we) Somebody else will be able to tell you upper and lower critical temperatures better than me. Steve the grease
I don't feel that well qualified to talk about stuck rings in view of my recent experience with the Norman T300! But those were little skinny ones in aluminium pistons. I have found with the earlier wider types in cast iron pistons, that repeated soaking + heat + lots of tapping with light hammer and soft drift usually produces evidence of a little movement after a while.
BTW. I remember quenching red hot iron in oil in school metal working classes, it only caught light if you took it out again too quickly!
Heat and swift cooling, time, penetrating oil (I prefer Plus Gas myself) and occasional gentle worrying at the ring ends with a small screwdriver to see if they are free yet will always do it in the end.
Not too hot or you will de-temper the rings and a floppy ring is no good to anyone ;o))
The heating and swift cooling cycle is the heart of it and the flame should be principally applied to the piston crown, that part of the piston expected to deal with it.
Swift cooling cycles will eventually crack the rust, corrosion and hard carbon, Plus Gas etc only speeds it along
Hi Liam, You'll need a can of spray penetrant, a hammer, and a brass drift. If drift is stricty an American term, it's the tool that looks like a center punch but is flat rather than pointed.
Hose the piston down with the penetrant, then using the hammer and drift, tap on a ring, starting at one end, with moderate force. Don't go crazy, just tap for a little bit, then rotate the piston a little. Continue this tapping procedure all the way around the circumference. Keep going around and around.
It may take several revolutions before you notice any movement on the ring. Eventually you'll see the ring start to be pushed downward into the groove. Don't push it too far, just rotate the piston and move on.
Eventually all the tapping will allow the penetrant to get in between the ring and the lands and free up any carbon or rust.
Again, don't go wild. The rings will be springy, but if you get too enthusastic you'll break 'em.
=-=-=-=-=-=-=-=-= Rob Skinner La Habra, California
I have just tried heating it up and allowed it to cool a bit in the diesel and started gentaly tapping the rings. One of them has started to move, but will have to keep trying to get the other 2 moving. I would prefer to get new rings I have asked
and they quote £5 for the compression rings and £6 for the oil ring, does this sound the right sort of price? I will call Thorntons of Shrewsbury (01743
357081) next to see what they have.