woodworkingboy
TreeHouser
I thought Al would be a good person to ask about this, but since piston/cylinder damage is something that a lot of chainsaw users encounter, figured that it might be useful to start a thread on the subject.
I have a Husky 359 that I modded extensively four or five years ago, and it has been my main felling saw for smaller to mid sized trees. It suddenly lost compression last week, and thinking that the sealant that I replaced the cylinder gasket with probably blew out, I pulled it apart. It turned out to be a more serious problem. It appears that one of the piston retaining clips broke apart where the curl at the end is, then it must have fallen into the crank case and then was shot up through an upper transfer, where a ring hooked it or the piston edge. It chipped off a small edge from the piston crown, which I think is repairable with some careful welding and filing the ring groove. I have successfully tig welded on a piston before. The ring broke but stayed in it's groove. It is a pop up piston so there isn't a lot of width between the groove and edge of the piston crown. I would prefer to use the piston if repairable, given the work that has gone into it. The main concern is that the retaining clip piece appears to have been dragged up the side of the cylinder wall, so that there is about a 1/32" wide groove in the wall from the top of the transfer to the edge of the flat area around the edge of the combustion chamber. The small broken clip piece was imbedded in the top of the cylinder, and it pried out. There is no other damage, pretty lucky, I think. It would probably run reasonably decent still, but will loose compression down the groove, bypassing the ring. I'd like to be able to patch it, it is a narrow slot.
I have heard of people using some adhesive filler type material to reshape a cylinder wall, but have no experience doing it myself, and don't know what might work. It has to be a very hostile environment for a filler on a cylinder wall. I figure that if I can find something that might work, I can over fill the slot and then sand it down flat. Any suggestion what might possibly work to patch a scar on the inside of a cylinder?
Thanks for any thoughts.
I have a Husky 359 that I modded extensively four or five years ago, and it has been my main felling saw for smaller to mid sized trees. It suddenly lost compression last week, and thinking that the sealant that I replaced the cylinder gasket with probably blew out, I pulled it apart. It turned out to be a more serious problem. It appears that one of the piston retaining clips broke apart where the curl at the end is, then it must have fallen into the crank case and then was shot up through an upper transfer, where a ring hooked it or the piston edge. It chipped off a small edge from the piston crown, which I think is repairable with some careful welding and filing the ring groove. I have successfully tig welded on a piston before. The ring broke but stayed in it's groove. It is a pop up piston so there isn't a lot of width between the groove and edge of the piston crown. I would prefer to use the piston if repairable, given the work that has gone into it. The main concern is that the retaining clip piece appears to have been dragged up the side of the cylinder wall, so that there is about a 1/32" wide groove in the wall from the top of the transfer to the edge of the flat area around the edge of the combustion chamber. The small broken clip piece was imbedded in the top of the cylinder, and it pried out. There is no other damage, pretty lucky, I think. It would probably run reasonably decent still, but will loose compression down the groove, bypassing the ring. I'd like to be able to patch it, it is a narrow slot.
I have heard of people using some adhesive filler type material to reshape a cylinder wall, but have no experience doing it myself, and don't know what might work. It has to be a very hostile environment for a filler on a cylinder wall. I figure that if I can find something that might work, I can over fill the slot and then sand it down flat. Any suggestion what might possibly work to patch a scar on the inside of a cylinder?
Thanks for any thoughts.