Some rings will take a bit of abuse before they snap and some won't. I don't know if the quality of the rings has anything to do with it but I wouldn't bet against it.
Please Help Broke New Piston Ring
- Thread starter tim o
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brandonstc6
Addicted to ArboristSite
I'm not sure, I bought a new oem stihl piston for a ms170 and I tried to put in the cylinder using the taper to compress the rings and the top ring broke with no force.
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Right. I'm not sure OEM is always the best in this respect. I've accidentally abused the AM ones and not had them break and I've had them and others break easily. It might be an individual thing. I've worked in mass production and although the product all looks alike sometimes they don't all function the same. Rings are supposed to give a little before they break otherwise they wouldn't work in the engine nor could you compress them.
On that taper, you probably should put some lubricant on the taper if you didn't.
Make sure the ring will fit the locating pin of the piston. Some rings are cut to ride on a certain side. If you miss this step, the ring will not compress far enough to fit in the cylinder. The other thing is cut yourself a one inch wide by six inch long strip of ring compressor from an old two liter pop bottle. Oil it and slide it in. Dont twist the jug.
brandonstc6
Addicted to ArboristSite
I didn't check the rings before I tried it. They were already on the piston from the factory. I suspect either a defective ring or it was on upside down. I've replaced rings many times and haven't had problems and yeah I had to learn not to twist the jug, the hard way on my first rebuild. I did that on an 032 and it broke a ring. I have a set of ring compressors I bought on eBay that I use for the non clamshell saws.
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I got the new ring on the piston, it went on very easily with the wrap method and covered in oil. I was about to try to put the piston back in and got to looking at the cylinder wall again. I have read about the acid removal method, do you guys think it needs it. I dont have the acid but I guess I could find it somewhere. I can barely feel the aluminum when I pass my fingers over, but I can feel it.
know why that doesnt work for me.
http://www.arboristsite.com/community/gallery/photos/4076/
http://www.arboristsite.com/community/gallery/photos/4077/
http://www.arboristsite.com/community/gallery/photos/4076/
http://www.arboristsite.com/community/gallery/photos/4077/
D
Deleted member 135597
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Dude you gotta clean that cylinder upI got the new ring on the piston, it went on very easily with the wrap method and covered in oil. I was about to try to put the piston back in and got to looking at the cylinder wall again. I have read about the acid removal method, do you guys think it needs it. I dont have the acid but I guess I could find it somewhere. I can barely feel the aluminum when I pass my fingers over, but I can feel it.
brandonstc6
Addicted to ArboristSite
I agree! Look into the mastermind method of cleaning up cylinders. Maybe someone here can post a link to the video.
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If you put anything at all in that cylinder as it will seize quickly.
Clean it up or replace
Clean it up or replace
Thanks guys, sometimes I need a kick in the butt. I just tried cleaning the cylinder with sandpaper and scotch brite. I didn't want to go to far, how does it look? Should I go at it longer? I can't feel anything.
http://www.arboristsite.com/community/gallery/photos/4078/
http://www.arboristsite.com/community/gallery/photos/4078/
You can't hurt the nikisil with sandpaper. Get back in there.
Alright, thanks again for the advice guys. I got back in there and sanded till it was all nice and shiny. I cleaned her up real good and lubed the heck out of everything. I must say I felt like a surgeon putting the piston in this time. I never really pushed on anything but the rings and eventually it slipped in (I ended up using the toothbrush method, but all of your advice came in handy). Should be smooth sailing from here. Couldn't have done it without yall.
One more thing, you guys got me wondering if this was something more than bad fuel mix. I looked up the spark plug that was in it. Its not the right one! Part numbers dont even cross. Of course my neighbor says he never changed the plug on it, I think his memory and mind are fading a bit. But if yall hadn't mentioned it, I wouldnt have checked it, and the saw probably would have blown up again and he would have blamed me. Can't thank yall enough.
One more thing, you guys got me wondering if this was something more than bad fuel mix. I looked up the spark plug that was in it. Its not the right one! Part numbers dont even cross. Of course my neighbor says he never changed the plug on it, I think his memory and mind are fading a bit. But if yall hadn't mentioned it, I wouldnt have checked it, and the saw probably would have blown up again and he would have blamed me. Can't thank yall enough.
Actually, you can sand through it.
cstair2000
ArboristSite Lurker
I use a break hone to prepare cylinder before installing piston. Also rinse it out thoroughly and blow it dry.
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RiesePING
ArboristSite Member
Man, this stuff is so confusing to us mortals
I've read on some sites including this one that this is way overkill and others say it's the best way to clean it up. Emory cloth is the best way and now I hear it can eat through the cylinder. I think I'm finally understanding that every process has multiple ways to achieve the end-goal, but common sense and a little critical thinking is the one similarity that is found within all of the processes. That and s#!+loads of trial and error.
You can sand all you want on a chainsaw cylinder, even through the plating and the saw will still run. The problem is the cylinder will not last long. If the cylinder is damaged so bad that you have to hone or sand the cylinder a lot you might as well replace it. Honing is mostly for car engines and other water cooled engines.
brandonstc6
Addicted to ArboristSite
You don't have much to loose by trying a farmertec aftermarket cylinder. They are cheap and you could use the piston and rings you already bought I they are better
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I still go with hydrochloric acid on a q-tip alternated with a rinse, then wet-dry sand paper and dish detergent.
Keep the acid off the port edges and any pits.
Sandpaper is harder than nikasil or chrome so you can do damage with that.
Keep the acid off the port edges and any pits.
Sandpaper is harder than nikasil or chrome so you can do damage with that.
