Scored pistons-What % ruin the cylinder?

[Gwiz]

Seems like from what I read here, a lot of scored piston cylinders can be saved. My mechanic said 'most' can be saved when I asked him. My first one, a Husky 261, has a deep grove in the cylinder and appears wasted.
I thought I was playing with the odds in my favor, but now I'm a 1 for 1 loser. What are the odds of the cylinder being wasted?
Can you generally tell by just looking at the piston with the muffler off?
James

 

[huskydave]

50/50 sometimes you can tell but it all depends where the grooves are and how deep they run. You can save the ones with grooves below the exhaust port and use muriatic acid to clean up galling and aluminum deposits. I turn over the flywheel slowly and listen to the compression as it builds when I pick up a parts saw. I can tell a lot from this technique and if I hear it leaking at top dead center and the flywheel turns very freely and the piston has deep grooves then the cyl is usually toast but sometimes you get lucky and the cylinder can be saved. I have noticed the saws that build compression stop then resume are in better condition than badly scored cylinders. For what I pay for nonrunners about 30 bucks it makes little difference to me. The dealers would have the most accurate percentage of cylinders that can be saved this is my personal limited experience only.

 

[Ray Bennett]

I am a looser here too. I got a freesaw and tried to salvage the cylinder and use a new piston. Needles to say I failed, Now I will be buying both P/C

 

[Mad Professor]

Score in the piston it might live, scored cylinder get a new one. Unless an old time cast iron bore you can bore out, hone , and fit an oversize piston to.

Others milage may vary but any scored nikasil/chromed cyl. is a POS IMHO.

EDIT: Let me be clear a NEW piston in an undamaged cyl may work. A new/used piston in a POS cyl is asking for trouble..........

 

[Lakeside53]

I save way over half... and I'm real picky...

 

[StihlNut88]

I save about two out of three saws. I use a little muriatic acid on a cotton swap to take off any deposits and then run a hone through it. I use a snap on ball hone myself and they usually come out pretty good. I have had good luck doing it that way.

 

[Gwiz]

50/50 sometimes you can tell but it all depends where the grooves are and how deep they run. You can save the ones with grooves below the exhaust port and use muriatic acid to clean up galling and aluminum deposits. I turn over the flywheel slowly and listen to the compression as it builds when I pick up a parts saw. I can tell a lot from this technique and if I hear it leaking at top dead center and the flywheel turns very freely and the piston has deep grooves then the cyl is usually toast but sometimes you get lucky and the cylinder can be saved. I have noticed the saws that build compression stop then resume are in better condition than badly scored cylinders. For what I pay for nonrunners about 30 bucks it makes little difference to me. The dealers would have the most accurate percentage of cylinders that can be saved this is my personal limited experience only.

Mine is grooved the deepest above the exhaust port. My first clue was when using the muriatic acid. That one line was the only place that just kept bubbling. I'm sure it's the aluminum from behind the cylinder lining. Anyone know the best source for an OEM P&C for a Husky 262xp?
Thanks James

 

[Lakeside53]

Groove though the plating above the exhaust is a problem - compression zone...

 

[StihlNut88]

Mine is grooved the deepest above the exhaust port. My first clue was when using the muriatic acid. That one line was the only place that just kept bubbling. I'm sure it's the aluminum from behind the cylinder lining. Anyone know the best source for an OEM P&C for a Husky 262xp?
Thanks James

I buy all mine on ebay and have had good luck, although I would like to find more sites to buy them, anyone know any good sites?

 

[Nitro-Fish]

I buy all mine on ebay and have had good luck, although I would like to find more sites to buy them, anyone know any good sites?

Check Bailey's Online, they have a lot more than what's listed in their catalog, both OEM and aftermarket. They're great to do business with; one of the site sponsers too.

 

[Gwiz]

Check Bailey's Online, they have a lot more than what's listed in their catalog, both OEM and aftermarket. They're great to do business with; one of the site sponsers too.

I was going to make a separate post, but I'll put it here. Bailey's did me right today. I might not be doing myself any favors by using their aftermarket piston, but I already had it here when I realized my cylinder was bad. I called them to see if the piston in there P&C kit was the same as the one I bought separate. I was assured it was, but they could not sell me just the cylinder. I was going to have to send my piston back and get the same piston back from them in the P&C kit. I was asking why they couldn't just keep the piston from there kit? The guy on the phone left to talk to the warehouse or something and when he came back, he sold me the P&C kit less the price I had already paid for the piston. Now I have an extra piston kit that I didn't even pay for. That's the kind of service that will bring me back.
James

 

[Sethro]

I save way over half... and I'm real picky...

Andy, what is the main cause of scoring in your area ? Carbon deposits dislodging and getting behind a ring.

 

[Lakeside53]

I see... in order...
1) raw gas (homeowners...)...
2) User adjustment of the H screw... hey.. It worked MUCH better when I turned that thing IN...
3) blocked inlet screen in carb... decomposed fuel filter...

There a few more that I just don't know the cause... and a few that are because of users continuing to use a saw with a bad air or fuel hose leak (won't idle, but I can run it at full throttle!). yes, I see a few with jambed rings, broken rings, clogged with carbon.. but..

 

[Gwiz]

I see... in order...
1) raw gas (homeowners...)...
2) User adjustment of the H screw... hey.. It worked MUCH better when I turned that thing IN...
3) blocked inlet screen in carb... decomposed fuel filter...



I'm no mechanic, but all the stories I've heard about raw gas ended in seizure. Then I read here, if a saw is seized don't even try to save it. What do you see on those?
James

 

[Lakeside53]

I save many... new piston, but a good percentage of the OEM cylinders clean up. Crank and bearings are rarely affected.

 

[Bowtie]

It amazes me how the bearings in a 2 stroke engine take the abuse they get WITH correct mix and maintenence, let alone raw gas.