need your opinion on piston and cylinder wall, if i need to replace them

[DOJO]

Bought a used stihl 026 and taking it apart to clean and see what needs to be fixed.

Yesterday was able to take the piston out as I wanted to see if i need to change it. When to a local dealer and he looked at the piston thou exhaust and said it's ok. But i still wanted to take the piston out to see everything in close details.

Would like to know your opinion if I need to change it or not as I do not know.


Thanks.

 

[skid row]

I would replace it, its toast.

 

[blsnelling]

Clean the aluminum off the cylinder with acid. Then hone or wet sand with 320 grit. Get a new piston and you should be good to go.

 

[PB]

Clean the aluminum off the cylinder with acid. Then hone or wet sand with 320 grit. Get a new piston and you should be good to go.

I think that piston can be cleaned up, still has the machine marks. Just get new rings.

 

[DOJO]

PlantBiologist, cleaned up with what? sorry, i'm new to this.

blsnelling, do not have acid and don't want to play with it. So was planing on going to a auto part store to get some card cleaning.
Thought this is better then sand paper
http://www.baileysonline.com/itemdetail.asp?item=240AO%2045

 

[skid row]

PlantBiologist, cleaned up with what? sorry, i'm new to this.

blsnelling, do not have acid and don't want to play with it. So was planing on going to a auto part store to get some card cleaning.
Thought this is better then sand paper
http://www.baileysonline.com/itemdetail.asp?item=240AO%2045

New piston and rings. Clean up the piston material from the cylinder walls.

 

[PB]

PlantBiologist, cleaned up with what? sorry, i'm new to this.

blsnelling, do not have acid and don't want to play with it. So was planing on going to a auto part store to get some card cleaning.
Thought this is better then sand paper
http://www.baileysonline.com/itemdetail.asp?item=240AO%2045

You can try a very fine sand paper or some steel wool. For the cylinder I think muriatic acid is what you would use. I have never used it personally, so i can't advise on technique.

For the piston, you just need to get rid of the rough spots, but don't go crazy and take off a lot of material. Make sure that the ring groove is clean.

 

[skid row]

I think that piston can be cleaned up, still has the machine marks. Just get new rings.

Second pic has some bad piston scoring.

 

[PB]

Did you check compression before you took it apart? It looks like it would have fine compression, barely even a scratch on the rings.

 

[PB]

Second pic has some bad piston scoring.

It's not deep and only really on the bottom of the skirt. You can still see the machine marks through the scoring above the ring. The ring looks like it moves freely.

 

[timberwolf]

Depends what you want to get out of it, Quite likely you could just smooth things out and get it running, might last a good while.

On the other hand it's not likely to be a strong saw with parts that rough. Would not be surprised if it was hard starting and inconsistant at low speed.

 

[blsnelling]

Yes, you could clean the piston and rings up and use them. However, if you want to do a proper job, I'd replace the piston and rings. You can get aftermarket pretty cheap and they'll be fine. Maybe not OEM standards, but they'll serve you well.

 

[blsnelling]

PlantBiologist, cleaned up with what? sorry, i'm new to this.

blsnelling, do not have acid and don't want to play with it. So was planing on going to a auto part store to get some card cleaning.
Thought this is better then sand paper
http://www.baileysonline.com/itemdetail.asp?item=240AO%2045

240 grit is too coarse. You want to use their finer grit which I think is 320. That is a plated cylinder wall.

 

[DOJO]

I want to have a good running saw. Took everything the saw apart as it had some oil fouled and don't want to do a half az job. If i have to replace them then I will do it.

It had a bad fuel hose when I bought it made a quick fix and it starts with first pull.

 

[blsnelling]

I don't see anything in the cylinder that won't clean up fine.

Use a Q-tip with Muratic acid to remove any aluminum transfered from the piston. Be careful not to get it on any other bare aluminum. The cylinder is NiSi coated so it will remove the aluminum transfered from the piston and leave a clean cylinder wall.

Then either buy a 320-grit hone, or use 320 wet/dry sandpaper and sand the cylinder. Idealy, you don't want to be able to catch a fingernail on any scratches.

Pitch the old piston and rings if you want to do it right. If you've got the dough, get a Stihl OEM piston and rings. Otherwise get an aftermarket one. I've used the one from Baileys. Meteor is also a highly reguarded aftermarket piston. I'm not sure where to get them.

Order a base gasket and you're good to go. Be sure to tune it properly when you're done with good 50:1 mix.

 

[skid row]

I want to have a good running saw. Took everything the saw apart as it had some oil fouled and don't want to do a half az job. If i have to replace them then I will do it.

It had a bad fuel hose when I bought it made a quick fix and it starts with first pull.

There are hours of great rebuild threads on the 026. Alot of AS members repair saws for a living and a hobby. Do a search and you will learn tons of info.

It helped me out a great deal on all my saw repairs/mods.

GOOD LUCK.

 

[timberwolf]

Worth while also to check out everything else if your going to redo it right, make sure intake boot is good, no air leaks there or on the main seals. Might be due for a carb kit also, likely junk from the bad fuel line has made it's way into the carb...

Be a shame to put new parts into it to have the same thing happen all over again. Might have just been a bad fuel line that caused the problem from the start, but you don't know that for sure.

 

[teacherman]

Look in the Trading Post for a good deal on OEM piston/rings for the 026. Less than 25.00, no reason to go with aftermarket. AS member bcorradi has them still, I believe.

 

[DOJO]

Thank you every one for your help.

Will be replacing the piston and hope after sanding cylinder it will be ok. Spoke to bcorradi about some other parts and he said that he sold everything.

 

[4492011]

AMICKS SUPERSTORE has meteor pistons he is a sponsor on this site and he is a great guy to deal with.