Need some help with a 260 rebuild

[1savagehunter]

Hope someone will be able to help me with a question or two.
#1) I aquired a late model 260 that I will be rebuilding with a new piston/jug. Is there any other option other than a standard 260 jug/piston. My issue is the current jug is a 44.7 mm and I only can find 44mm jugs as an after market kit.

#2) Is there any preferred aftermarket kits ... meteor vs. NWP

#3) This is my first official build so please excuse my basic questions.

 

[sawinredneck]

1) not unless you go with a factory jug.
2)meteor and Golf seem to make the best kits
3) the only stupid question is the one that doesn't get asked.

 

[woodworkingboy]

Changing out a p and c is cool, good luck with the project. Oil the p and c when slipping in the piston for the first time. Make sure the rings are in the groove properly, and if the piston doesn't want to slip in easily once the rings are past the opening, something isn't kosher, so stop. A ring can get moved past the positioning pin sometimes.

 

[1savagehunter]

Thanks guys ... I was hoping there was a larger jug that could get fitted on but guess not. I will most likely throw a Meteor jug and piston on it and see how it goes. I picked up this saw for free from a local dealer and was hoping to try my hand at a rebuild.

 

[woodworkingboy]

Let us know how it goes.

 

[Magnus]

Why the change?
If there is damage you see result of it on piston and cylinder. Changing this does not always mean they are repaired.
I had a few that scored due to seal leak in crankcase.
A couple more with leaky grommet and hoses.
Do it right and change it all if you do anything.

 

[1savagehunter]

That is my plan ... I've been in the industry for many years now but have always had a saw mechanic to do my work for me but have recently become interested in doing more of my own work. I told to saw mechanic to let me know when he ever gets a saw that needs a told end. He even took it all apart so I needed to go through it all. I plan to 1) Clean the entire saw. 2) switch out the hoses 3) do a carb. job 4)install a new piston and pot 5) pressure test the system.

 

[woodworkingboy]

It seems like a great learning experience. I have never wrenched a 260, (I have the older version), but it probably is a good one to cut your teeth on.

 

[CurSedVoyce]

I think Willie did one a while back.....

 

[CurSedVoyce]

Yup......
MS 260 Port Job

 

[Al Smith]

An 026/Ms 260 wouldn't be any different than any other Stihl except it's smaller .Just a top end job is pretty easy to do .Think clean and tidy and you'll do just fine .

 

[1savagehunter]

Has anyone ever rebuilt a 260?

 

[woodworkingboy]

The closest I've come is an 028.

 

[Al Smith]

Like I said the model makes no difference at all .They're all basically made the same .Just remember you're working on a small precision made engine not a 1937 John -Deere model D so kind of go gentle like .

 

[1savagehunter]

Does anyone know what type of power loss I will have going with the 44mm piston/cylinder vs. 44.7 mm original? Does anyone know if any other type top end would fit???

 

[Al Smith]

.7 of a MM wouldn't produce a reduced amount of power to even be noticaable .Besides a lot of times after market P and C kits are ported for increased compression ratios than OEM .

Now I've never as yet needed to use an after market cylinder but I have used Metior pistons and from what I see they seem to do okay .

 

[1savagehunter]

Al how bad of cylinder can you fix up with muriatic acid? I would be interested in trying but the piston melted/brike on one side and scratched the cylinder wall up?

 

[Al Smith]

I have no idea but try it and see .What not to do is get overly aggresive with a flap wheel.Those who claim Nicosil is hard as carbide have obviously only read that some place because a flap wheel will eat right through it .That I can assure you .

You might try easy off oven cleaner with a 3M green abrasive but wear rubber gloves and use good ventilation because it will fume you otherwise .Apply a little let it work a bit ,take the scrubby to it then rinse it off with water .Keep it up and sooner or later all the tramp aluminum goes away .If the nicosil didn't go with it you're good to go .

If the cylinder just has superficial flaws ,tiny ones I wouldn't get real concerned about it .If they are around the circumference of the cylinder though you might be wasting your time salvaging the cylinder .

 

[Al Smith]

More on this .Sometimes a decent donor no matter what the saw is can be snatched from a dead pile at a dealer,found on flea bay or Craigs list .You just have to keep an eye out .Sooner or later a cheapie with salvagable parts will show up .

 

[1savagehunter]

Thanks Al - I will give the cylinder a try. I got this 260 for free so thus far I'm not out anything. Stupid question but what does a straight gassed piston look like ??? is it what I described. This saw is in extremely good shape minus the top half.

 

[Al Smith]

A lean run will peel the aluminum from the exhaust side of the piston .One that has choked to death from dust ingestion will be scuffed on the intake side but not usually burnt up .A snagged ring will usualy grenade itself and come out in pieces and probabley never run again although an exception in the form of an 038 Mag is still alive and well in my shed having survived the ordeal .

 

[CurSedVoyce]

Looks sumtin like this... This was the 044 I did a top end on semi recent.

 

[Magnus]

Straight gas will make piston expand very fast.
Usually you get scoring 3/4 of piston around, or all way around.

Acid help remove alu from cylinder, but if has scores in the lining it is shot.

 

[1savagehunter]

Ok I have never used my macro before but here is my first shots of the piston and cylinder. Suggestions and opinions are greatly encouraged at this point.

 

[1savagehunter]

One more picture