ms260 muffler issue, piston/cyl damage?

[hamish]

your cylinder is completely salvageable. Take a little time with form fine grit emery cloth and lots of lube, throw in a $30 piston and rings and you are good to go............after you change out that leaking seal of course.
Your saw in your current state dependant upon use and frequency of use can still provide alot of service, a little tlc and your laughing with a runner for the next many years. Two-strokes can take alot of abuse, before they eventually die. Almost weekly I am amazed at the shop, with saws that still run, and run good (even warm) with scored piston and cylinders.

 

[RAMROD48]

Pull the everything off the clutch side of the crankshaft....how's the end seal and bearing?

Seems like I am seeing a bunch of clutch side bearring failure's on 026's

 

[PogoInTheWoods]

your cylinder is completely salvageable.

Those pits are more than the typical dimples and irregularities from initial manufacturing and certainly appear to be deeper than the plating. I wouldn't waste my time trying to clean it up for that reason alone. And if you get acid into those pits? Forget it. But that's my opinion.

Good luck.

Poge

 

[stderr]

Pull the everything off the clutch side of the crankshaft....how's the end seal and bearing?

Seems like I am seeing a bunch of clutch side bearring failure's on 026's

The clutch side seal is not leaking, and both bearings are silky smooth, or they must be, as the crankshaft turns freely and quietly, with virtually no play.

Are you suggesting the cylinder pitting has something to do with the bearings? Also, when you say 026, do you mean 260s as well? This one's a fairly new model, with the 44.7mm piston.

Speaking of which, I measured the piston w. a caliper and it came out to 44.5mm. How close to 44.7 should it be?

 

[stderr]

dumb question

I think I already know the answer to this, but I'll ask just to be sure.

When ordering the piston, should I order gaskets for this as well, or can the gaskets be reused? I'd never reuse a gasket on a car engine, but nobody ever says get a muffler gasket and crankcase gasket too. Maybe it's just assumed you would never reuse them? I notice they aren't included in a p/c kit or a piston kit.

 

[RAMROD48]

I think I already know the answer to this, but I'll ask just to be sure.

When ordering the piston, should I order gaskets for this as well, or can the gaskets be reused? I'd never reuse a gasket on a car engine, but nobody ever says get a muffler gasket and crankcase gasket too. Maybe it's just assumed you would never reuse them? I notice they aren't included in a p/c kit or a piston kit.

Yup, get new gaskets base gasket for sure...you might get away with the muffler gasket, but if your going to the expense of doing the rebuild, whats a couple more dollars....

 

[stderr]

After a little dusting and cleaning...

Tried the muriatic acid treatment. I have nothing to lose at this point, so why not? Here's the results:

The intake side looks OK so far. Not so good with the exhaust side...

Those pits aren't getting any smaller, and certainly are more obvious now that most of the mess is gone.

I'm not sure how to interpret it, but that right-most pit looks like it's got small cracks around it.

 

[RAMROD48]

I have nothing to lose at this point

:agree2:

nope....go get a P&C and be done with it....

 

[PogoInTheWoods]

Tried the muriatic acid treatment.

Good that you at least gave it a shot from the aspect of experience, but no way was that cylinder salvageable with those type of pits.

Contact Brad Corradi (bcorradi) for p/c and gasket kit options. He'll fix you up quickly at a very reasonable price.

Good luck.

Poge

 

[stderr]

oil seal, carb limiter cap(s)

While waiting for the P&C to show, I tried prying out the leaking flywheel side oil seal today. I don't have the right tool, so perused a few threads here explaining different tactics for getting the little devil out. After several hours, and several attempts at fabricating a tool, I think it's time I took it into a dealer and had them pop out the old seal. Unless there's somebody in this neck of the woods who has one (Vancouver BC area). This is proving a very frustrating experience, and I'm afraid I'm going to end up gouging the crankshaft if I keep at it.

I tried using a screw driver, a dental pic, a formed piece of heavy gauge coat-hanger, and a link of bicycle chain formed into a nice sharp hook using a dremel tool. I tried gently tapping the metal part of the seal with a screwdriver to see if it at least would move inward. It does move in, but it's sure not coming out by my hands.

Moving on, part of the plan was to open up the muffler, so I ordered a used muffler off ebay to play with. The one I have here doesn't look like any of the mufflers I've seen on the site. I thought it would be smart to experiment with a used one, and if I make a mess I still have the stock unit. Still waiting.

Moving on some more, I removed the carburetor, and noticed it's a Walbro with a limiter cap only on the H screw:

I tried the drywall screw trick to pull the cap out, but as I tightened the screw, I noticed the H screw was turning in. Not wanting to have it turn right in and damage the carb, I stopped and tried to pull with the screw only part way in. I ended up breaking the cap (some days you're the windshield, some days you're the bug).

Do I need to salvage or replace the limiter cap in order to run the saw, or can I just toss it and tune the carb as needed?

 

[oscar4883]

The cap should be replaced. But if you get the saw back together before you get the cap I would run it without it to get it tuned. Before real world use though, I would get a new cap on it. My dealer had to order every limiter cap I have ordered. Hopefully yours has them in stock. I think it would be very hard to mess up the crank getting seals out. Boogering up the case may be a different story though. Volks-man did a very nice thread on using the Lisle seal puller to get cranks seals out of, I think, an 026. I'll post the link if I can find it.

 

[oscar4883]

http://www.arboristsite.com/showthread.php?t=117673&highlight="lisle+seal+puller"

 

[andrethegiant70]

This is sort of embarrassing, but I've run cylinders that look like that. The one in my ported 026 does not look too dissimilar. The saw starts and runs well and I have no real complaints. I think if I didn't port it, though, I might not be as happy. Yours could use some more clean-up, and those pits are pretty weird, but they won't funnel air to any of the ports. I can tell you that the saw will run, it just won't be a compression hog.

If you really want a really good runner, replace the jug. If you are on a tight budget, you should feel free to give it a try. Maybe try your hand at porting. If you don't want the jug, I'll buy it off you. PM me if you'd like.

 

[stderr]

P&C arrived

oscar4883, well that's a bummer. For now I've just stuffed the cracked cap back into the hole. I trimmed the little tab off so I can turn it. I'll ask about a new one. If anybody has a parts bin lying around, please let me know if you have one.

andrethegiant70, stop rubbing salt in my wounds . I think for now I'll hang on to the cyl. If I blow up the new one, I can go back to it.

Speaking of the new one, it arrived today, very nice. I thought when he (bcorradi) said it was OEM he was just sorta sayin' that (no offence intended, just been my experience on flea-bay). He wasn't. I was pleasently surprised.

There are two studs on top of the old cyl that didn't come with the new one. I used a small propane torch to warm up the bosses on the cyl. head, then unscrewed them with a vice-grip. They look like they might have had loctite on them or something. I looked in the service manual, didn't see anything about intsalling this piece. Can anyone comment on whether it's needed?

On the off-chance I can get the crank-seal out, what's the preferred sealant for around the outside of the seal? The Stihl service manual is a little vague on this. They mention what section to look in, but don't list a sealant of any kind, at least not that I could decipher.

Thought I'd give pulling the flywheel side seal one more shot. Broke the bicycle chainlink I had fashioned into a hook in half. I think the seal is more stubborn than me.

 

[super3]

Drive the seal down just a little first. It will come out a lot easier.

 

[stderr]

oil seal

Already tried driving it in a bit. It moved, but it didn't make it any easier to get the seal out.

I called the local Stihl dealer, and after being quoted $80/hr to look at it, with no guarantee of success removing the old seal, and no warranty on the new seal if it isn't supplied by them, I thought I should not give up just yet.

I took an old trade-show freebee screwdriver, and tried bending the tip 90°. The steel's too hard. I heated it up w. a torch and it bent much easier. I'm sure I took the temper out of it, so I guessed at heating it back up, then quenching it cold water. This allowed me to hook the edge of the seal much much better. Then the handle ripped off of the screwdriver shaft. I warmed up the other end of the shaft and bent the last inch or so to 90°. I didn't bother to try to retemper it. I then used a pry-bar under the 1" part of the shaft and lifted. This time, it moved, just a little. I then worked around the seal one bit at a time, and finally, mercifully, it came out. The shaft and the seal mating surface on the crankshaft look pretty clean.

I'll add pic's later.

OK, it's later:

What should I use as a sealing material around the outside part of the new seal? Nothing? Grease? RTV Red?

When mounting the Cylinder, should there be any sealant on the gasket, or do I just bolt it on?

Lastly, there was no leak on the clutch-side, but I have the extra seal. Should I? Or should I not fix what ain't broke?

 

[PogoInTheWoods]

Already tried driving it in a bit. It moved, but it didn't make it any easier to get the seal out.

I called the local Stihl dealer, and after being quoted $80/hr to look at it, with no guarantee of success removing the old seal, and no warranty on the new seal if it isn't supplied by them, I thought I should not give up just yet.

I took an old trade-show freebee screwdriver, and tried bending the tip 90°. The steel's too hard. I heated it up w. a torch and it bent much easier. I'm sure I took the temper out of it, so I guessed at heating it back up, then quenching it cold water. This allowed me to hook the edge of the seal much much better. Then the handle ripped off of the screwdriver shaft. I warmed up the other end of the shaft and bent the last inch or so to 90°. I didn't bother to try to retemper it. I then used a pry-bar under the 1" part of the shaft and lifted. This time, it moved, just a little. I then worked around the seal one bit at a time, and finally, mercifully, it came out. The shaft and the seal mating surface on the crankshaft look pretty clean.

I'll add pic's later.

What should I use as a sealing material around the outside part of the new seal? Nothing? Grease? RTV Red?

When mounting the Cylinder, should there be any sealant on the gasket, or do I just bolt it on?

Lastly, there was no leak on the clutch-side, but I have the extra seal. Should I? Or should I not fix what ain't broke?

Don't mess with the clutch side if it tested good. No reason to.

No sealing material required for the new seal. Just be real careful putting it into the case so as not to skew it. Should only be slightly deeper than the top of the casting.

Different schools of thought on the cylinder gasket sealant. I didn't use any
and haven't had a problem as a result. But there ARE two gasket sizes. You
more than likely have the correct one if you bought your kit from Brad.

May want to take a look at this thread if you haven't already -- and never go back to your local Stihl guy ever again for anything if he wants 80 bux an hour just to "look" at your situation.

http://www.arboristsite.com/showthread.php?t=122800

Good luck with it. Sounds like you have a handle. You're asking all the right questions.

But no pics? Didn't happen.

Poge

 

[stderr]

shaft, case pic's

Here's the shaft and the case around it. Man, a good close up with a camera sure makes this look scary. To the naked eye it looks just great, but those scratches, yikes:

 

[oscar4883]

The two studs need to on the new cylinder. The flywheel side stud holds the top cover on and the one on the clutch side gets a rubber bump stop lookin thing. When you get the seals installed and top end on make sure to pressure and vac test it to check your work. Rotate the crank a few times when vac testing in particuliar.

 

[stderr]

cylinder studs

Thanks Oscar, the studs are installed. I was more curious about whether they needed loctite or not. It looked like there was a little loctite remains on them when they came out of the old jug, but it was hard to tell. I didn't add more, but I did warm up the new cylinder a bit and thread them in with a vise-grip.

P&C mounted too. This went fairly smoothly. The zip-tie as ring-compressor worked like a charm. A little dumb to ask now, but what should I have used to lubricate the cylinder? I used a little 30wt motor oil.

Poge mentioned getting gaskets & seals from Brad. I had already ordered a fleabay kit before talking to him. Not sure what you mean by different gaskets. I know there's a 1mm thick one and a 0.5mm thick one. The one I got is 0.5mm. I read somewhere that one is for high-comp, the other low-comp. Not sure why you'd want anything other than high-comp.

Still mulling over the issue of sealant on the outside of the crank seal. Any other opinions?