Case damage on MS260

[Binthewoods]

MS260 got smashed and one of the muffler bolt mounts broke off the case, what are my options for repairing this?

I assume a case half would be best but could I just weld a nut on the back of a muffler and mount the muffler to the cylinder and 1 spot on the case and the bad side just bolting the muffler and muffler cover together?

 

[Stihl99]

That is magnesium just FYI. If it was me I would just replace the saw with a 261, but if you prefer the carb model them I would purchase the new half case to make it right and not half-ass it.

 

[Vintage Engine Repairs]

Two options - the ideal solution-

Replace the cases - I’d use a donor saw rather than buying new. It’s an excellent model saw and so many were sold that parts for them are like mushrooms - they are everywhere.

Alternatively, the more cost efficient and quicker solution - that bolt doesn’t do much, it just holds the front cover down.

Ahough it acts as a second support area for the muffler, there is no force that gets applied to it. Without that bolt, there are still 3 other firm points of contact , two at the cylinder, one at the bottom left of the front cover.

Ensure that the other bolt is nicely secured with Loctite and at the same with them two at the cylinder and then take a small bolt and two washers you could simply bolt that cover against itself. You may need to file away some of that damaged area to make space for the nut.

In years to come, if there is an issue with the other bolt hole, then replace the cases then. Even then - many old saws had 1 piece mufflers with only 2 sometimes 3 bolts. Generally 2 into the cylinder and 1 onto the case. Or just two onto the cylinder alone.

 

[pioneerguy600]

Its only a light tin muffler, it will do fine with just 3 Stihl serrated under head screws/ T27, holding it in place. I woulkd check the tightness occasionally but have never seen the screws back out if tightened correctly from the outset.

 

[Woodslasher]

Option #3, you could see if @srcarr52 can weld it up and re-drill/tap the hole.

 

[sawfan123]

3 screws with red loctite. You'll be fine. I've seen 660's with only 3.
Just be sure the saw isn't over speeding.

 

[Binthewoods]

Thanks guys, I'll get it back together as-is and keep a close eye on it.

 

[Vintage Engine Repairs]

I’d still suggest the nut and bolt on the 4th hole. You may very well get vibration embrittlement and end up with a cracked muffler. Don’t ask how I know

 

[Binthewoods]

I might try welding a nut to the back of that muffler hole to be able to bolt on the outer muffler cover.