400 CM Build

[bwalker]

I like your idea of decreasing how loud the saw is.
Another idea I had to accomplish this is to make a sandwhich of the front cover and sheet of perf plate with fiberglass insulation between the two. Held in place by some thread studs welded to the front cover.

The perf plate I am talking about.

 

[Duane(Pa)]

I have a different model saw with a pipe outlet on a cat muffler. I really don’t think there is a catalyst, but rather a perf plate. I can see the plate glowing bright red through the piped outlet. Only mention bc I think you will toast any packing in short order.

 

[EFSM]

The perf plate I am talking about.
View attachment 481911

Robin/makita and I think Redmax used to do something similar on their trimmer mufflers. Most of the inside of the muffler was covered in insulation with something that looked like expanded metal holding it on. I don’t know how much it proved, but every little bit helps.

 

[bwalker]

I have a different model saw with a pipe outlet on a cat muffler. I really don’t think there is a catalyst, but rather a perf plate. I can see the plate glowing bright red through the piped outlet. Only mention bc I think you will toast any packing in short order.

That perf plate is coated with catalyst.

The fiberglass packing made for the purpose won't burn. Its used in motor cycle exhausts.

 

[drf256]

I like your idea of decreasing how loud the saw is.
Another idea I had to accomplish this is to make a sandwhich of the front cover and sheet of perf plate with fiberglass insulation between the two. Held in place by some thread studs welded to the front cover.

Hmm. Like an old glass pack muffler. Interesting

 

[Duane(Pa)]

Nothing louder IIRC

 

[bwalker]

Hmm. Like an old glass pack muffler. Interesting

Exactly, with the exception of the flow hitting the cover in a perpendicular manner vs parallel for a glass pack.
I think a set up like this would absorb a fair bit of noise.

 

[drf256]

Here it is. Chain needed work, for sure. I’m pretty happy with it. I believe it’s hickory wood. The muffler pretty quiet for the amount of opening.

 

[cuinrearview]

What's that white *s-word?

 

[David Young]

Wow that thing is strong Doc. What were the stock numbers? 40 from the band?

 

[drf256]

Wow that thing is strong Doc. What were the stock numbers? 40 from the band?

30 from band.

 

[lehman live edge slab]

I stand corrected. I only see a Stihl brand marking cast on the jug. It does have the typical Mahle patina though.

Mahle are much easier to cut vs KS jugs. KS are a harder alloy and more commonly have plating that’s harder and extends into the ports, at least in my limited experience.

Here’s another wax mark. Must be some type of sign on the assembly line.
View attachment 478915

Stihl casts and plates over 90% of their own cylinders in Brazil nowadays. The other 10 or so is the other 3 main makers like gilerdoni, ks and mahle. I suppose they cast as many as they can themselves and let the overflow or smaller runs get outsourced.

 

[lehman live edge slab]

Here it is. Chain needed work, for sure. I’m pretty happy with it. I believe it’s hickory wood. The muffler pretty quiet for the amount of opening.

Cuts well