Lakeside53's --361 muffler mod w/photos

[CUCV]

Well I took some time and tried to draw my 372 exhaust port trace in 3D. Basically I wrapped the trace around a cylinder in CAD then took a cross-section of the extruded curves tangent to the cylinder. As expected it did decrease my estimated exhaust port area from 0.54 in^2 to 0.51 in^2.

So over the weekend I made my DP muffler for my 372 by adding a 0.4 in dia. hole.

I also modeled up my stock 288 and 357 exhaust ports in CAD.
I came up with .405 in^2 for the 357 and .607 in^2 for the 288.

Do these numbers agree with what anyone else has come up with?

 

[timberwolf]

Here are a couple of photos of an 026 muffler I did up today, a bit different, a bit more area, but cuts well.

 

[CUCV]

Does anyone know where to get a sheet of spark arrestor screen, or what saw has a larger than normal screen to be use on a DP mod?

 

[Lakeside53]

044 and 066 is pretty big. I have couple, of sheets but can't remember where I got them.

 

[Freakingstang]

The best way to do this is make your outlet the size you need, and arrange the screen so it's several times the area of the actual opening. This is what Stihl does on their pro saws and to some degree on all saws/OPE - and if you do, you can pretty much just forget its effects both initially and over time. It's not just the new screen occlusion that matter - the wires get coated with fuel additive debris (that tan stuff - not just "soot") and get significantly thicker.

I showed one way of doing this on on the 361 muffler mod thread.

I was referring to the screen pixel size, not the whole screen piece (ex 1"x2"). The diameter of the wires in the screen play a huge role in air flow.

I agree though, the screen should be bigger than the hole by a considerable amount.

 

[scottr]

Wire cloth

CUCV , www.mcmaster.com has wire cloth in sheets .

 

[musch]

Here are a couple of photos of an 026 muffler I did up today, a bit different, a bit more area, but cuts well.

VERY NICE!!!
Does the location of the pipes heat up wood, or are you cutting mostly smaller stuff?
I recently modded my 346xp similarly.
Pics will come soon.

 

[artie__bc]

Thanks Andy for the part # for the dual port muffler cover. I bought one and it works fine.:biggrinbounce2:

 

[timberwolf]

Musch, it only spends 1.5 seconds in a cut, just not enough time to heat the log up.

I am working more towards racing than using it in the bush, there is no screen, though it would be easy to add one on the inside. Saw is boarder line as far as a woods saw anyway, compression is high and it is pretty much like trying to start an 066 without the decomp.

 

[ASEMASTER]

you have made me sick

it's 51 deg. outside the day before our whitetail deer rifle season and I need to put fire wood inside. BUT where am I? In my shop doing another muffler mod. on my cs340 now this thing has some bark with its bite . yeha am i going to cut some wood now.
I can't wait for the husky to get broke in so I can do it to it .:biggrinbounce2: :hmm3grin2orange:

 

[Gumneck]

CUCV , www.mcmaster.com has wire cloth in sheets .

Scott

You are a resourceful guy. I was just in Lowes looking for a rubber well nut for my Poulan 3300. Unfortunately your link didn't have 5/8ths diam by 1" long.

 

[scottr]

3300

Tom , what is a rubber well nut ?

 

[Gumneck]

Tom , what is a rubber well nut ?

Here ya go. Its the one on the right. The rubber piece on the left is part of the vib dampening holding one side of the handle to the flywheel side of saw. The first one lasted 10 years or more. But I've replaced two in the last two years.

So I thought these things are just dry rotted on parts shelves by the time I got them. Decided to see if I can rig something up better. The wellnuts will work but I'll have to drill the caseing out a little to accomodate a bigger screw.

I've thought about using the two broken pieces with a longer screw and just putting the nut behind the rubber plug part(having drilled the plug part out for the screw to go thru).

 

[scottr]

Barry mount

Tom , that looks like a Barry mount . I wonder if you could make one with a threaded pipe and some silicone rubber .

 

[CUCV]

CUCV , www.mcmaster.com has wire cloth in sheets .

Scott, Thanks for the tip! I was about to buy a strainer at Kitchen's etc.

 

[Engineeringnerd]

My 372XP and 346XP muffler mods

All this talk of muffler mods made me anxious, so I decided to break out the Dremel and BBQ paint on my 372XP and 346XP. I just mounted a 32" bar on the 372 and wanted to help it out with this mod before tackling a big oak in a few days. I also want to run a 20" bar a little faster with the 346. The 346 has worked reasonably well in the past with 20", but could do better.

I opted for the "thru-bracket" approach. The 372XP turned out the cleanest as far as fabrication goes. The hole is a rectangle with radius corners approximately 1" 1/16" wide x 9/16" High. I started by drilling two 1/2" holes next to each other, then ground out the rest with the Dremel. I went slightly larger since I was using a tight screen. Had to grind of the carb needle limiters to richen things up a bit. The 372 seems to run good, but I've only made a few cuts thus far.

The 346XP mod was a little more difficult as I had to bend out a flange around the new muffler port to mate with the back side of the muffler bracket. The factory muffler has a gap between the muffler and the bracket, and I needed it to mate together in order to hold the screen in place. I cut a rectangle with radius corners 7/16" Wide x 9/16" High, once again using tight screening. Not as pretty a job as I would have like as it started to rain on the wet paint and caused it to blister. Runs really well though. The 346XP had plenty of carb adjustment, so didn't have to modify the needle limiters. It really seems to have livened up, but I haven't cut wood yet due to rain.

After all this Dremel work, I may become a dentist!

 

[Freakingstang]

All this talk of muffler mods made me anxious, so I decided to break out the Dremel and BBQ paint on my 372XP and 346XP. I just mounted a 32" bar on the 372 and wanted to help it out with this mod before tackling a big oak in a few days. I also want to run a 20" bar a little faster with the 346. The 346 has worked reasonably well in the past with 20", but could do better.

I opted for the "thru-bracket" approach. The 372XP turned out the cleanest as far as fabrication goes. The hole is a rectangle with radius corners approximately 1" 1/16" wide x 9/16" High. I started by drilling two 1/2" holes next to each other, then ground out the rest with the Dremel. I went slightly larger since I was using a tight screen. Had to grind of the carb needle limiters to richen things up a bit. The 372 seems to run good, but I've only made a few cuts thus far.

The 346XP mod was a little more difficult as I had to bend out a flange around the new muffler port to mate with the back side of the muffler bracket. The factory muffler has a gap between the muffler and the bracket, and I needed it to mate together in order to hold the screen in place. I cut a rectangle with radius corners 7/16" Wide x 9/16" High, once again using tight screening. Not as pretty a job as I would have like as it started to rain on the wet paint and caused it to blister. Runs really well though. The 346XP had plenty of carb adjustment, so didn't have to modify the needle limiters. It really seams to have livened up, but I haven't cut wood yet due to rain.

After all this Dremel work, I may give up cutting wood and become a dentist!

Mods both look good, but you wouldn't need a 32" bar if you took those dawgs off. Too much dawg for east coast wood on that saw. Retarded huge, they are!

You could probably get the same cutting surface with a 24" bar and the stock east coast spikes!!!!

 

[Engineeringnerd]

Yeah

I must agree the dawgs are a bit bigger than I expected when I ordered them. They are 1" longer than stock. Sure do grab the wood though!

Nothing about this saw makes sense for me anyway, pure weekend joy.

 

[Rspike]

All this talk of muffler mods made me anxious, so I decided to break out the Dremel and BBQ paint on my 372XP and 346XP. I just mounted a 32" bar on the 372 and wanted to help it out with this mod before tackling a big oak in a few days. I also want to run a 20" bar a little faster with the 346. The 346 has worked reasonably well in the past with 20", but could do better.

I opted for the "thru-bracket" approach. The 372XP turned out the cleanest as far as fabrication goes. The hole is a rectangle with radius corners approximately 1" 1/16" wide x 9/16" High. I started by drilling two 1/2" holes next to each other, then ground out the rest with the Dremel. I went slightly larger since I was using a tight screen. Had to grind of the carb needle limiters to richen things up a bit. The 372 seems to run good, but I've only made a few cuts thus far.

The 346XP mod was a little more difficult as I had to bend out a flange around the new muffler port to mate with the back side of the muffler bracket. The factory muffler has a gap between the muffler and the bracket, and I needed it to mate together in order to hold the screen in place. I cut a rectangle with radius corners 7/16" Wide x 9/16" High, once again using tight screening. Not as pretty a job as I would have like as it started to rain on the wet paint and caused it to blister. Runs really well though. The 346XP had plenty of carb adjustment, so didn't have to modify the needle limiters. It really seems to have livened up, but I haven't cut wood yet due to rain.

After all this Dremel work, I may become a dentist!

Holy smaker ! Lets see a few side shot pic's of the 372XP with them monster 5 point dogs on her.

 

[Engineeringnerd]

372XP with big feet (side pix)

Here goes!