361 Shootout

[timberwolf]

Not bad at all stock. But the torque is weak and it would not take much pushing to drop RPM.

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[gink595]

OOO, a TW thread!! cool. Here is the pics. See if I can help here.

Question for ya TW, are you tig welding your mufflers? Last time I did a muffler was the first time with my new tig, and I had a hell of a time cause the filler was too thick, couldn't find any thinner. So I haven't tried it yet but was going to try to use some mig wire as filler since its sooo much smaller. What do you use?

You should be able to weld thin gage with .060 filler, I have some .040 filler, but actually perfer to use .060 on 22 ga. I can turn the amperage up a bit and run a little faster than if I turn it down and use a smaller filler. Same with tungsten, I found it easier to weld with a larger diameter tungsten on light gage than to go with a smaller tungsten. I know it sounds crazy but try it, you can get more heat in faster to start your puddle and then you can go like hell rather than trying to drive the heat in the material and then go slow with the puddle.

 

[Tzed250]

You should be able to weld thin gage with .060 filler, I have some .040 filler, but actually perfer to use .060 on 22 ga. I can turn the amperage up a bit and run a little faster than if I turn it down and use a smaller filler. Same with tungsten, I found it easier to weld with a larger diameter tungsten on light gage than to go with a smaller tungsten. I know it sounds crazy but try it, you can get more heat in faster to start your puddle and then you can go like hell rather than trying to drive the heat in the material and then go slow with the puddle.

Is that how you will do it when you build the pipe for my 660???


.

 

[gink595]

Yes

 

[timberwolf]

Gink, you right about it going faster with the 1/16, I just found I was able to keep the welds smaller and put in less heat with lighter filler, also on the pipes ended up with smooter finnish on insides. I have tried the .040 tungsten, did not like it and went back to 1/16 but grind a fairly fine point. But all that is just learning by doing so no saying if it is right or wrong.

Here are a few pics of doing another muffler from the start.

I find it best to open the crimp on the 3 sides opposite the outlet as they are easiest to close back up. 4 spot welds to grind out then pull the screen and the basket is gone. Restristion is 8.75mm so only about 0.09 square inches.

 

[timberwolf]

Compression was between about 165 or a little more and 175 or a little less on all three saws, have not checked the BB yet but will put it together stock eventually.

All three saws were new and 1 was lean from factory.

 

[RTK]

That lean plug picture sure looks lean, either that or it is brand new

 

[timberwolf]

Plug had been run for a few min then saw shut off right out of full load cut.

Anyway off to look at some differences between the 361 Stihl and BB jugs. Something interesting with the transfers. Stihl jug has transfer ducts that measure about 5.8mm x 19.2mm, BB Jug has ducts 4.1mm x 17.2mm. Works out that big bore has only about 63% of the transfer duct area.

Wonder if that will show up on the dyno and in the wood. Got a feeling that this is going to hurt the top end.

5mm bolt for scale, BB on left, Stihl jug on right.

 

[Trigger-Time]

Compression was between about 165 or a little more and 175 or a little less on all three saws, have not checked the BB yet but will put it together stock eventually.

All three saws were new and 1 was lean from factory.

Seems most 361 have good compression.

I do take it 361 in video muffler was stock not just the motor.

Am really looking forward to you finding out what the best
size of sq in of muffler opening is for stock saw. I'm looking for the
smallest sq in that gets the cherry of the gains.

361 muffler I posted pictures of was on my first 361 the gills
added .140 sq in. I had a little trouble with idle on that saw
but it idles and runs good on the new 361. I kind of think
it was the carb on first. It would seem like I had it, cut with it
set it down and it would die.

TT

 

[Outlaw5.0]

Seems all big bores have small transfers. My first gen 460BB had larger transfers than my 2nd gen 460BB.

 

[timberwolf]

Upper transfers are pretty close, BB has a bit more angle going into the cylinder but size wise very close.

The lowers end up small I think on many BB's because there is not a lot of room to clear the flywheel on that side and case on PTO side, then the bore eats up 1mm extra on each side.

Head volumes came in about 6.1cc to 6.4cc with squish between 0.31 and 0.35 so the three saws stock all spec out very close.

 

[parrisw]

You should be able to weld thin gage with .060 filler, I have some .040 filler, but actually perfer to use .060 on 22 ga. I can turn the amperage up a bit and run a little faster than if I turn it down and use a smaller filler. Same with tungsten, I found it easier to weld with a larger diameter tungsten on light gage than to go with a smaller tungsten. I know it sounds crazy but try it, you can get more heat in faster to start your puddle and then you can go like hell rather than trying to drive the heat in the material and then go slow with the puddle.

Ya, I don't know, I tried to go faster, and just kept blowing through the muffler, I just couldn't get it to melt the filler properly, the dang muffler would just melt before the filler would.

 

[timberwolf]

I know exactly what you are saying there. When the filler is thicker than the base metal it is not like the book that says you make the puddle then stick the filler into it. I find it starts to be a bit more of running the arc from the puddle up onto the filler as you move forward and push the filler in. What say you Gink would that be a fair description?

 

[parrisw]

I know exactly what you are saying there. When the filler is thicker than the base metal it is not like the book that says you make the puddle then stick the filler into it. I find it starts to be a bit more of running the arc from the puddle up onto the filler as you move forward and push the filler in. What say you Gink would that be a fair description?

Ya, I hear ya! Frustrating to say the least!! Why not just use smaller filler, way easier.

 

[Zombiechopper]

try makin a ring of spot welds. Then put the fill rod away and just concentrate on pushin the puddle.

 

[angelo c]

Got to give away all the secrets eh!

1/16 is a bit thick, I can make do with it on mufflers but on pipes it makes a big weld, Here is my redneck engineering solution, mig filler is too floppy to deal with on it's own but twisting two 0.023 wires together with a drill makes it stiffer and it works quite nice.

TW, check out these twist pliers, made to safety wire parts on airplanes. should make your .023 wire braiding much easier.

http://www.amazon.com/Amazing-Safety-Wire-Twisting-Pliers/dp/B0000AXB5T

 

[timberwolf]

I make the twisted pairs ~50 feet at a time, run single strand out and back anchor it on the far end then clip it to chuck of hand drill, hold some tenssion and pull the trigger. Takes but a few seconds.

 

[parrisw]

TW, check out these twist pliers, made to safety wire parts on airplanes. should make your .023 wire braiding much easier.

http://www.amazon.com/Amazing-Safety-Wire-Twisting-Pliers/dp/B0000AXB5T

Problem with those it you can't do a really long section of wire with them, like you need for filler material. I'm sure the drill works just fine.

 

[AUSSIE1]

The aftermarket kits I've seen have had smaller transfers particularly the uppers.
Inside the 372 BB's lowers can be opened up with little work to match the opposite side. The OEM is no different here.

 

[gink595]

Ya, I don't know, I tried to go faster, and just kept blowing through the muffler, I just couldn't get it to melt the filler properly, the dang muffler would just melt before the filler would.

I know exactly what you are saying there. When the filler is thicker than the base metal it is not like the book that says you make the puddle then stick the filler into it. I find it starts to be a bit more of running the arc from the puddle up onto the filler as you move forward and push the filler in. What say you Gink would that be a fair description?

Hard to say, there is alot of variables to consider, experience, amperage, technique, type of filler rod and where you direct your arc. Also how the joint is prepared. I can do it fine with .060 filler, thats not to say I won't get a blow through here and there but that is typically due to inconsistent joint gaps, once I get started and get in the ryhthm of dipping the filler I can typically go for as long as I can feed the filler rod.

TW I do the same with concentrating on welding the puddle and filler rod and not worry about putting heat in the base metal, especially on thin 22-24 gage. When I start my weld I make a tack and almost a bridge just joining the two sides (butt joints) I then work the tack weld and add filler to that. I watch what I call the keyhole, the area in front of that weld, if I see that area creating a "hole" I will either back off the pedal and pull the tungsten back over the weld and then put my filler in that hole and then direct the arc over that area to fill the keyhole, just a back and forth motion. This is difficult to explain in text, not sure it makes much sense to anyone but me