Stihl 361 Junkyard Zombie Mutant

[bogieboy]

Not knowing you or your chainsaw experience from Adam, i wanna point out something i see...i zoomed way in on your video, your chain appears to have a slightly rolled edge... the cutter might be sharp, but the top plate isnt flat yet, so its not gonna cut well....least thats what i see, maybe the camera is lying to me? See the shiny spot? The top of the cutter should all reflect as one surface, but this has a secondary reflection right at the cutting face of the cutter......i dipped the tip of my 661s bar in the dirt last week, and it looked the same... cut great, but slower in the cut, still threw giant chips (even dull 404 square ground will do that with a ported 661 )

Might be worth throwing a new chain on just to see before chasing a bunch of other gremlins that arent there and were caused by an overheating saw?






again, i could be completely wrong, cameras play tricks on us all the time... LOL some fresh chain still on the roll for comparison(stihl 33rs is the bottom cutter, and the top one is actually a chinese copy)

 

[Ketchup]

What are the port timing numbers? And have you put a timing light on it to check ignition timing?

Current Numbers:

Intake 76

Exhaust 101

Transfer 123/126

I don’t know compression yet but it’s inconveniently high. (That may be part of the heat). I have not tested ignition timing. (Also part of the heat).

My gut says raise the exhaust and transfers. It’s an 82cc saw with lots of compression. Easier pull and more speed sounds good.

 

[Ketchup]

Not knowing you or your chainsaw experience from Adam, i wanna point out something i see...i zoomed way in on your video, your chain appears to have a slightly rolled edge... the cutter might be sharp, but the top plate isnt flat yet, so its not gonna cut well....least thats what i see, maybe the camera is lying to me? See the shiny spot? The top of the cutter should all reflect as one surface, but this has a secondary reflection right at the cutting face of the cutter......i dipped the tip of my 661s bar in the dirt last week, and it looked the same... cut great, but slower in the cut, still threw giant chips (even dull 404 square ground will do that with a ported 661 )

Might be worth throwing a new chain on just to see before chasing a bunch of other gremlins that arent there and were caused by an overheating saw?



View attachment 421212


again, i could be completely wrong, cameras play tricks on us all the time... LOL some fresh chain still on the roll for comparison(stihl 33rs is the bottom cutter, and the top one is actually a chinese copy)

View attachment 421214

I’ll take a look but I’m pretty sure the video is creating an illusion. Yes, if the top plate was that deformed that would be a problem. The main thing that jumps out about the chain is that it’s got brown residue on it like it’s burning the wood. Classic sign of a dull chain, but in this case the actual edge is surprisingly good. To me that indicates an oiling problem.

Not much time for this saw right now. We’re slammed at work.

 

[Mastermind]

Current Numbers:

Intake 76

Exhaust 101

Transfer 123/126

I don’t know compression yet but it’s inconveniently high. (That may be part of the heat). I have not tested ignition timing. (Also part of the heat).

My gut says raise the exhaust and transfers. It’s an 82cc saw with lots of compression. Easier pull and more speed sounds good.

Take .015 - .020 off the top of the piston. That will tell you a lot about which direction you need to go.

 

[bogieboy]

I’ll take a look but I’m pretty sure the video is creating an illusion. Yes, if the top plate was that deformed that would be a problem. The main thing that jumps out about the chain is that it’s got brown residue on it like it’s burning the wood. Classic sign of a dull chain, but in this case the actual edge is surprisingly good. To me that indicates an oiling problem.

Not much time for this saw right now. We’re slammed at work.

That could just be from resins in the wood... this is my neotec chain on my 044, has a resin buildup, was cutting ash with it last. If it gets much darker than that, then you should be looking into sharpness.. carmel color like this is normal buildup (at least in my experience)

Thats a 25" bar on 044 with the oiler all the way up, running stihl woodcutter btw.

 

[davidwyby]

My chains almost always have on them

 

[Maintenance Chief]

The oiler affects cutting a hell of a lot! I've accidentally run out of oil enough to know It'll stop my pm700 in a 12" stump or my 394xp in a cut.
Gotta get that sucker slinging!

 

[Ketchup]

Seems to be oiling just fine. Teeth are sharpish. Pretty sure it’s the numbers.




Right now it feels similar to my ported 7910. Strong but not fast. Pulls over hard.

 

[farminkarman]

Seems to be oiling just fine. Teeth are sharpish. Pretty sure it’s the numbers.

View attachment 421386
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Right now it feels similar to my ported 7910. Strong but not fast. Pulls over hard.

Try leaving the exhaust alone first and raise your transfers a couple degrees and see how it feels.

 

[Mastermind]

Too much compression can absolutely hurt performance...and bad. What's it blowing on a gauge?

 

[Ketchup]

Try leaving the exhaust alone first and raise your transfers a couple degrees and see how it feels.

That makes sense. Randy’s suggestion to shave the piston got me thinking. I’m going to stack gaskets and see what changes I get.

There’s a fair bit of work in that piston and the jug base is pretty thin already.

But if the gasket trick doesn’t tell me anything I’ll flatten the exhaust at 122.

 

[Ketchup]

Too much compression can absolutely hurt performance...and bad. What's it blowing on a gauge?

Ima find out tonight. Feels well above 200.

 

[Powerstroke Cowboy]

What's it blowing on a gauge?

The breath test should be fine as long as Caleb's not feeding it ethanol gas.....



My sorry attempt at humor.... LOL


To much blow down will make a saw slower/sluggish.

I sure there's more in this thing.

I like your plan of running a thicker base gasket to simulate raising the exhaust and transfers Caleb. It will also give you more case compression.

 

[thedude74]

How do you like the Clone? I’m thinking of buying one to do a cleaner version of this build.

I also think a 362 is worth examining. If it could house a 441 crank the whole build would be more heavy duty. The 440 crank is a cupcake. Late 362 has a better filter setup as well.

The clone has been good overall once sorted out. Lost a clutch spring after maybe ten tanks. The chain tensioner threads were messed up from the get go. A carb screw was also stripped. The nylon filter let's some fines through....not terrible though.
Minor stuff really.
All the other parts are pretty decent. Minus some rough edges at the tank seams and what not it's very close to OEM Stihl.

Overall it would be a good low cost candidate for a hybrid build. Most the parts can be purchased individually if you were just looking to upgrade some worn OEM stuff.

I don't think the ms362 is available in clone form as of yet. Could be wrong? I agree with you on the late model filter. That would be a big improvement.

 

[thedude74]

Good to see your progress. It will be interesting to see the results of the double base gasket. A cheap piston would be nice to grind on and play with port timing.

 

[Ketchup]

Good to see your progress. It will be interesting to see the results of the double base gasket. A cheap piston would be nice to grind on and play with port timing.

I have cheap pistons, but I have to slot them to fit the rod and trim the skirts plus any grinding I want to do on the windows. It’s the time I would rather avoid.

 

[thedude74]

I have cheap pistons, but I have to slot them to fit the rod and trim the skirts plus any grinding I want to do on the windows. It’s the time I would rather avoid.

Oh yeah. I didn't think of that.

 

[Ketchup]

Comp tests aren’t trustworthy for a lot of reasons. First pic is at my house (9400’), second is down in town (5650’). I think at sea level it would be higher. It’s kind of awful to pull over right now. I think these are low readings. I could have squeaked a few more PSI out of both, but I’m a wuss.

 

[farminkarman]

Comp tests aren’t trustworthy for a lot of reasons. First pic is at my house (9400’), second is down in town (5650’). I think at sea level it would be higher. It’s kind of awful to pull over right now. I think these are low readings. I could have squeaked a few more PSI out of both, but I’m a wuss.
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View attachment 421496

205 psi at 5600’ is in the realm of “too much compression” in my opinion. That would be around 240 at sea level. One of the first saws I did machine work on is a Poulan…that thing blows like 225 at my elevation of 800ish ‘. I haven’t gotten it to run right….some day I will get back to it and fix it.

 

[drf256]

Caleb, is there a reason you went with a 54mm big bore cylinder instead of a 52mm OEM one?

I think you have a metric *s-wordton of case compression, so I would want your uppers more numerically higher than usual so that you don’t over scavenge. Pretty much the same thinking as doing a 446 hybrid. Good numbers for a 446 vs a 460 are quite different. I usually want more BD on the 446.

It would be quite interesting to know where your ignition timing is. To reduce compression, you could add another angle in the band up towards the chamber and then hand blend it. I still believe that dishing a piston after the squish band interface shouldn’t affect scavenging much. Even Husky decided to do it on the newer 562.

You have increased heat from all that compression and fin area reduction. The 036 flywheel may be adding to the mismatch. I wonder if the ignition timing is as well.

As you know, stacking gaskets is going to change many things at once. It’s too bad it’s not a 52mm, where you would have readily available slugs to play with. My gut tells me you need more intake and exhaust duration, and the uppers need to come up a bit. I was thinking 99/122/78.

Saw sounds pretty damn good in that last video. Thanks for taking the time to do this.