# Modifying Stihl 036 Pro (port, muffler, etc.)



## Ashful (Oct 24, 2018)

Continuing on from a tangent in another thread... I have an Stihl 036 Pro with very low hours on it.  I rarely use it, primarily because it’s so much slower than my other saw.  Yes, it is wearing a nice new bar, sharp chain, and is properly tuned... it’s just a little low on displacement for my preferences.

Time for some modding fun.  Where to start... where to end?  Goal is maximum horsepower, without killing it.  Cost and noise level are not enormous concerns.  It needs to start and run in weather that’s 10F to 85F, without enormous trouble.


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## salecker (Oct 24, 2018)

Send the saw to Tree Monkey. You will get the best bang for your buck and end up with a saw that is reliable.And meet all of your goals.
 Or you can experiment with a gorgeous saw and potentially wreck it,if you are unfamiliar with the use of a right angle hand piece fordome and a lathe.Or do you have those tools?Without them you will not achieve your goals.
 You can open up the muffler,and get rid of the base gasket and advance the timing with basic tools,don't forget to re-tune the carb.


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## Ashful (Oct 24, 2018)

Got access to a full machine shop, here.  Old motor head, just never messed with chainsaws.  Started rebuilding old lawnmower engines and modifying my own go-cart engines at age 8, moved into small block Chevy, then big block Ford.  Used to build at least one engine ground-up per year.  Done various combos of squishing / porting / polishing / muffler mods on everything from flatheads to small blocks... just never 2-stroke.

Been doing a little reading specific to the 036, what gains people have seen from that specific model, and it looks like the first order of business here will be opening up the muffler.  Gotta think about the ergonomics of adding a second port to the left side, versus just opening up the factory port, versus venting out the front with a welded deflector.

I wouldn’t mind sending a saw to Tree Monkey, but that effort might be wasted on a lowly 036, and most of those guys seem to be running real long turn-around times.


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## woodhog73 (Oct 24, 2018)

I don’t think the effort on your 036 would be wasted  if you intend to use the saw. Especially if the saw is low hours and in good shape.  The 036 is a light saw for what it is and Id say a pretty easy to use all day saw that doesn’t get heavy as the day gets long. so if you want a lighter saw and are not happy with what it’s currently doing now I’d say go for it. 

You might have read in a recent post of mine that I had a 50cc saw ported and muffler modded. I had a couple friends telling me it was a waste of time and to just run my bigger saws. But I have a bad back that gets sore very easy and the light weight helps me. But like you said about your 036, I felt my 50cc was “ slow “ and I wanted something more powerful without any extra weight. I did not regret it. I can’t put real numbers out there as to the gains I picked up but its noticeable. It cuts better than most 60cc saws and it’s been very reliable. No it won’t pull a long bar but it does 90 percent of what I need with an 18 inch bar. And I don’t get tired running it all day long. 

I had a local guy who builds snow mobile and atv racing type engines do it for me. It was a risk but unlike snow mobiles and motorcycles , chainsaws only need to run wide open. You don’t have to worry about porting for low end, mid range, etc. so this guy was able to do a decent job even though he doesn’t specialize in chainsaws. 

Does your 036 have a restricted spark arrestor screen on it ? Just by simply removing the spark arrestor and retuning you will pick up a small gain.


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## Ashful (Oct 24, 2018)

Awesome, thanks woodhog.  I assume it has a spark arrestor, I thought all of the Stihl 0xx’s did, from the factory.  I’d probably feel safer adding a second (or enlarging the first) port, and keeping the screen, whether it’s warranted or not.  Things can get quite dry here, some summers, and I tend to use this saw around firewood.  [emoji6]

Found an old post from MasterMech (actually, in reference to my same 036) suggesting I open the muffler outlet (or create a second port) to about 80% of inlet cross section.


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## woodhog73 (Oct 24, 2018)

Ashful said:


> I assume it has a spark arrestor, I thought all of the Stihl 0xx’s did, from the factory.  I’d probably feel safer adding a second (or enlarging the first) port, and keeping the screen, whether it’s warranted or not.  Things can get quite dry here, some summers, and I tend to use this saw around firewood.  [emoji6]



I can understand why you would want to keep the spark arrestor. I had a spark arrestor get clogged with oil and carbon build up on a 2 stroke weed whip and I didn’t notice until the whip wouldn’t run at all above an idle. So I assumed it started loosing power months before but was so gradual I didn’t notice. I imagine some folks are probably using saws with partially clogged arrestors and might not know it and it’s robbing high rpm power. 

Good luck with the 036. Sounds like your going to port it yourself ? Will be interested after it’s done to hear from you on how it runs.


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## Ashful (Oct 24, 2018)

I’m going to do the muffler mod myself.  Too easy not to.  After that, I’ll have to do some research, to determine whether it’s worth actually doing any porting work myself, or sending it to someone with experience.  I’m getting the sense, from reading old posts on a few other forums, that other than the muffler being a little restrictive, the rest of the 036 is actually set up pretty well out of the box.  Apparently one of Stihl’s better efforts, from their pro lineup.  In other words, there’s something to be gained from the muffler mod, but much less from the (more difficult) porting and other typical mod’s.

One other interesting thing I came across was the high level of disappointment in the modern 66x saws.  Not nearly as fast and strong as the old 066’s and 064’s.  Bummer, as I’d been toying with the idea of picking up a new 66x this winter.  Countless comments from old 066 owners, on what a dog the 661 is, by comparison to the saw it replaced.


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## Diabel (Oct 24, 2018)

I was about to ship you my 360. You like doing things in twos...
Bummer.


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## Ashful (Oct 24, 2018)

Diabel said:


> I was about to ship you my 360. You like doing things in twos...
> Bummer.


Sure, I'll practice on yours!


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## Jazzberry (Oct 25, 2018)

I have opened the muffler up on several saws and my 360 was the least responsive of all of them. I think the stock 360 muffler must be doing a fairly good job at least it was on my MS 360 Pro.


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## JimBear (Oct 25, 2018)

There are a lot of quality saw porters out there. I think from what I could tell $300 - $325 is the going rate for porting. Shipping is an added expense to keep in mind. The 45 min drive down to Miller Mod Saws was worth it to me & Carl was very friendly & has kept me updated on everything going on with both my saws, pics of the p/c, what options I had for replacement parts, costs, etc. If you have Facebook Carl posts videos of his modded saws in action during their test cuts. Just look up Miller Mod Saws Ravenwood, MO on an internet search & it will pop up. There is also a builder review section over on the OPE site.


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## Ashful (Oct 25, 2018)

Jazzberry said:


> I have opened the muffler up on several saws and my 360 was the least responsive of all of them. I think the stock 360 muffler must be doing a fairly good job at least it was on my MS 360 Pro.



Maybe the 360 has other bottlenecks.  ;-)

All reports I’ve read on the 036 indicate the muffler is the primary limiting factor on making more power.  Other things have shown gains, as well, but nothing approaching the bang for buck of the muffler mod.  All of these things vary by model, and what compromises the original engineers made to meet their requirements, obviously.


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## salecker (Oct 25, 2018)

Ashful said:


> I’m going to do the muffler mod myself.  Too easy not to.  After that, I’ll have to do some research, to determine whether it’s worth actually doing any porting work myself, or sending it to someone with experience.  I’m getting the sense, from reading old posts on a few other forums, that other than the muffler being a little restrictive, the rest of the 036 is actually set up pretty well out of the box.  Apparently one of Stihl’s better efforts, from their pro lineup.  In other words, there’s something to be gained from the muffler mod, but much less from the (more difficult) porting and other typical mod’s.
> 
> One other interesting thing I came across was the high level of disappointment in the modern 66x saws.  Not nearly as fast and strong as the old 066’s and 064’s.  Bummer, as I’d been toying with the idea of picking up a new 66x this winter.  Countless comments from old 066 owners, on what a dog the 661 is, by comparison to the saw it replaced.


Funny i have read the opposite,one guy has had 16 661's and says he would never go back to the older saws.I have one in a box so i can't give my opinion.The new 462 looks like a winner,small package and light.Seen one sitting next to a new 261 and there wasn't much size difference.
I have 3 064's and 2 066's.One 064 has a 066 ported cylinder.Maybe one day i will get a chance to do a head to head to see which one works best for me.
 If i was on a job where the saw mattered it would be a new 661.


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## Ashful (Oct 25, 2018)

salecker said:


> Funny i have read the opposite,one guy has had 16 661's and says he would never go back to the older saws.I have one in a box so i can't give my opinion.The new 462 looks like a winner,small package and light.Seen one sitting next to a new 261 and there wasn't much size difference.
> I have 3 064's and 2 066's.One 064 has a 066 ported cylinder.Maybe one day i will get a chance to do a head to head to see which one works best for me.
> If i was on a job where the saw mattered it would be a new 661.



I had been thinking the same, which is why I was toying with updating my 064 to a 661, but now I’m having second thoughts.  Arboristsite is filled with negative reviews of the 661, from a lot of guys who previously ran 066’s, so they have a good basis for comparison.  The word “gutless” comes up, frequently.

I wonder if there have been changes within that model number, over the last year or two, that have caused this?


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## JRHAWK9 (Oct 25, 2018)

salecker said:


> Send the saw to Tree Monkey. You will get the best bang for your buck and end up with a saw that is reliable.And meet all of your goals.
> .




yep, Scott knows his stuff!  I've got two of his saws.


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## woodhog73 (Oct 25, 2018)

I gotta believe a muffler mod will make some gains. Like I said a few posts back simply removing the spark arrestor screen on any saw will give a very small gain ( I know you want to keep the spark arrestor ). For giggles take it out and blow thru the screen. It’s fairly constrictive which you will notice when blowing on it. So I have to imagine if you open the muffler up and drill some ports it will help. If someone takes just the spark arrestor out they need to retune. Makes sense if your cutting in winter with snow on the ground or in spring when the woods are wet enough. 

As for the question as to should you get a new 661. Well it might be a higher rpm and narrower powerband than your 066 but a couple perks include the much improved air filter and intake system. stays cleaner longer fresh air from the non drive side. Also  the spring anti vibe is nice.  And the mtronic is also a benefit in my opinion.

Most people who don’t like mtronic or auto tune say they don’t like them probably because they haven’t used one. First time you use the new 661 on a hot humid summer day and realize the saw runs flawlessly without needing any tuning from its previous winter tune for frozen temps it might make you a believer.


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## Ashful (Oct 25, 2018)

Yeah, I really like the whole MTronic concept.  Brilliant.   I know there were some hiccups early on, not that different than the progression from carburetor to fuel injection in our daily drivers.

Some of the complaints about the 661 linked the lack of power to emissions requirements.

On spark arrestors, my thinking is they reduce the outlet port cross section by some percentage, maybe 30%.  So, it should be possible to compensate by making your ports that much bigger, than if you had no spark arrestor.  Then it’s just a matter of keeping them clean, which may be where my plan goes awry.  It’s possible the spark arrestors clog more quickly on mod’d saws, due to the lower velocity thru them and higher fuel consumption.


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## woodhog73 (Oct 25, 2018)

I like your theory on modding the muffler to compensate for the spark arrestor. I also respect that you want to keep it. No sense in burning your property and house down if your cutting in summer and dry conditions. 

Just a side thought. The only spark arrestor I had clogged was on a weed whip. But I was running it 1/2 to 3/4 throttle to help with the pebbles and grass flying back at my legs. Slower string speed less crap hitting my legs. I think that’s why it clogged.

 But With a saw assuming your running it full throttle all the time ( modded or not ) I think the arrestor screen stays cleaner longer. Ofcourse your pre mix ratio and tuning on the saw play a role too. But for the most part the screen probably stays cleaner longer in a well tuned saw running wide open.


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## salecker (Oct 26, 2018)

Personally...
I used to be dead set against anything computer controlled.Mostly because it is a world that i know little about.And i was hoping computers were a fad.
I am opening my mind to accept computers and will be learning more about them.The main reason is that it dosn't look like they are going away,and i am being left behind with my club and round rock that i use to move things around.
 Seriously i will always opt for non computer controlled equipment for myself. But for production work where anyone is using equipment then computer controlled is the way to go.
 I will always be hands on and fix my own stuff.At the moment i am at a disadvantage by keeping my head in the sand and ignoring computers,this gives my competitors a leg up on my company.
 So i have to adapt with modern times,but should the computers die off in a eprom bomb attack i will be ready with my army of carburated equipment.


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## Ashful (Oct 26, 2018)

salecker said:


> ...i was hoping computers were a fad... it dosn't look like they are going away,and i am being left behind with my club and round rock that i use to move things around.



Well, at least you are in good company.

“I think there is a world market for maybe five computers.”
_Thomas Watson, President of IBM, 1943_

“There is no reason anyone would want a computer in their home.”
_Ken Olsen, founder of DEC, 1977_

... and while I was looking up the dates on those two perennials, I came across this unrelated gem:

“Nuclear-powered vacuum cleaners will probably be a reality within ten years”
_Alex Lewyt, President of Lewyt Vacuum Cleaners, 1955_


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## salecker (Oct 27, 2018)

Ashful said:


> Well, at least you are in good company.
> 
> “I think there is a world market for maybe five computers.”
> _Thomas Watson, President of IBM, 1943_
> ...


I heard that Warren Buffet uses a flip phone...
Started a new part time job yesterday and was assigned a smart phone for the next 3 years,so the learning has begun.My staff and coworkers are very supportive of my shortfalls on the tech side of things and will help bring me into the tech age.One coworker chucked as she pointed out that she had taught Computers for the seniors and would be willing to teach me, she is pregnant has lots of time on her hands so i will take her up on the offer.
 I will be getting my own smartphone as well,not sure when yet or what phone i will get.But the criteria will be the smallest one i can find.My real job makes it tough for me to have anything that dosn't fit in my pants pocket.
 Oh yes to keep on track i will be sending my 361 out for porting if it passes the porters criteria.He now only does new saws,but i do have a credit for one port job from before his new saw only rule.


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## jetsam (Oct 27, 2018)

Ashful said:


> Well, at least you are in good company.



These days, there's also lots of bad company.

I grew up before there was an internet or cell phones, and I marvel at all the people who blunder around in the dark, not knowing how to do stuff and being locked out of the information age because they choose to be.   (You know what's "too complicated"? Having to drive a car to the hardware store to ask a 16-year-old how something works, while your 8-year old snickers at you because they Googled it in the first 30 seconds of the car ride.)

I see that group as seriously handicapped; I can't imagine how it looks to the young people who have always had the internet at their fingertips.  I doubt "disabled" covers it.

We old farts had better join 'em, because we're not going to be beating 'em.


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## Ashful (Oct 28, 2018)

I don’t know, sometimes I envy them.  [emoji1]


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## jetsam (Oct 28, 2018)

Ashful said:


> .
> On spark arrestors, my thinking is they reduce the outlet port cross section by some percentage, maybe 30%.  So, it should be possible to compensate by making your ports that much bigger, than if you had no spark arrestor.  Then it’s just a matter of keeping them clean, which may be where my plan goes awry.  It’s possible the spark arrestors clog more quickly on mod’d saws, due to the lower velocity thru them and higher fuel consumption.



SO what you need is a scheme that allows for a large cross-section spark arrestor without restricting exhaust flow too much?







Just put some threads and a screen in the middle and you are good to go!


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## JimBear (Oct 28, 2018)

Jetsam you must of been at a get together somewhere to witness something like that? Lol


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## Ashful (Oct 28, 2018)

That’s one heck of a Quick Stix.


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## jetsam (Oct 28, 2018)

JimBear said:


> Jetsam you must of been at a get together somewhere to witness something like that? Lol



No, but it sounds fun. I just Google image searched it.

If you want to take it further, Google for  "chainsaw racing".


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## jrems (Oct 28, 2018)

I can build you one of these if you really want. 
Here is my build thread. 
http://opeforum.com/threads/stihl-036-044-hybrid-build.12242/


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## showrguy (Oct 28, 2018)

Ashful, you can remove the spark screen, enlarge existing opening, then reinstall the screen, easy enough to do.. Faster up carb a little, go cut..


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## Jazzberry (Oct 28, 2018)

showrguy said:


> Ashful, you can remove the spark screen, enlarge existing opening, then reinstall the screen, easy enough to do.. Faster up carb a little, go cut..




I remember when I did my 360 I researched it and there was a specific amount to open it up. I don't remember what it was it was a while ago but I would do some research before I started cutting. Then again my results were not that impressive lol at least on my 360. Other saws responded better. With a 200/020 all you have to do is remove the screen and it will feel like someone stuck a supercharger on it.


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## showrguy (Oct 28, 2018)

Jazzberry said:


> I remember when I did my 360 I researched it and there was a specific amount to open it up. I don't remember what it was it was a while ago but I would do some research before I started cutting. Then again my results were not that impressive lol at least on my 360. Other saws responded better. With a 200/020 all you have to do is remove the screen and it will feel like someone stuck a supercharger on it.


No more than 80% of exhaust port opening, if I remember right..
You could'nt get 80% using the stock location anyway..


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## Ashful (Oct 28, 2018)

showrguy said:


> No more than 80% of exhaust port opening, if I remember right..
> You could'nt get 80% using the stock location anyway..



Yeah, that’s my target.  Will be achieved by combination of opening stock port and adding a second port, screen, and deflector on other side.  I will actually overshoot the 80%, by whatever I determine the screen’s fractional reduction to be.


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