Modify Saw Muffler .... is It Worth It or Not and How To Do It ? ? ?

[Cut4fun]

Al I have actually started drilling the internal baffles out on some saws and leaving baffle in. On mufflers that was a 2 piece and needed the support between front cover to bolt up tight. Otherwise they would pull tight and collapse front cover or the muffler bolts would work lose sometimes.

[Al_Smith]

 I can't remember which saw but I had to use pieces of tubing in the place of the baffles so as not to collapse the front of the muffler . It worked .

[weimedog]

I will have do do as Al says on my 61 muffler to fit it to a 272 cylinder

[Al_Smith]

I think in this discussion of mufflers a point needs to be made for those with less experiance about their function, just as reference .

A majority of modern saw mufflers are what is refered to as "pressure cans " they hold a certain amount of volume and in function are actually a pressure regulating device .The baffles within them just bounce the sound waves or scatter them and they colide with one  another which effectively kind of cancels them out .Not entirely but to some degree .

In doing so though the flow of the exhaust is hindered and as such the incoming transfer portion of the engine is less than optimum for performance . Elimination or modification of these baffles will allow a more unhindered flow and as such produce a bit more power without doing a single thing to the rest of the engine other than perhaps enriching the carb because it will need more fuel .More fuel translates to more power .

Of course along with the baffle modification enlarging the actual exit hole allows for more fuel being transfered and thusly a more powerfull engine which effectively runs cooler .Real simple stuff if you think about it no rocket science involved at all . ;)

[weimedog]

First I have to again state I in no way consider myself to be an expert. I'm a hobbyist hack at best leaning my way to having fun with old saws..I wouldn't touch a new one myself and would never mess with anyone Else's saw!. Leave that to those who know what they are doing! Some people do cross word puzzles to pass time. I bring old Jonsereds, Homelites, and Husqvarna's back to life for my hobby. AND for entertainment at our GTG's mod some of my beater saws for kicks! Also I cut a lot of wood so I might as well make it a hobby..otherwise it would just be a chore! For by far the majority of saw users, stock is by far the best option. Don't mess with a saw unless its expendable, and by all means ignore some of the BS and Bling arguments used to justify spending time and money to hack up a perfectly good saw!

I think two other points need addressing if anyone takes the modification route...first and fore most forget about any warrentee you had after doing any type of modification to a new(er) saw! Also when tuning...don't pay attention to the one's who define success by how many RPM's that saw will turn no load...what counts is how well your saw holds those rpm's in a cut or if a modification allows your saw to now hold a higher RPM than before in the cut!

In that spirit, I like to tune to plug color vs. straight RPM's. Get the initial tune the conventional way..have it "4-stroke' a bit on top (or tach in my case). But really do plug checks after working the saw. I like to run a little rich on my work saws. So I tune my saws to where my plugs are on the darker side of tan..chocolate brown is where they are.

Another thing that can mouse up things are those RPM limited carbs and ignitions. You may think that "4-stroke" sound is the sound of your slightly rich mix on the high rpm's..and it could be your rpm limiting device instead and actually you are still too lean! ANOTHER reason plug checks are so important.

SO. Having said all that. I actually tune with a tach. And set even the modded saws I have to the stock recommended RPM's. Then do a little intuitive tuning along with plug checks to work from there.

(You can replace limited ignitions with unlimited ones..and you can disable the limited carbs as well...discussion for another person another time. I'd rather tune for more power in and around the Stock RPM range for my hobby woods ported saws)

[weimedog]

I will have do do as Al says on my 61 muffler to fit it to a 272 cylinder

[Al_Smith]

 I'm thinking that whatever saw I used the tubing trick on had  a one piece muffler that who ever built the thing had the bright idea it couldn't be tampered with .Hmm guess they never heard of Yankee ingenuity and a die grinder . :D

Now on other issues I agree with Walter ,don't follow everyones well intended advice if you don't know what you are doing . Get into it a little bit before you go to grinding away like a crazy man .By all  means fiddle with a freebie or several before you turn an 800 dollar saw into a door stop or anchor for a rowboat . Rome wasn't built in a day nor were good tuners .You have to walk first before you run . ;)

[ScottWojo]

What ever you need to know send me an email.  can provide you with tips,  materials and screen.

scott_wojtasik@hotmail.com

[beenthere]

Welcome ScottWojo

Tell us about the tips and materials.
Thanks.

[Sawz all]

Hello, my name is Kevin and this is my first post here at The Forestry Forum.  

I spent a lot of my time learning/building high performance work saws and worked very closley with people I consider to be top notch builders (over at racesaws). There were some really good/helpful people over on racesaws. I made some good friends! That being said, I have a very good understanding of what makes the whole package work.

IMO, if you leave a saw all restricted (without a muffler mod of any sort) the saw will work fine and last a manufacturer's life cycle. If you open up the muffler (mod it), even if you find little or no gains, the saw will breath better/run cooler and have a longer life cycle.  Keep in mind, some saws will have stronger gains than others as far as speed!

Scott Wojo is a friend of mine and he has made several mufflers for saws I have built. We are actually working together right now on a 359 Husky muffler modded/cyl ported saw. I had my friend Herb run a down up down in 10x10 pine and timed it. Next I had Scott build me a muffler to my specifications and ran the same test. The end result was only a hair faster with the modded muffler and a stock cylinder.

I am in the midst of porting this saw right now and in a few weeks I will have the timed cut for this saw with a ported cylinder and wojo muffler. All three of these tests I videoed and will share with you guys when done.

Kevin

[Cut4fun]

Hello, my name is Kevin and this is my first post here at The Forestry Forum.  

Hey Kevin long time.  In this thread you might see some info where I talk about that 266 I sent up to you and getting a like new 66 on a trade. You might be able to answer some of the questions I had.  https://forestryforum.com/board/index.php/topic,47753.0.html

Welcome,
Kevin

[weimedog]

I am in the midst of porting this saw right now and in a few weeks I will have the timed cut for this saw with a ported cylinder and wojo muffler. All three of these tests I videoed and will share with you guys when done.

Kevin

Have any pics of the porting & port timing numbers to share? That would be cool..especially if they are from the 200 series Husqvarna's

[Sawz all]

I just got home from work a little while ago.
I can tell you so far:
359 Husky stock timing nbrs
Ex 104*
X-fer 123*
IN 76* BTDC

Kevin

[weimedog]

Do you know the 272XP's? What would you want to change on that 357? Would you rather that intake be down into the 70 to 72 range?  123-104= 19, you going to do anything here? Just curious as some really get into the port timing game...to this point I usually don't and focus on cleaning & a little widening to what I can get away with based on piston skirts & blending so the transitions are smooth from component to component...but that's it..not an expert here. (ie. really don't know squat about changing port timing)


This is on my 272XP, this particular cylinder was built by a local guy who builds fast things for a living. I Did exactly this is on that 272XP cylinder on my 61 too (I don't  and won't do this for a living..only on my personal saws and race bikes)...the cleaned up exhaust and then matched to the exhaust stuff...(You might see the lightly modded transfer peeking out the bottom.)

[Al_Smith]

I can tell you so far:
359 Husky stock timing nbrs
Ex 104*
X-fer 123*

Kevin

Hmm "long" exhaust, short blow down .

[Sawz all]

weimedog,
Right off the bat I need you to understand I don't consider myself an expert and it takes a lot of trial and error to find numbers one likes. I don't want to come accross as a know it all, cuz I'm far from it...lol... That being said; I have done several 272xp's and the last one I did I think came out the best but only after finding out how it worked the other two ways (with different port timing nbrs I chose). Bottom line is all three came out good but the last one had the balance of power/torque I was looking for. I don't really feel comfortable telling you how to set up your saw(s) or how I'd do it. Especially being only on the sight for three days. As time goes on I'll share some things and hope to see other people trying things and all together we will all learn.

Getting set up with the correct porting equipment is an expensive investment in it's self.

On the 359, I am going to alter all three of those port nbrs.

STOCK 272
IN 69*
EX 102*
X-FER 127*
SQUISH .035

The one I liked the best I set up like this:
Ex- 97*
X-FER 118*
IN- 79*
and I forget if I had to make a base gasket or if I ran it w/out to aquir the squish I wanted.

Kevin

[Sawz all]

Hey Al,
Yeah, those are the nbrs.

I can tell you so far:
359 Husky stock timing nbrs
Ex 104*
X-fer 123*

Kevin

Hmm "long" exhaust, short blow down .

[Ecopsey]

I just got home from work a little while ago.
I can tell you so far:
359 Husky stock timing nbrs
Ex 104*
X-fer 123*
IN 76* BTDC

Kevin

Hi Kevin those are good #'s to work with for a "good" work saw .. 27* blow down is real nice wish they all had #'s like that.
Need any give me a shout.

[weimedog]

I appreciate the candor Saws all...and thanks for the tips & numbers. And it looks as if this thread has now attracted the attention of some real knowledge.

[Al_Smith]

27 would be but 19 most likely would not ---123 minus 104--19 ,unless I missed something  ???

[Ecopsey]

27 would be but 19 most likely would not ---123 minus 104--19 ,unless I missed something  ???

woops my bad sorry Al

[weimedog]

What would you recommend for a 272XP where it purpose is to do some work and to be fun at GTG's after the work is done...just a tad warmer than a pro's work "saw woods" port build?

(Al if you have pics you want put either in a gallery or have posted...email them and I'll build a thread you can add commentary to)

[Al_Smith]

I can't relate to a 272 because I've never worked on one .However the 038 Mag I reworked was right at 100 on the ex then I dropped the cylinder and it was around 102 .Somewhere around 22 blow down more or less .I ran it that way,oodles of power ,a little slow of speed but better than stock .

Soo back in I go,raise it to 94-96 or so that makes it like 28-30 blow down,okay now we got something--almost ---.Back in again and doctored on the upper transfers .That did the trick . There's more that could be done but not on that one .Another  is waiting in the wings for the next go round. The mood has not struck yet though . :D

[Al_Smith]

 :D We've got to stop here because we lost half the crowd in the first turn .

Oh my the subject was tuning in a muffler and before you know it we'll be babbling away about finger ports .

To those who just want to pep up the old saw,a simple rework of the muffler if nothing but pulling the screen helps and satisfies 90 percent of the folks without further ado .

Don't get too wound up about a few of us redneck half crazy grease monkeys that are about a half a bubble out of plumb to begin with . :D We just can't help ourselves .

[weimedog]

I agree. The thing that's becoming more and more apparent to me is the same things conceptually that worked on the old piston port motorcycles work here as well. (Minus the pipes & intake reed valves) Sort of a deja vu experience although the specific details related to specific saws is all new to me. New territory and fun as it's another learning curve to enjoy....

Gordon Jennings would be in hackers heaven here....Oh..By The Way:
http://www.datafan.com/TunersHandbook/2-strokefiltered.html