The Forestry Forum

General Forestry => Chainsaws => Topic started by: nuke1 on October 29, 2015, 07:36:31 PM

Title: 359 porting
Post by: nuke1 on October 29, 2015, 07:36:31 PM
i was a dealer for the husky stihl echo brands , and my customers were mostly municipalities and school systems and as such for liability reasons we didn't do any modifications or porting now that I'm retired , I find myself with a brand-new 359 that's never been ran , and my neighbor a dried in the wool stihl  user !! wants to buy it  ,  my question would we benefit from doing any muffler porting on the saw , the only other husky he's ever used was a 257 and so he's going to put a 20 inch 3/8 on this saw , thanks
Title: Re: 359 porting
Post by: celliott on October 29, 2015, 08:32:46 PM
Yup, a dual port muffler will wake that saw up alot. If it's an etech model (green gas cap) it probably has a catalytic muffler. Get rid of that ASAP. Even if you don't want to modify it, get rid of the cat muffler.
There is also some  more easy power to be had on the 359. If you pull the cylinder, line the base gasket up to the cylinder. You'll see how much aluminum overlaps near the bottom of the jug\where the transfers feed upward. Knock that lip down (match to the gasket basically) helps them out alot too. It's kind of like it was intentionally de-tuned that way.

Of course the carb limiters will need to be pulled and the jets re-adjusted.
I did up a 359 like this- dual port muffler, knocked that restriction down, cleaned up the transfers and exhaust, and deleted the base gasket- that was a fun, strong saw. It impressed me! It pulled a 20" 3\8 no problem  :)
Title: Re: 359 porting
Post by: nuke1 on November 24, 2015, 12:21:39 AM
Thank you
Title: Re: 359 porting
Post by: ehp on November 24, 2015, 07:36:07 AM
359 is one of the most under rated saws out there , They really gain a ton of power by  muffler mod and porting of the cylinder .
Title: Re: 359 porting
Post by: weimedog on November 24, 2015, 10:35:32 AM
Quote from: nuke1 on October 29, 2015, 07:36:31 PM
i was a dealer for the husky stihl echo brands , and my customers were mostly municipalities and school systems and as such for liability reasons we didn't do any modifications or porting now that I'm retired , I find myself with a brand-new 359 that's never been ran , and my neighbor a dried in the wool stihl  user !! wants to buy it  ,  my question would we benefit from doing any muffler porting on the saw , the only other husky he's ever used was a 257 and so he's going to put a 20 inch 3/8 on this saw , thanks

I think before any mods are done check to make certain it has a steel clamp for the intake. Also they run well stock...Personally in that situation I wouldn't port it. Let him experience a reliable orange saw with the least variables possible for failure. Having it start easy, and run well over a long period of time is probably best for all involved. That along with a good sharp LGX or RS chain will make for a long term very nice saw. If its an expendable hobby saw...that's another story.

If he wants to spend another $200-$250 to have some one cut things up have that be his decision. Most stock saws can pick up power with a little more compression...and sometimes that's a really cheap and easy thing to accomplish. :) AND usually produces more tangible results (other than noise) than many muffler mods. Also there is the spark arrestor thing...especially in dry pine forests. Remember the old saw  "If you a hammer, everything looks like a nail".... guys out there with machining capability want to justify their existence... I say that understanding there are some builders who are good at what they do and really add power to those things...always a trade off. If you go that route, pick carefully and if you have skills to DIY that work, do a little research as each class of saws has their own quirks..:)
Title: Re: 359 porting
Post by: ZeroJunk on November 24, 2015, 02:25:57 PM
I kind of agree with weimedog. Unless you just like playing with your toys or are in production the amount of time involved actually cutting wood saved with a ported saw does not amount to much. Plus a 359 with a 20 inch bar will cut as fast as I want to cut anyway. Some of these hot rods cut faster than I can think.
Title: Re: 359 porting
Post by: ehp on November 24, 2015, 07:19:28 PM
the 359 done proper will out cut any stock 372 out there running a 20 inch bar , as far as trade offs go , there is none . A ported saw done correct will last and a ported 359 will out last a stock 359 . A stock 359 has some major engine defaults when produced that need to be corrected . I got guys still running 359's I built 10 years ago and not many stock 359's that have cut the same amount of wood . I'm not building saws for the pupil any more but still do stuff for friends and as far as what saw is better for me I will take a ported 359 over a ported 357 any day
Title: Re: 359 porting
Post by: weimedog on November 25, 2015, 01:04:57 AM
"If your a hammer"........ ::)
Title: Re: 359 porting
Post by: Spike60 on November 25, 2015, 04:56:40 PM
Quote from: ehp on November 24, 2015, 07:36:07 AM
359 is one of the most under rated saws out there , They really gain a ton of power by  muffler mod and porting of the cylinder .

Ed;

Do the stuffers in the 357 case make much difference one way or another for either the 357 or 359 top ends?
Title: Re: 359 porting
Post by: ehp on November 25, 2015, 07:10:32 PM
not like people think they do Spike , mostly its just Husky trying to blow smoke up your behind . I have taken stuffers off 357's and made more torque cause now the engine can move more air threw the transfer ports , Everyone thinks like all 2 strokes are built like a dirt bike motor which would be nice but a chainsaw motor is totally different and what works on say a Honda cr 250 doesnot work on a husky 359. In a chainsaw engine you need to more air and the way most crankcases are made its not so easy to do that as most crankcases are to tight in volume to move huge amount of air .
Title: Re: 359 porting
Post by: Spike60 on November 26, 2015, 08:32:23 AM
Thanks Ed; figured you might say something along those lines. I've gone both ways mixing and matching with this chassis. Just did a 357 on a 359 case and it surprised me how well it ran. I think that after porting the stuffers become more of a negative in the equation.
Title: Re: 359 porting
Post by: ehp on November 26, 2015, 05:56:07 PM
the hotter the saw the less they help ,
Title: Re: 359 porting
Post by: JohnG28 on November 26, 2015, 09:29:19 PM
Stuffers sort of seem like they would be counter productive in a smaller displacement saw where there is not as much crankcase volume to begin with. In a larger saw with a bigger bottom end I can see the gains in velocity perhaps helping more, but I can't say I know that for sure, just theory to me.
Title: Re: 359 porting
Post by: weimedog on November 27, 2015, 06:05:36 AM
Yea...dirt bike motors are usually...larger. More square. Much more crank case volume possible because they are...bigger. Lots more transfer port area relative to displacement. Lots and lots more flexibility with timing because they are...bigger AND reed valve designs in many cases "case reed" designs. Water cooling allows for much more heat/energy there for power to be managed. Expansion chambers instead of pressure cans. Much more intake (from reeds thru to air box) volume and latitude in shapes.) Power valves (real time modification of exhaust port geometry). Last but not least, designed to run at a wide variety of RPMs. Not a whole lot transfers to saw 2 strokes ... except one thing. Combustion chamber/squish type things. Common to all two stroke and a focus for most performance builds regardless of application.

I think the only other motorsport where chainsaw motor build logic translates is...RC toys,
Title: Re: 359 porting
Post by: Al_Smith on November 27, 2015, 07:33:18 AM
Quote from: weimedog on November 27, 2015, 06:05:36 AM
  I think the only other motorsport where chainsaw motor build logic translates is...RC toys,

A comment on that .RC sites and British motorcycle contain more information than all of the chainsaw sites combined .Chainsaw builders often seem  closed mouthed like it's top secret known only to them .Nothing could be farther from the truth in my opinion .Then again as been said before  there is more than one way to skin a cat ;)
Title: Re: 359 porting
Post by: ehp on November 27, 2015, 12:24:44 PM
nothing is a secret or top secret , biggest single thing is HEAT, heat tells you on how fast the engine will last , the more power it makes the more heat it has to get rid of . Common sense is a wonder full thing if used proper and just because someone says this is or how they do it doesnot mean its correct or its wrong