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General Forestry => Chainsaws => Topic started by: mad murdock on January 31, 2012, 10:59:56 PM

Title: Question about practical saw mods for more HP
Post by: mad murdock on January 31, 2012, 10:59:56 PM
I have a 372xpw and have been real happy with it, I have cut about 125-150mbf of logs with it, and milled maybe 3mbf of lumber with it on my AK mill. It has good power, but would be nice to tweak a little more power out of it for the milling. What percentages of hp increase could a guy reasonably expect from 1. Muffler mod(s) 2. Polishing port(s) 3. Big bore kit ?
Any better filter setup over factory on this saw to improve airflow to intake?
BTW running 28in bar and full skip full chisel chain for normal cutting and woodsman pro ripping chain(Oregon) for milling. 
Title: Re: Question about practical saw mods for more HP
Post by: AdkStihl on February 01, 2012, 09:06:29 AM
Sounds like its time for a 3120  ;D

You may see noticable gains by opening the exhaust a little? And smoothing out any casting/flash marks on the cylinder ports.

BTW...you never want to "polish" the intake port, actually you'd want it rough to help atomize the air/fuel mix.
Title: Re: Question about practical saw mods for more HP
Post by: JohnG28 on February 01, 2012, 10:38:23 PM
Big bore kit would definitely be a way to go.  No replacement for displacement. ;D
Title: Re: Question about practical saw mods for more HP
Post by: Al_Smith on February 02, 2012, 07:22:01 AM
Generally speaking just some work on the muffler will realize enough gains to satisfy most people .
Title: Re: Question about practical saw mods for more HP
Post by: nmurph on February 03, 2012, 07:34:43 PM
Quote from: Al_Smith on February 02, 2012, 07:22:01 AM
Generally speaking just some work on the muffler will realize enough gains to satisfy most people .

Aftermarket BB kits seldom yield more power. Husqvarna actually makes a 75cc version of the 372, but realistically, you need a bigger saw for milling. A muffler mod will increase power some, maybe 10-15%.
Title: Re: Question about practical saw mods for more HP
Post by: mad murdock on February 06, 2012, 12:24:32 PM
Thanks for the input gentlemen. I know for milling, a 3120 would be ideal, I will look into the exhaust/muffler mods. If I need more power, I probably will go with hydraulic power on the mill, and not go the expense of a larger chainsaw PH. Though I guess a guy could always look at the used old larger saws, that is a definite option as well.
Title: Re: Question about practical saw mods for more HP
Post by: drilldog on February 06, 2012, 02:54:22 PM
i have a 372xpg & did everything you mentioned. big bore kit, ported & polished and muffler mod. i also run the same bar & chain as you. i haven't done the math but i believe the big bore kit puts the saw @ 77cc. i too put a big bore kit on my bro-in-laws 044 mag. basically making it an 046. doing this definetly makes a noticable difference in power. 
Title: Re: Question about practical saw mods for more HP
Post by: mad murdock on February 06, 2012, 10:34:26 PM
Thanks drilldog. It is good to get real world reports from those who have "been there and done that"!
Title: Re: Question about practical saw mods for more HP
Post by: Al_Smith on February 06, 2012, 10:49:51 PM
I failed to see you were refering to chainsaw milling .On that there is no substitute for displacement .Next to stumping this is the hardest service you can subject a chainsaw to .
Title: Re: Question about practical saw mods for more HP
Post by: mad murdock on February 06, 2012, 11:52:50 PM
Quote from: Al_Smith on February 06, 2012, 10:49:51 PM
I failed to see you were refering to chainsaw milling .On that there is no substitute for displacement .Next to stumping this is the hardest service you can subject a chainsaw to .
Agreed Al.  I was researching old posts earlier today and noticed you have quite the collection!  I commend you on your resourcefulness and skill on some of your restore projects as well. Quite impressive. In your view if a
Guy was going to get a power head to mill with, what would be the most bang for the buck? An older Mac, say 125, or something made of less unobtainuim?
Title: Re: Question about practical saw mods for more HP
Post by: Ianab on February 07, 2012, 03:15:34 AM
I'd be looking at building something with a 4 stroke engine.

It can still be a chainsaw mill, but you have the torque and an engine that can run full load all day.

Ian
Title: Re: Question about practical saw mods for more HP
Post by: mad murdock on February 07, 2012, 06:36:12 AM
Good point Ian. Like some of the vertical shaft creatione some forumites have shared.
Title: Re: Question about practical saw mods for more HP
Post by: Al_Smith on February 07, 2012, 07:35:30 AM
Well yeah a 125 Mac ,Stihl 090/084/Ms 880 or Husqvarna 3120 would fill the ticket but no matter which one you choose you'd have a kings ransome in it .

There have been people who have used something like a 16 -18 HP vert shaft Briggs for a chain mill by using special large sprockets to get the chain speed up . I guess it works okay for them from what they say .

Fact some company makes a big slab mill which uses a vert shaft 4 cycle or the option of a 10 HP electric .They'll cut like 6 feet .Then again you'd have about the same price in one as would be in a small bandsaw mill .Depends on what you want to do I guess .
Title: Re: Question about practical saw mods for more HP
Post by: Al_Smith on February 07, 2012, 07:48:00 AM
I had toyed with the idea of building a chain mill basically using Alan Combs design for the carriage  but using a large 4 cycle .After consideration of probably 6-700 bucks just for a Cannon double bar in order to use a pilot bearing on the end and other factors that a bandmill would be a better option .

I settled in finally after much deliberation on a rubber tired bandsaw which is progressing  rapidly at the pace of an arthritic snail .

This is not to say that chain milling is all that bad just an option I tried once  a little bit and found out quickly it's not my cup of tea .Different strokes for different folks  ;D
Title: Re: Question about practical saw mods for more HP
Post by: mad murdock on March 21, 2012, 05:43:36 AM
Quote from: Al_Smith on February 07, 2012, 07:35:30 AM
Well yeah a 125 Mac ,Stihl 090/084/Ms 880 or Husqvarna 3120 would fill the ticket but no matter which one you choose you'd have a kings ransome in it .

I just picked up a Stihl 075av last evening for a good bargain. Will need some elbow grease, properly applied it should be a good start. (free is a good price)
Pics to follow.
Title: Re: Question about practical saw mods for more HP
Post by: Al_Smith on March 21, 2012, 12:44:37 PM
I've operated an 075 .They have plenty of grunt to mill with I'd say .Cheap is good free is a lot better . ;D
Title: Re: Question about practical saw mods for more HP
Post by: mad murdock on March 22, 2012, 02:31:26 PM
As promised a pic or 2 of the new (to me) saw
(https://forestryforum.com/gallery/albums/userpics/18691/photo2.JPG)

So far, I have cleaned the bar, soaking the chain in lube, and cleaned and blew out the saw.  It has spark, but is not getting to the plug,  either the plug is bad, or the lead.  will put a carb kit in it and an air cleaner.  Should come back to life ok.  The starter needed cleaning, and lube, and all is ok.  A little water in the oil tank, as well as old oil  the manual pump works, well, the oiler adjust lever is limber, will have to wait and see if the auto oiler will need any work, or if it is ok.  The saw looks like either a late model 075, or something,  it has a 076 style handguard mount on top of the oil tank. mebbe that was standard for the full wrap handle models? 
(https://forestryforum.com/gallery/albums/userpics/18691/photo.JPG)

a pic of the other side.
Title: Re: Question about practical saw mods for more HP
Post by: Al_Smith on March 23, 2012, 06:03:09 AM
You're in the right region to find big saws . They exist but are a rarity in these parts .
Title: Re: Question about practical saw mods for more HP
Post by: Clam77 on March 23, 2012, 11:19:02 PM
Even rarer here...  I'd LOVE to get my hands on one to fix up and play around with... for a good price of course..   :D
Title: Re: Question about practical saw mods for more HP
Post by: sawguy21 on March 23, 2012, 11:33:35 PM
My hands ache just looking at that beast. :D I remember trying to get them started after the chain oil leaked into the crank case. OUCH!!!