porting chainsaws

[husky 2100]

I am working on some saws for lumberjack comp. and was wondering if anyone could give me some input on what degrees to port them on. I am currently porting the ex. to begin to open at 84 degrees atdc and the intake to close at 85. Im fairly new to all this and thats what I was told worked best.

 

[Walt Galer]

Howdy Husky 2100,

Does that monicker mean you have the shakes? I remember that saw model as one you could fire up, set down, and it would beat you back to camp!

Regards,
Walt Galer

 

[husky 2100]

those old 2100s would beat you back to camp if didnt tie it down

 

[dozerdan]

a 285 piston and jug will bolt right in.I even have a 2100 with the 258 parts on it.
Later
Dan

 

[husky 2100]

what would the cubic in. be when you do that

 

[Gypo Logger]

This one beat me home tonight and was waiting at the door.
John

 

[tundraotto]

lol - thats gotta be the most beautiful saw i have ever seen..

 

[kdhotsaw]

Husky 2100 porting

Hello Husky 2100,
Excellent 6 cube saw to modify. Their getting a little hard to find anymore. If you didn't cut the top off the barrel and build a head thats too much exhaust. with the stock head it has a 11.5 cc combustion chamber volume. you need to build a cylinder head with around 6-7 cc combustion chamber volume . you'll then have a 9.5 corrected compression ratio. stock it has just under 6-1 corrected compression ratio. Included a picture of a modified 272 husky barrel. we've changed the transfer duration and shape and added a boost port for more transfer flow

Ken Dunn [email protected]

 

[Harley]

The boost port is the dogleg from the transfer port?
How deep is that, and how much does it help?

Harley

 

[kdhotsaw]

boost port

Hi Harley
The transfer ports on a chainsaw motor are way to small in area. the boost port s bring the transfer port area up to normal 2 stroke transfer area. makes more power. the newer huskys went to a quad port design,372's,385',s . they really flow more than the older design . a 372 just walks all over a 272 and the power increase is all in the transfer port design
ken

 

[kdhotsaw]

hello again harley,
the boosts are about 2.5mm deep and 8mm wide
ken

 

[husky 2100]

hello ken thanks for the info. i am putting heads on all my saws and doing the boost ports like yours. on the transers about what degree atdc do you do yours. i am currently doing mine to start to open 30 degrees after the ex starts to open. talking about the new cyl design i have a 346 xp i built last year for the 3 cub. class it has a head on it with a 314 hl running alchohol with 60% nitro and it seems like its going to do very well. RPM unlimited.

 

[kdhotsaw]

2100 husky

Hi H-2100
Thats a lot more transfer duration than we use but we cut 24-32 inch logs. you must be cutting 8 or 10 inch cants running a ten pin sprocket. we have to use less exhaust and transfer duration so we dont pull the saw down out of its power band.I have a 090 that we used menthonal with nitro . scary , it cut at 18500 and sounded like it was ready to grenade. only cut with it like that a couple of times but it was fast
Your post on the racing chain thread is right on the money but you must be willing to devote considerable time to filing chain to get where you can make fast chain
ken

 

[HUSKYMAN]

An 090 at 18500 rpms? Are you suicidal? Next time you do that you HAVE to get a video clip and sound bite of that. Every time I turn my computer on I can listen to a Stihl about to EXPLODE

 

[kdhotsaw]

090

Hello Huskyman,
Exactly right. My neighbor, a former husky dealer and chainsaw competitor who still runs his 460 maico hotsaw at some of our shows was helping me get the 090 ready, he just looked at me in disbelief on the first cut. then he ran in the shop and got my tack and checked the rpms before the second cut. we decieded to quit while the saw was still running. just used 50 percent menthonal and 50 percent racing fuel after that. but it was one awesome sound it made.
ken

 

[homelite360]

i owuld set that sound of a stihl blowing up as my start up sound on my computer. but that is ungoddly rpm's. how fast was it going through a cut?

 

[Walt Galer]

Howdy,

I have heard an honest 18,000 RPM from a saw motor only once. It was an SP-80 production saw, no mods, that had been sold in normal distribution to a logger, who had returned it to a dealer, who started it up, put it back in the box and returned it to McCulloch.

McCulloch in LA had set it up in their Eng. Lab. on a test stand, to show to a group of Manufacturer's reps from the industry lobby group, who were having a meeting in LA as guests of McCulloch. (I was in the group).

The crew at McCulloch put us all in the room and fired up the saw. After a very brief warm up, they firewalled the throttle. You should have seen the industry geniuses fighting for first through the door outa there! The sound was beyond belief. They had a strobe on the flywheel, with the cover cut away, and you could see the flywheel pulsate like it was jelly! I stood there and watched it like a ???? fool, almost by myself!

The story was it was an accidental stackup of tolerances that wound up in super tune condition. This is why no manufacturer will ever officially allow fooling with the port timing, by the way. If you happen to hit super tune, there is no theoretcal top end. She just winds up to grenade time. The original Stihl 050 would do this on occassion and I have vibratac'd them in the woods with loggers peaking at 17,000RPM. The Husky 180 could come close to 17,000, but the conrod would grow and allow the piston to hit the top of the cylinder. I saw this only once, at a dealer's shop. Not all saws of a model series would even come close to doing this. It required that stack-up of tolerances effect, so it was somewhat random for the given model.

Regards,
Walt Galer

 

[husky 2100]

hello kdhotsaw your right we cut 12in. round gum and poplar. so do you think the transfers will be ok like that or do i need a little more blowdown before they open. yea it does take lots of practice fileing Ive been doing it for about 10 years and still learning.