Ported Stihl 441

I have had this project in the works for some time now. I have been learning a lot from Erick about theories on what makes chainsaws works, as well as what makes them work better. With Brad's and Slinger's ported 441's out there, we decided it was time to get off the pot. We decided to do a nice, basic woods port on my 441. We got together, took it apart and stared at the jug with the extra split transfer ports for a good long while. This definitely helped



Compression was OK. It was 155 pounds cold. Squish band was 0.0295", which isn't too hateful.

We got the jug off and checked the numbers.
Bore: 50 mm
Stroke: 36 mm
Exhaust opening: 96 degrees (168 duration)
Transfers opening: 125 degrees (110 duration)
Intake opening: 80 degrees (160 duration)


I have a good buddy up in Cincinnati. He is a fantastic machinist, as well as a big fan of fat-bottomed girls. We made a trip up to see him and he promptly milled the jug down 0.0295" and made a 0.020" pop-up for the piston. This brought our squish down to 0.020 and brought up the compression nicely. Also, the jug itself was not square to the crank case. It was off by a few thousandths on the axis of the hinge pin, causing the piston to rock slightly every time it went up and down. Nik, of course, corrected this flaw from the factory. Now things are tight and moving in alignment. Andre, Mike and Brad made it a point to stop by, and we had a mini-GTG just shooting the bull while everyone got pop-ups made.

Nik (FATGUY)








Jug and Piston:




Andre (Andyshine77) and Erick (Erick) shootin the bull (Sorry Mike, I didn't get any pics of you and your lovely bride):




Brad (blsnelling) excited about his new pop-up:

After this, Erick began teaching me porting. He carved out one side of the port, then handed me the jug and said "do the same on the other side." Little did I know he had switched out from an aggressive carbide to a finishing carbide while I got him a beer. No 'oh-crap' moments, which I am happy about. Here are the pics of the stock jug:



Little closer:



I apologize, but I have no pics of the modified jug. I left the camera in the truck while at work, and since it was 15F outside, I think it drained the batteries down. Regardless, they were dead when we went to snap photos. Next time I have it apart, I will post pics.

The intake and exhaust went pretty effortlessly. The ring pin on the piston was located precisely so that we could not widen the exhaust port to one side. So, we were definitely limited there. We port matched the gaskets and heat shield to the muffler and called it done. The muffler got opened up quite a bit. We essentially made a square opening the exact same size as the exhaust port, then covered it with a screen. This allowed the original exhaust deflector to be used and looks fairly stock. Had we taken the muffler apart and put the screen on the inside, you probably couldn't tell it had been modded without looking closely (and the sound of course).



Erick slapped it back together, looked a few final touches over and let it idle for a tank of fuel to make sure nothing was gonna break when we finally let it rip. Compression was good (10 lbs let off between pulling the rope and getting the camera on the gauge - 180 lbs total).



So, we slapped a bar on it and called it done!




All I can say is wow.....

Erick really knows how to build a saw. With the original carb settings, it was 4-stroking at 14,500 RPM. After tweaking it a bit, it was still four stroking at 15,800 RPM - holy smokes! We never did take it all the way to the edge, but it sounded like it was gonna start 2-stroking shortly after 15,800. We ran the 20" bar on a 10" cant at 15,400 RPM, then set it rich to 14,700 and let the 32" bar eat fully buried. This saw runs better with the 8 pin rim now than it did stock with the 7 pin rim. It took about an hour to get the grin off my face. And to think, they said it couldn't be done...


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Sorry for the dark screen. It gets dark before we get off work, and we couldn't find Erick's shop lights. I increased the exposure a bit so you can see when the bar hits the cant.

Here are the official cut times:

stock 7 pin: 4.2, 4.0, 4.4 - 4.2 avg
ported 7 pin: 2.9, 2.9, 2.7 - 2.83 avg
ported 8 pin: 2.5, 2.4, 2.5 - 2.45 avg

ported 7 = 33% faster
ported 8 = 42% faster

Not seeing the pictures, but it looks and sound great in the video...Great job guys...

You guys did a great job. One of the better 441's I have seen.

Thanks alot Now I am going to have to port my 441! Steve

Awesome WK. Glad it worked out good for you. It's always interesting modding a certain model saw for the first time.

Am I the only one that can't see the pictures?...

They're fine here.

Wild knight: nice write up and vid. The pics aren't displaying but overall mission accomplished.

Wild Knight said:

Brad (blsnelling) excited about his new pop-up:

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Nice Brad, ALLWAYS raise the pinky finger when drinking!

My french Grandmammy always told me that. . .




So you let her idle for a full tank? I thought that was bad practice for a 2 stroker. . . I always "heat cycled them" 1: let it idle till you cant touch the cylinder. let her cool. 2:let her idle longer & open the throttle alittle. let her cool. 3: let her warm, hit the throttle alittle more. let her cool. 4: warm her, let her spin up. let her cool. 5: warm here & put her in wood. . .

I'm not even getting red x's...Just a blank white screen...Tried coping the link and still no go?...

Great thread!!


There's somethin' mighty fine to be said about them ported 441's.


Rock on!!! :greenchainsaw:

WoodChucker81 said:

Great thread!!


There's somethin' mighty fine to be said about them ported 441's.


Rock on!!! :greenchainsaw:

Click to expand...

So when's the race with the NY guys?

WoodChucker81 said:

Great thread!!


There's somethin' mighty fine to be said about them ported 441's.


Rock on!!! :greenchainsaw:

Click to expand...

I sure do likes me a fat bottomed girl.

blsnelling said:

So when's the race with the NY guys?

Click to expand...

:bringit:

nice......*tries to wipe smile off of face*....

I love the sound it makes.....and wide open too......gotsta get me one of those!!!!

Great write up Christopher. I had a great time spending the day with everyone. Looooong day.lol

Your saw look's awesome, maybe a little too awesom. My 372 is a little scared. I'm really impressed with the RPM's she's turning,:jawdrop: should make on hell of a firewood/cookie cutting saw.

Awesome job fella's

wow

Awesome job on the porting boys, I bet it'd hit 16000 before it started 2 stroking. It sounded just awesome in the wood! I fell in love with the 441 when you let me run it at Jeepers GTG, you cn only imagine how I feel about it now! It sure was a cool little mini-GTG. Anytime you get you guys, Andre, Mike, Sheila, Brad and myself in one place, it's a good time. Awesome write up and ty to you and Erick for keeping me in some mighty fine beer for a loooong time.

BTW, in case you all may be wondering, no cheese was hurt during the GTG.

I cant see any pics or red "X"s even. I looked last night and first thing this morning.......Steve