2100 husky with a 3120 heart

[rupedoggy]

After looking at this project for months I finally put it together. If you want to stroke your 2100 I will tell you what to do. Put that 3120 crankshaft in your lathe and take a little off each side (near the counterweigh cheek) until it is the same width as the stock 2100. Radius the sharp edge out so you don't get stress risers. The bearings are from a 2100. The piston is a 394 with two base gaskets under the cylinder. The rest is to just assemble with 2100 parts. Everything fits! Even the keyway is in the right place for correct ignition timing. Oh the inside of the crankcase is close to interference with the counterweights, but it cleared on mine. Now one of you math types please tell me the displacement. Mike

 

[BIGBORE577]

Mike,
That sounds way cool! Let us know how it runs!

Jay

 

[little possum]

So did you use the 394 piston in the 2100 cylinder?

What kind of RPMs does it turn, wasnt the 2100 limited?

And like Jay said, let us know. Sounds very interesting.

 

[nmurph]

need some vids!!!!!

 

[rupedoggy]

Can't do vids but heck you have seen chain saws cut before.
Yes the 394 piston in the 2100 cylinder. The 394 piston is shorter so you don't have to do machine work to get it to fit. I left everything stock so I could get a baseline idea. Will be out of town this weekend but will get back later. Mike

 

[eyolf]

Bore 56mm
Stroke 42mm

Pi times bore radius, squared, times stroke, all divided by 1000.

103.4 cc

Regular 2100 was 56x40, 98.5 cc so 2mm increased stroke yield about 5 cc's bigger

 

[rupedoggy]

Wow a lot of work for 5cc!

 

[Jacob J.]

Even so, that 5cc might make the difference in a close race. That is a cool project for sure...

 

[nmurph]

Wow a lot of work for 5cc!

yes, but you also used some creativity and engineering. bet there are too many like your's around.

 

[BIGBORE577]

yes, but you also used some creativity and engineering. bet there are too many like your's around.

well said.

 

[BIGBORE577]

I know it's only a 5cc increase. However, because it's due to the lengthening of the stroke, couldn't it change the characteristics of the saw all together? More so than if the 5cc change was due to an increase in just the bore?

 

[7oaks]

Could you do this same conversion if you put a 2100 cylinder on a 285CD? That would be a considerable step up!

 

[AUSSIE1]

Longer stroke usually means more torque. It would be a grunter.

My 395BB is 58mm x 38mm = 100.4cc

 

[Jacob J.]

Dolmar had the long stroke lesson down pat when they had Sachs designing their engine parameters, just ask all the guys who own 166s...

 

[wigglesworth]

Longer stroke usually means more torque. It would be a grunter.

:agree2: It's like using a longer wrench on a bolt. Leverage = Torque.

 

[Busmech]

Mike, didn't your brother try this three or four years ago, I remember him talking about how easy it was to fit the 3120 crank to the 2100 cases. Mike

 

[Wildman1024]

:agree2: It's like using a longer wrench on a bolt. Leverage = Torque.

:agree2: This should be a really good runner...RPM's and peak HP are not everything. You could always bump up to a larger sprocket to compensate for some of the chain speed loss if you lost some RPM.

 

[BIGBORE577]

Dolmar had the long stroke lesson down pat when they had Sachs designing their engine parameters, just ask all the guys who own 166s...

Perhaps, I have both but don't find the 166 to be anything magic. While I'm not a husky fan boy I believe the 2100 series is awesome. Extrapolating the figures, I thought the combo might be awesome. I guess I thought the cross could be the best of both.

 

[leeha]

Nice project.
Although it's only a 5cc increase, I bet
you will notice a difference in larger wood.
Lets see a video.



Lee

 

[Thorcw]

Now curious here did you do this out of necessity to get a saw running with no availibility of the original parts?