Full Crank vs. Stuffed Crank

[stihlaficionado]

What does stuffing the crank do for a saws performance?

 

[Deets066]

What does that mean?

 

[stihlaficionado]

Holes are drilled in the crank & resin injected. http://www.davesmotors.com/store/product118.html

 

[stihlaficionado]

There are some old posts dating to 2005 & older about a 357 vs. 359 husky & a stuffed crank

 

[Deets066]

Just for reducing weight I'm assuming? When I was building my snowmobile I heard that removing 1 pound of rotating weight is equal to 7 pounds of stationary weight
Sounds like a lot of work for what you might gain in power.

 

[HuskStihl]

Reduces crankcase volume

 

[GrassGuerilla]

opcorn:

 

[RandyMac]

Reed valve McCullochs have stuffers.

 

[sawfun]

I believe I had read that a smaller crankcase volume has a supercharging effect and speeds the mixture flow through the transfers.

 

[blsnelling]

It decreases crankcase volume, thereby increasing transfer velocity.

 

[HuskStihl]

Wait a minute, did you say "stuffers" or "fluffers."

 

[Beer Gut]

I was wondering what else is needed when one stuffs the crank?



Such as port work, carb tuning..

 

[Deets066]

I just now read the link for Dave's motors, makes a little more sense

 

[big t double]

Wait a minute, did you say "stuffers" or "fluffers."

See...

 

[sawfun]

I should think on the engines that dont need to flow through the piston sides, that a flat bottom on the piston would help as well. Also an aluminum rod for racers as it has to have volume to make up for strength loss.

 

[Mastermind]

It decreases crankcase volume, thereby increasing transfer velocity.

Exactly.......and that by itself raises the peak power point, and in some cases narrows the torque curve.

I'm not sold on the "need" for that in the saws we build......as in a working saw. I "think" it may put the working power at a RPM that is unrealistic.

Of course, there is still so much I don't fully understand.

 

[67L36Driver]

Reed valve McCullochs have * stuffers.

*crankcase stuffer.

The bottom end of a two stroke cycle has a 'compression ratio' just like the top end.

 

[sunfish]

Exactly.......and that by itself raises the peak power point, and in some cases narrows the torque curve.

I'm not sold on the "need" for that in the saws we build......as in a working saw. I "think" it may put the working power at a RPM that is unrealistic.

Of course, there is still so much I don't fully understand.

Randy, have you done a 357xp?

The 357 has stuffers, 359 doesn't. The 57 is zippier, but the 59 feels a little torquier...

 

[Mastermind]

That's my take on those two as well Don.

It seems that the stuffed engine accelerates quicker......

 

[old-cat]

That's my take on those two as well Don.

It seems that the stuffed engine accelerates quicker......

How much difference is there in those two cylinders?