The Making of a Full Circle Crank in a Homeshop

[Sty57]

Wouldn't you be losing case volume with the ring on?
Or do you gain velocity to overcome the weight difference?

 

[jmssaws]

Filling the crankcase makes velocity,kind of like a super charger for a 2 stroke.
In layman's terms.

 

[Jimmy in NC]

I think its all about reducing case volume and increasing transfer velocity?

 

[tree monkey]

to decrease case volume. increase peak rpm

 

[jmssaws]

Weight is marginal and overcome by velocity.

I'm gonna do serious testing in a 660 when my crank arrives, we will all find out what one will do for a muffler no head saw.

 

[Jimmy in NC]

Raising RPM does it lower the torque? Or does it raise the peak torque RPM?

 

[jmssaws]

If we're gaining rpm with a heavier crankshaft I would lean towards a increase in tourqe.

 

[Sty57]

So this is a lot like a turbo crank? I can remember on wheelers and sleds guys were doing stuff like that.
I just never knew why.

 

[Sty57]

 

[idiotwithasaw]

This may be a completely hairbrained idea, but why not turn the lobes all the way down then use a peice of appropriate thickness plate and drill a hole just a few thousandths smaller than what you turned the crank down to then machine it to the desired diameter then use an end mill or a cnc to cut some voids to provide the counter balance. Then heat up the plates and line them up and slip them on like a bearing or press fit them, this would be the trickypart getting them even. then put it back in the lathe and turn them down even.
You would need a scale to make sure they were the same weight and it would be work, but would it be more durable than jbweld?

 

[idiotwithasaw]

Make it out of AR plate, never have to worry about it again.

 

[Jimmy in NC]

I thought the factory stuffer are just plastic that snaps on. Im fairly certain JB will work.

 

[jmssaws]

People doubt jb weld but it's some pretty amazing stuff.

 

[Deets066]

This may be a completely hairbrained idea, but why not turn the lobes all the way down then use a peice of appropriate thickness plate and drill a hole just a few thousandths smaller than what you turned the crank down to then machine it to the desired diameter then use an end mill or a cnc to cut some voids to provide the counter balance. Then heat up the plates and line them up and slip them on like a bearing or press fit them, this would be the trickypart getting them even. then put it back in the lathe and turn them down even.
You would need a scale to make sure they were the same weight and it would be work, but would it be more durable than jbweld?

Too heavy, lots of weight unless it was titanium or aluminum

 

[Deets066]

Full titanium full circle crank and rod!

 

[Mastermind]

I was using Devcon, but went back to JB Weld.....

It's just much easier to use.

 

[idiotwithasaw]

Wonder if aluminum would be heavy enough to act as a counter balance. I still think that a lobe turned from one peice of metal will be a lot stronger than jbweld and a metal ring. Just think if the jb weld had an air pocket and chipped the damage it could do to a top end, be like a bearing going out.

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[Deets066]

I was using Devcon, but went back to JB Weld.....

It's just much easier to use.

And cheaper

 

[tree monkey]

or just make a whole new crank

 

[idiotwithasaw]

That's almost exactly what I had in my head

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