Scaled up 2X Demon camshaft

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bruski

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Howdy everybody,
I purchased Steve's Demon drawings a while back and have decided to maybe build a scaled up 2X version of it. While scaling up the camshaft drawings, I am a bit confused on what to scale up and what to leave the same. The lift would scale up from .070 to .140 and leave the duration the same, lobe separation the same the base circle would scale up. My question is what about the flank radius, would it stay the same or should it be scaled up double size?
Thanks for your help,
bruski
 

awake

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Interesting question. Not haveing scaled up or down an engine, am I right in thinking that scaling it 2x will mean that the displacement will actually increase by a factor of 8 (if both the cylinder diameter and the stroke are doubled)?
 

ICEpeter

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Hello Bruski,
Regarding up scaling your Demon Cam lobe, please have a look at a post called "Another cam grinder" and look at # 32 post that gives some idea about how to scale up or down a cam lobe.
Se also the skeetch below which may help in figuring out in your endeavor.

1591392657284.png
 

bruski

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Thanks for the help. The engine will be about 12.3 cubic inches to be exact.

bruski
 

stevehuckss396

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Unless i'm mistaken that sketch shows how to make the follower for a cam grinder. Using the above sketch will yield a double size lobe with the original lift. Just double everything that has to do with the shape of the lobe. Base circle, flank radius, lift, and nose radius. Double everything maintaining the lobe position on the shaft.
 

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