Author Topic: My performance cam gear progress  (Read 2132 times)

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Offline BigMike

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My performance cam gear progress
« on: February 03, 2010, 06:22:06 PM »
Hey Bill,

Kevin's brother-in-law got your cam gear digitalized:



And I've been working on my own version, here is a teaser picture:



I'm designing this one to operate on the intake cam which poses a far greater mechanical challenge.

Mike
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Offline BigMike

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Re: My performance cam gear progress
« Reply #1 on: February 04, 2010, 10:29:58 PM »
Update on my design


Here is the cam gear with the cover installed:


and here is what the counter weight setup looks like:


It is a very simple design and right now it can achieve 10-degrees of positive rotation. So it can be configured to have -5 degrees initially (at low RPMs) and then advance a whopping +10 degrees in the positive direction after a certain RPM is met.

I did some testing with COSMOSMotion but I have no idea how to determine the amount of actual real-world preloading the cam shaft sees at say 4000 RPM considering the 8 valve springs and frictional forces from the oil pressure, the cam journals (I don't know their dimensions), the force applied by the timing belt, the moment of inertia of the camshaft, the forces between cam lobes and shims, etcetera, etcetera, etcetera.

So I have designed it to have about as much mechanical advantage as possible so that I can play with a wide range of spring constants to test it out on the actual engine.

Also, all dimensions are guesses since I don't have a cam gear handy. I am going to pick one up from Bill hopefully soon and I'll get this all properly setup in CAD and then I can just simply email the file to our machinist and I can get some prototypes made.

Mike
-/_/___/__________\___\_\-
|______________________|
|-------\___________/------|
```````````````````````       
R135
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  246

     My 1987 Supercharged 4A-powered 6-speed MR2

Offline Sirdeuce

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Re: My performance cam gear progress
« Reply #2 on: February 11, 2010, 08:04:40 PM »
Can you get the thin to advance, then retard, then advance? Or vice versa.
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