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Cam phasing


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Has anyone thought about making an advance/retard mechanism for the spitfire/gt6 camshaft?

Came up with this:

timing.jpg

An  pair of wheels/gears that can slide from side to side thereby advancing and retarding the camshaft.

My guess is that shouldn't be to hard to make.

Need to enlarge the cover of course, and find a way of actuating it.

Megasquirt/Adaptronic to steer it.

 

Thoughts?

 

Cheers,

 

F.

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You're talking about the very common "phase variator".  We used to have them all over the place in my past life.  It's way too early in the morning for my brain to be working yet but as I recall they just changed the effective distance between the two sprockets.  Interesting idea for a dyno day! ;)

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Interesting idea.  Might be able to get a reasonable amount of swing if you use a long timing chain.  Andy does have a point about this being less benefit that adjusting inlet only but that doesn't mean it's useless (especially if a cam is ground to take advantage of the effect) and we have to stick with the possible for now at least  :)

 

Nick

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Sorry for the late response, was out yesterday.

 

Would you be able to measure this effect tho' and is it not more effective if you only play with the inlet advance, which I defy you to retro engineer

I have read somewhere a manufacturer uses a 2 camshafts, one hollow  so the other can rotate in it.

dodge-viper-camincam.jpg

Found it; Dodge Viper employs this.

http://www.sae.org/automag/technewsletter/070402Powertrain/04.htm

Would be to expensive to make for a Triumph, I guess.

 

John, like others mentioned not a big amount of space to make that fit.

Looks to big to me. :-/

I wanted to link the two extra gears so like on your idea one gear tightens as the other loosens, keeping lash constant.

 

Found one of those merc phasers on ebay, not overly expensive, but you're right maybe better find out how much difference it would really make.

http://cgi.ebay.co.uk/OEM-Mercedes-M119-Engine-Camshaft-Solenoid-A-1190510177_W0QQitemZ110504394419QQcmdZViewItemQQptZUK_CarsParts_Vehicles_CarParts_SM?hash=item19ba933eb3

 

Cheers,

 

Frederick

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That Porsche setup  is nothing more than a phase variator.  Lengthens one chain whilst shortening the other side.  Unless it was active, that's a whole new can of worms.

 

I've been doodling Fredericks idea and I see it's entirely doable.  Probably not in the original cam cover but if incorporated with the belt drive I've been noodling on FOREVER it could be done.  Just the thing to make the project take longer....

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Just the thing to make the project take longer....

Sorry :P

 

Unless it was active, that's a whole new can of worms.

What do you mean unless it was active?

That it changes the timing with rpm?

That it did and that was what I was contemplating, otherwise a vernier gear would be much easier.

Belt drive would make it easier to incorporate, but a lot more work I think, and not so easy to DIY. (at least for me)

If you're going to all that trouble you might as well go OHC. ;)

 

Cheers,

 

Frederick

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Just the thing to make the project take longer....

Sorry, Steve :P

 

Unless it was active, that's a whole new can of worms.

What do you mean unless it was active?

That it changes the timing with rpm?

That it did and that was what I was contemplating, otherwise a vernier gear would be much easier.

Belt drive would make it easier to incorporate, but a lot more work I think, and not so easy to DIY. (at least for me)

If you're going to all that trouble you might as well go OHC. ;)

 

Cheers,

 

Frederick

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Sorry, Steve :P

 

 

What do you mean unless it was active?

That it changes the timing with rpm?

That it did and that was what I was contemplating, otherwise a vernier gear would be much easier.

Belt drive would make it easier to incorporate, but a lot more work I think, and not so easy to DIY. (at least for me)

If you're going to all that trouble you might as well go OHC. ;)

 

Cheers,

 

Frederick

 

 

 

I did not think of changing the phasing with RPM!  Cute.  That's a whole new set of doodles ;D

 

I was pondering it being externally adjustable for dyno testing.  

 

On the Jag sites there's a fellow who's building a variable cam setup for his E-Type like the Hondas do.  I'll bet it's finished by now...

 

Here's the link, it's not quite what I thought...http://www.jcna.com/library/tech/tech0016.html

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