i know its best that the trigger wheel is slightly bigger diameter than the pulley, but suppose the outer diameter (outside the teeth) was exactly the same as the pulley... would that be ok? i'm thinking with the sensor needing to be so close, the pulley shouldn't affect the sensor?

Presumably it depends on what material the pulley is made out of. If it was made out of a ferrous material it would "mask" the trigger wheel and potentially stop a signal.

You'd also be faced with mounting the sensor at an angle to the teeth of the trigger wheel, which might generate an acceptable signal at low revs, but the current / voltage of the pulses generated at higher revs may not be sufficient to give a constant reading to the EDIS module. I wouldn't consider myself an expert, but I'd be expecting misfires or loss of advance at midrange / high revs if this was an issue.

Hope that helps,

Francis.

Mines about the same diameter,but spaced away from the pulley a little bit and works fine.

I'm guessing you've got a trigger wheel then

Put a 5mm spacer (smaller diameter than teeth on trigger wheel and you'll be fine).
Edit: as ^^^ grrr must type quicker.

If you don't already have a wheel already it's probably easier to buy one than scavenge one and have to experiment to get a good signal (I doubt most people have a scope they can use to set up).

http://trigger-wheels.com/ has lots of useful information an wheels in most sizes

mediabloke: I don't understand, why would the angle of the sensor have to change, surely you'd have to fabricate a bracket to suit anyway so would keep it at 90 degrees.


[Edited on 13/11/08 by iank]

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Originally posted by iank

http://trigger-wheels.com/ has lots of useful information an wheels in most sizes

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i haven't got one yet. saw one on ebay which was for a mini. the hole in the middle was perfect size for my pulley (as the same size as the recess) but the outside was the same diameter as the outside of the pulley. was still about £18 delivered. better than trigger wheels and their £18 plus post.

I'll try martin townsend though

far from locost but I got this made:


http://s5.photobucket.com/albums/y170/mcerd1/Dax/08072008059.jpg
http://s5.photobucket.com/albums/y170/mcerd1/Dax/08072008060.jpg

its an alloy copy of a pinto pulley (cortina type) with a bit extra on the front for the ring type 36-1 (from triggerwheels.com)
he skimmed a little out of the centre of the trigger wheel on the lathe to make it a good fit
its going to get hard anodised soon - you don't want to know what the total cost is though

Nice looking part how thick is the trigger wheel ?

Jason

Its 5mm thick

here's my drawing if anyones interested
(to suit a pinto with a cossie crank = +8mm on the nose length)

I've got it in AutoCAD if anyone needs it

[Edited on 13/11/08 by mcerd1]

Thanks

quote:

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Originally posted by short track 123
Nice looking part

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quote:

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Originally posted by BenB
Presumably it depends on what material the pulley is made out of. If it was made out of a ferrous material it would "mask" the trigger wheel and potentially stop a signal.

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As long as the holes are larger than the tip of the VR sensor it will work correctly. If the hole size is too small, the output of the sensor will be considerably reduced .