Sensor Question

[Bernd Felsche]

Peter Gargano tapped away at the keyboard with:

> Bernd Felsche wrote:
> > You mean the starter drive teeth on the flywheel for timing?
> > 
> > Even the manufacturers don't stoop that low.

> If you have a starter that engages the ring gear on one side
> (as per normal), and you're prepared to offset a reluctor pickup
> away from the wearing section of the ring gear, the major problem
> I see is picking up magnetic grunge from the bellhousing. In many
> respects, it's a better option than an optic setup on a converted
> distributor (BTDT).

There are 8 edges for timing in a 4-cylinder engine using a
hall-effect pickup in a distributor. They are accurately-machined.

Flywheel teeth are not made very accurately. They are designed for a
very low duty cycle and life. Starter-engagement problems can cause
some teeth to be damaged, resulting in a "jitter" if you're reading
the teeth. Both faces of an involute gear are subject to wear,
The timing will require some averaging. i.e. you can work around the
foresee-able problems with extra effort elsewhere.

> Having said that, I'm planning on a Hall pickup on the crankshaft
> toothed belt drive pulley for the camshafts of an AlfaSud (flat 4)
> I just need to take a small segment out of one of the 20 teeth to
> make a 20-1 "wheel".

Or drill a small hole into the edge or notch the inside rim so you
don't have to "miss" a tooth! 

At least the drive pulley teeth don't get significant wear. Having
the sensor ripped up if the timing belt snaps would be the least of
your problems.

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