flywheel teeth counting (Re: measuring hall output)

[auditude at neta.com]

Hello everyone,

[The subject is an '88 5kcstq motor, and the goal is to measure the
hall sensor output window using a DMM, hand turning the motor,
and using the flywheel teeth to calculate crank position in degrees.]

I counted the teeth between the timing reference pin, and the zero
("0") stamped on the flywheel.  I fully expected the number of teeth
to come out to 62btdc, which is where that pin supposedly is..

I counted the teeth between the timing reference pin, to the "0"
stamped on the flywheel, and I come up with 35 teeth.  (yesterday
it counted 36, but today I counted the 200tq one, which is off the
car and got 35.)

If that pin is at 62btdc, then how come I can't come up with any
math that will make 35 teeth equal 62 degrees?  Is the zero
stamping not TDC?

I thought that if there were 135 teeth in 360 degrees, then each
tooth is 2.667~ degrees, so 35 teeth would be 93.1 degrees, not 62.

I think I'm missing something conceptual here.  Does anyone know
what it is?

Thanks,

Ken

On 22 Feb 2002, at 15:37, Orin Eman wrote:
<snip>
> There is no need for
> anything fancy to place the mark - each flywheel tooth is 2.7 degrees.
> Count teeth from the zero and interpolate as necessary.