I was going to say that I was assuming the "wobble" would be chiefly radial,
but thinking about it, the type and axis of "wobble" is probaby going to be
random compared to the location of the pickup. With the optical trigger,
however, movement in at least 2 of the 3 dimensions is not a factor., and
even in the 3rd dimension dwell is more or less fixed. Movement in 2 of the
dimensions is a much greater factor in a point system, since it affects the
gap directly, and thus dwell as well as timing. I agree it would also be a
factor with the magnetic pickups, and apparently it is, according to
Kelvin's report.
Anyway, I'm not just spouting an armchair opinion here. I installed the
optical trigger on a very wobbly 25D (actually had a bent shaft, it turned
out) and it improved running significantly. I am still running the system on
a much better but still well-used distributor.
It can't be denied that points work fine, if you want to spend the time
maintaining them; but on the other hand, it would be silly to insist that
they are the be-all and end-all of ignition systems.
--
Max Heim
'66 MGB GHN3L76149
If you're near Mountain View, CA,
it's the primer red one with chrome wires
n 1/7/06 3:24 AM, Paul Hunt at paul.hunt1@blueyonder.co.uk wrote:
> But wobbling a radial slot from side to side across an optical (at least)
> sensor will surely cause the timing to trigger, and so a varying wobble in
> use will cause varying timing? Wobbling a radial slot closer to and further
> away from the sensor will have no affect I agree, which *does* differ from
> mechanical points. Unless they have very effective shields either side of
> the nominal trigger points I'd expect magnetic pickups to have much the same
> sensitivity to wobble as points.
>
> PaulH.
>
> ----- Original Message -----
>> ... since they are sensing a slot (say that 3 times
>> fast), so side-to-side play has no effect on timing.
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