> Is there a formula to turn a physical gap opening into a 'dwell' ? Maybe I'm
> just being real stupid about this, but....... The gap is published but I've
> never seen a report of the 'dwell' for a TR 3. Any help out there.
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You know, I've never seen a formula but I would think there is one. Dwell
(a programmed time delay of variable duration.) is just an electronic
measurement of the time the points remain closed (open?) I can't remember
which, but I would think that a car with the same point gap would have the
same dwell - Don't quote me on that.
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> Also I've seen discussion of static timing as opposed to using a timing
> light. I'm sure I read one time that a light should 'not' be used. Any
> comments here?
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I don't know why you wouldn't use a timing light. It's the only _accurate_
way of telling what the heck is going on. The very fact that your timing
light mark was jumping all over the place would indicate either a very worn
dist. (you've said that has been replaced with new) or a worn timing chain.
I can see no reason not to use a timing light to set the timing to
manufacturers spec's. There are other instances where you might not use it
( as stated in earlier post's) but for initial setting's I will always use a
timing light. As far as the vernier, you can look at the breaker plate with
the cap off and see if it rotates when you turn the vernier -
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> to line up the hole in the pulley with TDC. When I installed the OD last
> year I lined up the scribe mark on the flywheel for TDC, then filed a notch
> on the pulley to mark TDC for timing purposes. Anyone see a flaw in this ?
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Hummmm, well no, not if your truly at TDC - -
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> How does one tell what a 'degree' translates into in terms of a linear
> measurement on the pulley. How far from the TDC mark, in MM say, is 10
> degrees BTDC ?
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Simple math, take the circumference of the pulley where the mark will be (2x
pi xr) divide by 360 (degrees) and multiply by how many degrees you want.
Example: a 4 inch diameter pulley with a circumference of 12.566 inches
(319.186 mm), divided by 360 = .035 inch/degree ( 0.887 mm/degree ), times
10 = .35 inches ( 8.866 mm ) for 10 degrees.
Whew, and I thought timing was easy . . .<G>
Barry Schwartz
Bschwartz@encad.com (San Diego)
72-V6 Spitfire (daily driver)
70 GT6+ (when I don't drive the Spit)
70 Spitfire (project on hold for now)
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