I "think" I have this figured out based on everyones help. Please correct
me if I am wrong.
I think the aligning of the engine at TDC or some value before TDC will have
no effect really except to allow easier intial startup before the actual
timing.
Since no matter where the crank pulley is (TDC or BTDC), the dizzy is
turned so the rotor is aligned with #1 electrode to phase the electronic
trigger. So in my mind at least, the important part is having the elec
ignition in phase (Bill L was emphasising this) which is done by the rotor
aligning with the plug wire and correct adjustment of the optical trigger.
The shutter is mounted on the dizzy cam so any amount of timing cranked in
will still have the shutter and rotor in the same position relative to one
another and firing directly at the #1 electrode. The trigger of course is
mounted on the breaker plate and moves with the cap while doing dynamic
timing adjustments.
So while advancing or retarding the timing will affect where the crank is
located when firing, the alignment of the rotor will still be directly at
the electrode in the cap.
Clear as mud right? Please let me know if my logic is faulty.
Phil Nase
http://home.comcast.net/~philnasecpa
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From: owner-spridgets@autox.team.net [mailto:owner-spridgets@autox.team.net]
On Behalf Of Frenken, Eric
Sent: Thursday, July 27, 2006 11:13 AM
Subject: AW: Static timing and electronic ign
To my understanding of the working principles of a distributor you're
dead-on.
Eric Heinsberg/Germany
www.brits-n-pieces.com
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I just drew a picture of a distributor and a rotor. If you align them both
at TDC, with the window just reaching the photo eye (or the points just
opening) then any amount of advance, from 7 degrees through 35, will move
the rotor end further away from the plug wire outlet thing.
But if you have them aligned when the crank is at 7 degrees BTDC, the
distance between the rotor tip and wire outlet won't be as far as when
aligned at TDC. The shorter path is then achieved by doing the initial
alignment at 7 degrees BTDC rather than at TDC. And even a more direct path
at operating speeds, where it matters more, by doing the alignment at either
a greater BTDC setting.
If I'm missing something here, let me know. I have a Crane unit sitting on
the shelf awaiting installation.
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