[Gmecm] HEI conversion & cam sync

[Carl Rumberger]

> I wouldn't mind hearing how to set "phase" between the
> rotor and the timing pickup.  Otherwise the rotor may not
> be partially parallel to the desired plug contact for all
> timing conditions.  Of course that can be checked with
> a transparent HEI cap afterwords, but it would be better
> to set it up right before hand.

The phasing can be altered by changing the position of the pick-up coil
relative to the dist. housing. It can also be altered by changing the
position of the "star wheel" to the rotor mounting surface or changing the
position of the cap relative to the dist. housing, though these are more
difficult to do.

With EST the rotor phasing isn't fixed. It should sweep across the cap
terminal with timing change. The rotor phasing should be past the cap
terminal with the most retarded computer timing signal(GM-EST). The rotor
phasing should be before the cap terminal with the most advanced computer
timing signal (by approximately the same amount that it was past when
retarded).

You don' t have to have a see through cap to view this. With a timing light,
note the retarded and advanced timing points. If you know the approx. spark
tables you will be using, you already know these figures (assuming the
timing is properly set). Position the crankshaft(static) at the advanced and
retarded timing points and see where the rotor points relative to the cap
terminal.

> I have been thinking some more about adding cam
> sync to the commonly available & very cheap CCC type
> HEI.  Perhaps just dropping a plug wire through a pickup,
> with a bit of signal processing, would be the easiest.
SNIP

Unless you plan to go sequential EFI or "coil on/near plug" ignition, I
don't see any point in knowing cam position/sync.

Carl Rumberger
Performance Dynamics
perfdyn at cwnet.com