triggering an HEI module

[Bob Wooten]

If triggering is the issue maybe an Ignitor like the pertronix is the way 
to go (www.pertronix.com ) or possibly a 
Hall effect like MSD's.

 

BW


----- Original Message ----- 

From:  

To: gmecm at diy-efi.org 

Sent: 3/8/01 11:59:23 AM 

Subject: triggering an HEI module





Hi,

Has anyone tried to determine what type of signals will trigger an HEI 
module?

To be more specific with what I want to achieve:

I have a little foreign four banger with a really pitiful points 
ignition.  I 

was thinking of converting it to GM DIS as a first step towards full-blown 


GM-EFI.

The problem is that the only after-market conversions from points available 


for this car are to 'optical sensor' ignition, which will result in a 
square 

wave signal from 0v to 12v.  I know HEI modules (and DIS) are 
looking for a 

sine wave.

Does anyone know if a square wave will trigger the module?

Even MORE specific:

my idea is this: Crane makes a unit (the XR-700) that is 
optical.  Their 

generic kit comes with a bunch of 'shutter wheels, including one for a 
v12.  

That's 12 slots.  Add two slots in the appropriate places (with 
an 

exacto-knife), and you have the correct pattern to fire a DIS unit (4cyl or 


6cyl... they require the same timing sequence.) (the GM DIS needs 6 equally 


spaced trigger signals, plus one 10' after TDC, per crank rev.) (you would 


double that if you were to plane on running it off of the distributor, as I 


am.)  And for the time being, I would just keep the mechanical 
distributor 

advance, which would send that advanced signal to the DIS unit, thus 
keeping 

my stock timing.  Pretty neat, huh?

which leads to my second question.....

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--- Bob Wooten

--- r71chevy at earthlink.net 

--- www.r71camaro.homestead.com 

 
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