Has anyone used the stock distributor reluctor and vr for their MSnS setup or is the resolution too large @ 3 per crank revolution? Maybe a custom drop in 12 point reluctor? The trigger wheel doesnt seem to be the easiest thing to fab along with its pickup bracket and 1mm clearance. Thanks

There's plenty of people that have used stock vr or points style distributors with megasquirt. The problem isn't the tooth count - its dealing with the noise. Since these are very low current signals the megasquirt has to be set to higher sensitivity, which means its more likely to pickup random noise as well. It's best you use a 7 pin GM hei module - this will let the megasquirt do the timing at the same time act as a filter.

I initially had mine running on a 7 pin HEI module and a Lean Burn distributor, worked fine, but I put a crank trigger on there because I was thinking of going distributorless.

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"Mad Scientist" Matt Cramer
'66 Dart - turbocharged 225
My blog - Mad Scientist Matt's Lair

What about the Mopar ECU (orange box) as the VR amp? then just use the coil out as the MS standqard dist trigger? Cheap and a plug in, or does it "pull timing out" at high RPM's?

The mopar box takes input from the distributor and fires the coil. You can use the coil firing signal to the MS, but that means fuel only no timing control. The 7 pin HEI module takes a secondary input from the MS to actually dictate timing. The mopar box is more like the 4 pin hei module.

Ok i might understand. Thought the ms would do timing and drive the coil and use the mopar 4 pin ecu as the vr processor only. Maybe 7 pin would be better as i could mount it down by the distributor. Just wanted to keep it simple with the stock mopar parts. The 7 pin actually alters timing itself, or does it take commands from the ms? How do you set the spark map through the 7 pin? Ideally i just wanted to use the 4 pin ecu as the vr conditioner and not have to make a conditioner circuit inside the ms v2.2 if possible.

Matt, what wheel did you end up with? Was it hard to mount concentrically on the crank pulley? That may be my plan now.

Wiring in a hei module is no more or less complicated then wiring in a mopar box. Anecdotal evidence points to HEI being more reliable and it's physically smaller.

The 4 pin HEI module relies on the distributor mechanical / vacuum advance. The 7 pin HEI module relies on the computer controlling it to set the advance. You'd set the advance by using your pc to interface to the megasquirt, just as you would to alter fuel or any one of the other characteristics you can tweak. If you do this, you'll have to remove any advance mechanism in the distributor to lock it out. Or you can use a later model "lean burn" electronic distributor where that's already done for you.

I mounted a ford 36-1 wheel on my crank. It's going to take machining, there's no easy way. You'll have to mount a sensor too. If you got power steering (pulley in front of the damper) it'll get trickier yet as you won't have a flatter surface to work with. Random note - the face of the damper is approximately 1/16" further back then the face of the outer ring pulley groove.

Got it, thats what I thought but didnt know the MS told the 7 pin to adjust the timing, thought it was all "in house" and the ignition module was just a "dumb" device. Cool. Ill keep my options open, wheel or HEI pumped dizzy.

Used an 8 1/4" wheel and a step bit to keep it concentric.

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"Mad Scientist" Matt Cramer
'66 Dart - turbocharged 225
My blog - Mad Scientist Matt's Lair

This is my understanding:
1. The distributor vr produces a sine wave that is "seen" by the HEI.
2. The HEI changes this signal to a digital one ond feeds this to the MS ECU as a digital signal.
3. The ECU determines the timing of the ignition signal and sends this back to the HEI.
4. The HEI fires the coil or ignition box such as MSD.

All of this is in sequence over and over. The timing is established by the previous ignition event.

Hope this helps.

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You got it.

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"Mad Scientist" Matt Cramer
'66 Dart - turbocharged 225
My blog - Mad Scientist Matt's Lair

Forget it, im going edis. Getting my wheel sunday from the shop. Itll be...trick. will post pics.

I'm eager to see it.

Sam

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Its over on another post too. Nay sayers poo-poo the fact that the teeth are on the rubber side of the balancer, I say "damn the rubber, full throttle ahead!"