Dizzy and crankfire combo for twin plugs

kenikh · 10-19-2008, 07:18 AM

Can you drive ignition to stock distributor off of a crankfire system like a TEC1, HPX or HPV1? My interest is in using the stock dizzy to drive the top plugs and a coilpack to drive the bottom set of plugs on a twin plug motor. You could clearly do this with the two systems (dizzy and crankfire) tuned in isolation, but really would like them to leverage the same curve/ignition data source.

Grady mentioned something like this a few years ago, but the details elude me.

Steve@Rennsport · 10-19-2008, 12:02 PM

Well,...one would need a trigger wheel and sensor to drive any Electromotive product and that requires either a bolt-on wheel or special lower pully such as the Clewett ones.

The stock distributor will not fire any of these units so you are faced with building a hybrid ignition setup that will be rather challenging to tune well.

If I recall, Grady's system used a separate distributor, modified to be driven off the left camshaft drive. Not easy to time, either.

FWIW., I do have some better ideas but none of them are what people would characterize as inexpensive,....

kenikh · 10-19-2008, 12:31 PM

The solution I recall is using the stock dizzy and a crankfire computer to do what Motronic does: use the toothed wheel for the computer/curve and use a dizzy as a dumb spark distributor. You then add a coil pack for the plugs not driven from the dizzy. This solution would give a twin plug option that looks stock and drives the plugs from one curve/advance source. As you can probably tell, cheap is my goal.

You can find a single plug HPV1 for under $500.

Steve@Rennsport · 10-19-2008, 12:35 PM

Quote:

Originally Posted by kenikh

As you can probably tell, cheap is my goal.

You can find a single plug HPV1 for under $500.

Noble goal indeed, but it cannot be done well for "cheap,...

Henry Schmidt · Henry Schmidt's Garage

Here's another option.
Use a distributor to send a signal to a signal MSD box. Use the MSD to trigger two coils. The two coils to send a spark to the stock dist. and the cam driven dist.
The cam driven distributor will need to be fabricated but the cost would be minimal.

Here is a cam driven distributor that was used on a version of the 930 . It incorporated both distributor and turbo scavenge pump.
It could be design sans oil pump.

jcge · 10-19-2008, 01:37 PM

Interesting setup Henry - do you have a Bosch part number for the screw down 6 plug distributor cap ??

I thought I'd seen this posted previously as 962 ?? (or 956 ?)

Regards,
John

kenikh · 10-19-2008, 01:59 PM

My basic question still stands unaswered: If a 3.2/3.6 Motronic can use a toothed wheel (albeit off of the flywheel) and computer with a distributor to send spark, why can't an aftermarket crankfire system be used to do the same?

Steve@Rennsport · 10-20-2008, 08:27 AM

Quote:

Originally Posted by kenikh

My basic question still stands unaswered: If a 3.2/3.6 Motronic can use a toothed wheel (albeit off of the flywheel) and computer with a distributor to send spark, why can't an aftermarket crankfire system be used to do the same?

You can, but not using Electromotive hardware,....

kenikh · 10-20-2008, 08:28 AM

Quote:

Originally Posted by Steve@Rennsport

You can, but not using Electromotive hardware,....

So big bucks systems like Motec only, then...got it.

jcge · 10-20-2008, 01:10 PM

Quote:

Originally Posted by jcge

I thought I'd seen this posted previously as 962

Henry Schmidt · Henry Schmidt's Garage

Quote:

Originally Posted by jcge

Interesting setup Henry - do you have a Bosch part number for the screw down 6 plug distributor cap ??

I thought I'd seen this posted previously as 962 ?? (or 956 ?)

Regards,
John

Same concept different part.