Creating Inductive Pulse

shortbus

Joined Sep 30, 2009
10,045
You mentioned "12 plug distributors" so you've probably seen these, http://www.raceservice4u.com/Twin plug.htm Just buy the cap and rotor and make an adapter ring so it would fit your distributor.

You are aware that unless you have a true hemispherical combustion chamber and piston top, like the old Harley engines used, or a cylinder of ~5" diameter, there is no real advantage to dual plugs. With a flat top piston and small, ~4" diameter, any difference in time of ignition start will probably increase the chance of pinging/detonation from flame fronts colliding. For some reason you don't want to share the make of engine your working on, so there is a lot of guessing going on in the answers. Better combustion chamber shape works much better than dual plugs for most engines.
 

shortbus

Joined Sep 30, 2009
10,045
The dual plugs can be fired using a dual output coil.
But that does not apply to that that modification. A distributor using that module still fires only one coil and uses the rotor and cap to discriminate between cylinders. Using that module and wiring it to six coils they would all fire in unison. He needs them to fire separately, one cylinder at a time in the correct firing order.
 

crutschow

Joined Mar 14, 2008
34,285
But that does not apply to that that modification. A distributor using that module still fires only one coil and uses the rotor and cap to discriminate between cylinders. Using that module and wiring it to six coils they would all fire in unison. He needs them to fire separately, one cylinder at a time in the correct firing order.
My understanding is that the conversion adds components to the inside of the distributor that generates signals to fire an ignition module for each cylinder. Thus the spark does not go through the distributor.
 

shortbus

Joined Sep 30, 2009
10,045
Nope, he just converts a points or other brand distributor to use the GM HEI module. Probably adds a reluctor ring to the points cam or machines the shaft for a reluctor ring. Then machines the base of the distributor to fit the HEI module.. There's another company that started this conversion years ago, cal Davis Unified Ignition. Many have copied what they started.

Here's a quote from the link you provided that explains what they do -
"The objective is simple, build a dedicated General Motors type true High Energy Ignition (HEI), in either regular mechanical/vacuum advance curve style HEI, or, for Electronic Fuel Injection Feedback HEI (such as the Holley Commander 950 series, and other OEM and after market fuel injection systems). Or, a dedicated MSD magnetic pickup trigger-only system, into stock points distributors for American car engines.

My conversion ignition systems are designed around electronic components that are readily available from any good auto parts store. There are no special or unobtainable electronics or other parts used in any of my conversion ignition systems."
 

Thread Starter

cag2014

Joined May 15, 2016
9
Shortbus - yes, assume a 'boxster' design. Cylinders are 100mm dia. Pistons are what they are, high dome, 9.5:1. Heads are hemi.
However, we are not redesigning the mechanical aspects of the motor, we know what the motor has done in the past.
We just need to fire off the 2nd set of plugs.
Again, there existing methods (systems) to do this, working with a crank sensor either at the pulley or flywheel, however expensive.
 

shortbus

Joined Sep 30, 2009
10,045
Again, there existing methods (systems) to do this, working with a crank sensor either at the pulley or flywheel, however expensive.
Only if you buy the whole system. The trigger wheel and pickup mount are pretty straight forward fabrication problems. An MSD or similar box is a little pricey but still pretty affordable.

I'm a six cylinder lover myself. A guy down the road when growing up built and raced a gasser(drag race class) when I was a teenager. Ran a 1950 Ford coupe with a GMC 302CI engine. Had a Wayne 12 port head and the whole works, this was in the middle to late 1960's.

I built a Jeep with a Chevy 292 truck motor, with headers and a fabricated sheet metal intake manifold and 4 bbl Holley carb.
 
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