Distributor for dual plug head.

I do as run one , 80.s nissen , pos have a spare , two models , points or electronic , hard to find out here in NZ ,
 
Except for reliability there is no need for dual plugs in a normal flathead Model A. The turbulence is good enough so that the flame burns quickly. An engine with overhead valves would benefit. Or a large T head engine.
 
I have a distributor set-up that I think is pretty cool in that it uses an Early V8 Ford distributor mounted onto a Model-B distributer housing. An E. V8 distributor is basically a dual-ignition 4 cylinder distributor. If I recall correctly, the Nissan Distributor is set up for a leading/trailing timing application, -and if so, some of the performance advantage is lost.
 
BRENT in 10-uh-C said:
I have a distributor set-up that I think is pretty cool in that it uses an Early V8 Ford distributor mounted onto a Model-B distributer housing. An E. V8 distributor is basically a dual-ignition 4 cylinder distributor.
Click to expand...

Would love to see some pictures of that.
 
nkaminar said:
Except for reliability there is no need for dual plugs in a normal flathead Model A. The turbulence is good enough so that the flame burns quickly. An engine with overhead valves would benefit. Or a large T head engine.
Click to expand...

My head is an OHV Dual Plug head.
 
The divers helmet type distributor has a cap for each side with a spindle type rotor that feeds both caps. They used one set of points to break the induction circuit and the other set of points closes early to increase dwell time for the coil. There have been several dual coil type aftermarket distributors that were made for performance on V8 engines and I've seen several dual fire set ups made from V8 and V12 type distributors. It has been done for bangers I'm sure but they were rare and parts can be unobtanium for some.
 
The Nissan twin-fire unit I'm running on my BB RAJO fires the exhaust 4 degrees after the intake fires, I believe. I have my fuel pump wired into the intake side of my switch and when all 8 are firing, when I "clip" the exhaust plugs, you can very much hear the RPM drop !
 

Attachments

  • twin ignition switch .jpg
    twin ignition switch .jpg
    50.6 KB · Views: 21
  • Racer dash .jpg
    Racer dash .jpg
    60.5 KB · Views: 17
I do not believe that this is the correct distributor for this dual plug head (Made in France):

568588


Brad in Maryland
 

Attachments

  • P1020405.jpg
    P1020405.jpg
    63.8 KB · Views: 134
The RAJO head that Stevests talked about in Post #12 will benefit from dual plugs because of lower turbulence in an overhead valve head.

The head that Brad showed in Post #14 is a gimmick. The extra plugs will do very little if anything to improve combustion. I would use the plugs that are over the intake valves, where the air/fuel is fresher, and just keep the other 4 plugs in there to plug up the holes.
 
Last edited:
Chris,
cartridge fire is where the sparkplug is removed directly from the chamber with a small sub chamber.
McDowell, Cook etc are this way.
Over the years these heads get changed by drilling out the port or moving the plug directly to the chamber.

As someone did mention before, a single plug more than adequate to ignite the fire in the model A
We have been turning 7200 rpm in the race car on a single plug without a mag

There are many opinions about plug location in the chamber but the reality is that the ex valve opens first and if the flame front starts there it may not make it completely to the opposite side. Take a look at the Brierly head and plug location, it makes a lot of sense.
John
 
johnneilson said:
Chris,
cartridge fire is where the sparkplug is removed directly from the chamber with a small sub chamber.
McDowell, Cook etc are this way.
Over the years these heads get changed by drilling out the port or moving the plug directly to the chamber.

As someone did mention before, a single plug more than adequate to ignite the fire in the model A
We have been turning 7200 rpm in the race car on a single plug without a mag

There are many opinions about plug location in the chamber but the reality is that the ex valve opens first and if the flame front starts there it may not make it completely to the opposite side. Take a look at the Brierly head and plug location, it makes a lot of sense.
John
Click to expand...

The Brierly head is not OHV as mine is. There is one plug on each side of the cylinder. This car sat in the same spot for over 75 years. During that time the original Delco 5195 Two Cap distributor disappeared. I am just trying to get it back on the road.
What you call a cartridge fire I have always heard called a pre combustion chamber.
 
Chris
Yes correct Brierley’s cyl head is not OHV
Plug placement in an OHV is typically not an option with everything

So what is the head?
If just trying to get it running after 75 years a single plug should be adequate

J
 
You must log in or register to reply here.
Back
Top