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converting a dual coil dual point V8 distributor to hall effect

Roto-Faze

New Member
Hello Im new to this site and Im looking to confer with a automotive ignition engineer. Specifically about the phasing between the two triggers . I already have have 4 magnet ring fitted on the point cam which is a four lobe. All dual coil V8 distributors fire each cylinder at 45 degrees alternately . I have the first trigger mounted at TDC on #1 plug terminal . Im not sure where to set the second trigger. If both are at 45 degrees then both will fire at the same time and I do not think this would work. Some how the second trigger must be set to open the circuit 45 from the first closes?
Any experts in the field have the answer?
 

KeepItSimpleStupid

Well-Known Member
Most Helpful Member
With dual coil, you fire one into the exhaust stoke or the "wasted spark" system and one in the power stroke.

e.g intake, compression, power, exhaust.
 

crutschow

Well-Known Member
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Some how the second trigger must be set to open the circuit 45 from the first closes?
I believe that's true.
The second pickup would need to be at 45 degrees from the first pickup.
Isn't that how the dual points were configured?
 

shortbus=

Well-Known Member
Most Helpful Member
In a dual points ignition, one set of points closes the circuit and the othe opens it, this is done to get more dwell for the coil and to stop erosion of the points/ longer life.

All of that is eliminated when going to a Hall or induction sensor in a points less electronic distributor. So I guess I don't understand what you're doing with this.

 

crutschow

Well-Known Member
Most Helpful Member
In a dual points ignition, one set of points closes the circuit and the othe opens it,
That's true for a standard distributor ignition, but for this dual-coil system the TS says there is a 4 lobe cam, so wouldn't one set of point handle one set of coils, and the other handle the other set at a 45 degree difference, so they can correctly fire all eight cylinders at the 90 degree crankshaft rotation for each cylinder firing (since the cam operates at 1/2 the crankshaft speed)
All of that is eliminated when going to a Hall or induction sensor in a points less electronic distributor. So I guess I don't understand what you're doing with this.
The point is to eliminate the points. :)

.
 

shortbus=

Well-Known Member
Most Helpful Member
That's true for a standard distributor ignition, but for this dual-coil system the TS says there is a 4 lobe cam, so wouldn't one set of point handle one set of coils, and the other handle the other set at a 45 degree difference, so they can correctly fire all eight cylinders at the 90 degree crankshaft rotation for each cylinder firing (since the cam operates at 1/2 the crankshaft speed)
Yeah, your correct, some people just want to make things more complicated than necessary.
 

Roto-Faze

New Member
Excuse me but a couple of you don’t get it . I’m not trying to complicate things I am simply converting from points to magnetic triggers in a extremely rare Jackson Roto Faze dual coil distributor . These were built in limited numbers from 1959 -1961 and are a masterpiece of engineering and aesthetic design. Four lobe point cam with two point triggers and twin opposing caps. An in a beautiful finned cast aluminum body.
The point is I own a nostalgia Drag race Gasser and this distributor is one of the great additions to the engine bay.
With that said all I really want to know is the phasing if the two Pertronix triggers . The # 1 firing trigger is set so what I’m going to do next is approximate the mounting of the opposing second trigger to open the circuit at 45 degrees from the closing of the first trigger using a distributor machine . The second trigger plate I made to be adjustable to calibrate. .
I am confident this will work but any positive input is welcome .
Anyone that still wonders why I am using a vintage piece like this then I suggest to simply do a search Roto Faze dual cap and take a look and you will then understand why I like it and want to continue to run with it.
 

rjenkinsgb

Well-Known Member
Most Helpful Member
Nice piece of gear!
It appears to have two totally independent (electrically) four-cylinder sections, with two ignition coils.

That means the "point" sensor opening should be offset by 45 degrees from one to the other; not closing to opening.
That way the two halves interleave correctly for the eight cylinders.

Each end on its own fires at 90' intervales (or distributor shaft rotation) so 45' provides the equal alternate split to each coil.
 

Roto-Faze

New Member
Yes that’s it . There were a few Dual coil ignitions created in the ‘50’s and early ‘60’s . The Spalding Flamethrower , WC duocoil, and Mallory but the Kong Jackson Roto Faze was the Rolex of all the Dual coil distributors. The Idea was to double the coil saturation with 60 + degrees of dwell time opposed to the 3o+Degrees Found in a conventional 8 lobe single point V8 distributor . Points and coils are working half as hard and point float is virtually eliminated due to the gentile four lobe ramps. 10,000 RMS capability and a huge spark is the hallmark of these ignitions .
The only draw back is point wear that is impossible to cure . The Hall effect magnetic trigger is the key to longevity and perfect timing virtually forever.
 

Roto-Faze

New Member
Yes I already have it . It may be from a ‘45-‘55 Willy’s Jeep as are tha caps and rotors but I never cross referenced the part number from Pertronix.
Those war veterans turned Hot Rodders were smart guys and many of them used war surplus parts that were abundant in the late‘40’s-the ‘50’s and dirt cheap by the pallet full.
I made mounting plates from water jet cut steel plate and mounted the primary trigger to the plate using industrial silicone adhesive. That stuff is heat and flame proof and is flexible not brittle to prevent fatigue from vibration. It is indexed at the No. 1 cylinder rotor position . The opposing secondary trigger is mounted approximately At 44 degrees and is adjustable to advance or retard to set the 45 degree phasing once its on the Distributor machine . I’m confident this will provide dependable and ultra accurate phasing for maximum power.
I may have no doubt been losing power with the points due to wear but with 550 HP its only noticible in MPH at the strip.
 

Roto-Faze

New Member
In a dual points ignition, one set of points closes the circuit and the othe opens it, this is done to get more dwell for the coil and to stop erosion of the points/ longer life.

All of that is eliminated when going to a Hall or induction sensor in a points less electronic distributor. So I guess I don't understand what you're doing with this.

This piece is a separate circuit twin 4 cyl. Distributor combined in one cast case with two 4 cyl. Caps built for V8 applications . Two coils fire alternately with twice the coil saturation and spark. With the points high rpm float is well beyond 10,000 RPM due to the 4 lobe cam . I’m simply eliminating the mechanical point switch’s and replacing them with two magnetic triggers for reliable long life and consistent tune.
 

shortbus=

Well-Known Member
Most Helpful Member
This piece is a separate circuit twin 4 cyl. Distributor combined in one cast case with two 4 cyl. Caps built for V8 applications . Two coils fire alternately with twice the coil saturation and spark. With the points high rpm float is well beyond 10,000 RPM due to the 4 lobe cam . I’m simply eliminating the mechanical point switch’s and replacing them with two magnetic triggers for reliable long life and consistent tune.
You didn't state in the begining what you were doing. The Roto-Phase wouldn't work long on the street though, the long dwell would be very hard on coils in everyday driving.
 

Roto-Faze

New Member
Hello short bus . Actually there will be no problem . Keep in mind that any 4 cylinder ignition weather it’s points or electronic has twice the dwell and coil saturation and they do not burn out coils . Its all in the coil resistance . 4 cylinders require minimum of 3-4 ohms of resistance and 6 - 8 cylinders require less . This I have just learned by searching and reading Pertronix instructions and troubleshooting guide.
I have run this set up with the points for nearly 9 years with a pair vintage Judson coils with no problems . And that is with the recommended Dwell of 60 degrees.
I will agree with you that on a typical V8 with 8 lobe cam it would be hard on coils , points and condensers running 60 degrees dwell and especially if there No ballast resistor or the wrong coil resistance.
 

shortbus=

Well-Known Member
Most Helpful Member
I have a Judson coil that I had on an old hill cimbing Jeep I built years and years ago. It didn't like being on a 4 cylinder and burned out. Still have it somewhere in my junk.
 

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