Flathead "ELCO TWIN" unit.........distributor
- Thread starter BUBBAS IGNITION
- Start date
BUBBAS IGNITION
Well-known member
Actually it is a casting , you can see the casting lines. I also at first look thought it was square pieces.
I think Bubba knew what to say but did not say it----the dual plug thing is not like having 2 four cylinder systems and it does not allow for cooler coil temperatures, etc. etc. The dual plug system requires 16 "sparks" from 2 eight cylinder systems. I believe the Nash twin 8 distributor was one such example that was used to get the 16 sparks from a single distributor with two coils and 16 wire posts on the cap.
BUBBAS IGNITION
Well-known member
Thanks for the correction , i wasnt very clear on the first post etc.
I spent a little time at the shop today and will have the parts cleaned up tomorrow etc.
The Nash unit is two eight cylinder ignition systems with a dwell adjustment for each set of contacts, the advance is early autolite ( very much like a chrysler cast iron unit) and it also has a sync plate to allow some adjustment to the timing between the two sparks. I think in the past we have adjusted this to fire both at exact same time.
I will dig up some more info on the twin spark later this week. There is a couple cars being produced today using twin plugs per cylinder for various reasons etc as well.
Bubba
John Kennedy
Senior Member
Pretty fascinating stuff there!
BUBBAS IGNITION
Well-known member
Ok guys , got er done today and shipped back to the customer .
Heres what i learned this week end and today.
The Nash six and eight was dual coil with two plugs each cylinder. Nash said in their adds:
For 1929, twin ignition was added to the two OHV engines and all series utilized aluminum pistons. Twin ignition meant there were two spark plugs for each cylinder, two coils as well as two sets of points and 2 condensers in one distributor. Nash claimed the improved combustion resulted in greater horsepower and greater fuel economy. In addition, greater reliability was achieved as the engine could run well even if one side of the ignition system failed. Unit was used until 1936 and maybe after.
(A note: the new Hemi also uses two spark plugs per cylinder, and some modern engines rely on spark plugs with two electrodes. The principle was sensible and ahead of its time.
The pics below show the story in detail.
The spark from each set of eight is set to occur at the same time timing of the spark is determined by the distributor position and distributor cam etc.
I suppose spark timing per plug per cylinder could be tuned if needed by adjusting the contacts and adjusting the sync of each set of points.
The advance ( autolite) is a great little unit and is almost perfect for the flathead setting of 28 degrees at 2500 rpm.
This distributor is very well made and ran on tester at 6000 plus rpm.
Special care must be taken with spark plug gaps ( .025 max) to prevent burning up the cap and rotor system. Timing is crutial and the use of correct resistance ignition coils is also a must do.
I suggest 1.5 ohm coil with 1.5 ohm ballast to keep the current low in the primary system.
Cylinder to cylinder distance (even with large cap) is very small and spark jump over or cross fire is easy. Wiring ( plug wires) must be in very good condition and connections must be good as well.
All in all a very good setup for the flathead !!!!!!
Heres what i learned this week end and today.
The Nash six and eight was dual coil with two plugs each cylinder. Nash said in their adds:
For 1929, twin ignition was added to the two OHV engines and all series utilized aluminum pistons. Twin ignition meant there were two spark plugs for each cylinder, two coils as well as two sets of points and 2 condensers in one distributor. Nash claimed the improved combustion resulted in greater horsepower and greater fuel economy. In addition, greater reliability was achieved as the engine could run well even if one side of the ignition system failed. Unit was used until 1936 and maybe after.
(A note: the new Hemi also uses two spark plugs per cylinder, and some modern engines rely on spark plugs with two electrodes. The principle was sensible and ahead of its time.
The pics below show the story in detail.
The spark from each set of eight is set to occur at the same time timing of the spark is determined by the distributor position and distributor cam etc.
I suppose spark timing per plug per cylinder could be tuned if needed by adjusting the contacts and adjusting the sync of each set of points.
The advance ( autolite) is a great little unit and is almost perfect for the flathead setting of 28 degrees at 2500 rpm.
This distributor is very well made and ran on tester at 6000 plus rpm.
Special care must be taken with spark plug gaps ( .025 max) to prevent burning up the cap and rotor system. Timing is crutial and the use of correct resistance ignition coils is also a must do.
I suggest 1.5 ohm coil with 1.5 ohm ballast to keep the current low in the primary system.
Cylinder to cylinder distance (even with large cap) is very small and spark jump over or cross fire is easy. Wiring ( plug wires) must be in very good condition and connections must be good as well.
All in all a very good setup for the flathead !!!!!!
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BUBBAS IGNITION
Well-known member
a few more .......
A couple more notes , advance unit, contacts and distributor were ultrasonically cleaned. The ultrasonic unit even removes te oxidation from the contact points making them very usable with a light file ..
High ( .40mfds) condensors are used to prevent contact arching.........the best there is ...
A couple more notes , advance unit, contacts and distributor were ultrasonically cleaned. The ultrasonic unit even removes te oxidation from the contact points making them very usable with a light file ..
High ( .40mfds) condensors are used to prevent contact arching.........the best there is ...
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rotorwrench
Well-known member
You mentioned the cross over firing that can occur so I thought I'd add some observations that come from experience with cross firing. I've found that any type of contaminants on the insulated surfaces can cause cross fire to happen. If a person cleans the components of all traces of contamination, it will minimize the tendency for the spark to travel where it's not wanted. Even finger prints in the wrong place can contribute to this. Clean it well then clean it again before plugging everything together and it will definitely help prevent the pesky cross firing.
I can see how those set ups could have a problem with cross over due to the close proximity of electrodes and high tension sources.
I can see how those set ups could have a problem with cross over due to the close proximity of electrodes and high tension sources.
BUBBAS IGNITION
Well-known member
They weren't the first though...
Alfa Romeo GP cars of the teens were the first to use twin plugs.
Then Nash mass produced the Twin 6 & 8 engine from 1929 -1941.
In 1934, R&R Manufacturing, Robert Roof's company developed a twin plug flat head Ford V8 conversion for racing that utilized the Nash Twin 8 distributor mounted directly to the 3 bolt timing cover.
In 1939 Eddie Meyer was convinced by Sandy Belond to alter his cylinder head casting to accommodate twin plugs because Belond was working with Sam Hanks and Roy Richter to come up with a way to light a degreaser that they were using as a fuel additive and that additive was nitromethane! These facts have been verified by Ed Iskenderian who worked on the timing advancer of Belond's twin plug V8 roadster and by Bud Meyer who drilled the twin plug Meyer heads for Belond before the War.
By 1942 they had it figured it out and at a REVS Timing meet in 1942 the roadster ran 125.854 mph on Muroc dry lake.
I attached a pic of the Roof catalog, the Belond roadster's V8 with a Scintilla 3 bolt, 90-degree drive and the correct modifications to run the Nash Twin 8 with the Scintilla. The 2 bolt adapter, the one with 4 holes, was not produced until after the War.
Finally just for fun I added a link of the Belond dual plug engine running on nitro:
http://www.youtube.com/watch?v=WLFTO0Bx9-E&feature=share
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Last edited:
onecool1929
New member
Anybody know how to get a hold of Norm Frick. He has a dual distributor mount that runs two distributors for the dual spark heads. I am trying to get a hold of Norm Frick as I would like to run one of his set ups. Any help would be greatly appreciated.
Michael
Michael
Jason in TX
Well-known member
And then there were these:
denverslim
Senior Member
Bubba, how do we contact you?...slim
