Best coil for '30 A
- Thread starter Kirk1963
- Start date
Purdy Swoft
Well-known member
They recommend increasing spark plug gap for hotter spark. I run mine at .035 and its plenty hot. I run the air gap at the rotor tip at .035 also. The .035 gap at the rotor tip actually gives any model A a hotter spark. I didn't really want to push the envelope. I figured that the matched gaps at the plugs and rotor tip was good enough for me. I figure i'm already as hot or hotter than electronic as it is. I'm running the improved points cam that doubles the spark. I'm sure that more gap to a point will give hotter spark but the hotter the spark the hotter the coil will get. I'm going easy on mine.
Last edited:
H. L. Chauvin
Well-known member
Hi Purdy,
Thanks for giving us your recent past information on the 1.5 Ohm Petronix Epoxy 40111 Flamethrower recommended by Petronix for 4 cylinder Model A's -- got one in the mail yesterday.
Written instructions report that because of a Flamethrower's approximately 15% increase in voltage, whatever the manufacturer recommends for a plug gap, the gap can be increased or enlarged & the Flamethrower can handle it.
Years ago I used to subscribe to "Secrets of Speed" magazine founded by Mr. Charlie Yapp in 1991.
In calling him he mentioned an article from the September/October 1963 Restorer whereby it was reported that through experimentation, higher speeds could be obtained by increasing Model A spark plug gap to 0.040" to even 0.050"; however, they recommended carrying an extra coil just in case the coil got hot & burned up -- LOL.
In another area it was mentioned that Model A gas mileage could be increased by 10% - 15% by widening the spark plug gap.
Also that it took 12,000 volts to jump a 0.035" plug gap & 3,000 volts to jump the rotor gap; hence, minimum 15,000 volts under perfect conditions; however the original point/condenser/coil system was designed to produce 22,000 volts -- whereas the Flamethrower throws 40,000 volts.
These Secret of Speed magazines have too much detailed information to list here.
Thanks for giving us your recent past information on the 1.5 Ohm Petronix Epoxy 40111 Flamethrower recommended by Petronix for 4 cylinder Model A's -- got one in the mail yesterday.
Written instructions report that because of a Flamethrower's approximately 15% increase in voltage, whatever the manufacturer recommends for a plug gap, the gap can be increased or enlarged & the Flamethrower can handle it.
Years ago I used to subscribe to "Secrets of Speed" magazine founded by Mr. Charlie Yapp in 1991.
In calling him he mentioned an article from the September/October 1963 Restorer whereby it was reported that through experimentation, higher speeds could be obtained by increasing Model A spark plug gap to 0.040" to even 0.050"; however, they recommended carrying an extra coil just in case the coil got hot & burned up -- LOL.
In another area it was mentioned that Model A gas mileage could be increased by 10% - 15% by widening the spark plug gap.
Also that it took 12,000 volts to jump a 0.035" plug gap & 3,000 volts to jump the rotor gap; hence, minimum 15,000 volts under perfect conditions; however the original point/condenser/coil system was designed to produce 22,000 volts -- whereas the Flamethrower throws 40,000 volts.
These Secret of Speed magazines have too much detailed information to list here.
Coil up or coil down?
I checked the normal vendors and they just list the coil as 6volt or 12 volt. No comment about epoxy or oil filled. I have a 28 Tudor with the regular vendor coil. It sounds like oil. It is positioned facing down with the wire connections on the bottom. Is there a difference between the regular vendor coil and the 6volt Flamethrower coil? If I change coils do I need to flip the coil? I have never seen a picture of a Model A with a coil flipped up??
Confused?
REB
I checked the normal vendors and they just list the coil as 6volt or 12 volt. No comment about epoxy or oil filled. I have a 28 Tudor with the regular vendor coil. It sounds like oil. It is positioned facing down with the wire connections on the bottom. Is there a difference between the regular vendor coil and the 6volt Flamethrower coil? If I change coils do I need to flip the coil? I have never seen a picture of a Model A with a coil flipped up??
Confused?
REB
Purdy Swoft
Well-known member
The epoxy filled flamethrower coil is mounted just like the model A coil with the wires at the bottom. Post number 8 on this thread shows my epoxy filled flame thrower coil mounted on my roadster. I don't know about all of the vender coils. If you shake it and detect licquid inside, its oil filled. I don't think that the 6 volt coil I got from Snyders a few years ago was oil filled. There is a big difference between the vender coils and the flame thrower coil. The flame thrower coil gives electronic like performance with a stock points model A distributor distributor. Instant starts ,clean spark plugs and the engine will run so much more efficiently that you will have to idle it down the first time that you start the engine after installing the flame thrower coil. You get more power from the fuel with more complete combustion. Increasing the spark plug gap to a point will increase spark. I run the 3.0 ohm version on 12 volts on my roadster and love it.