Best coil for '30 A

K

Kirk1963

Junior Member
Hi guys, I have a '30 and the coil is bad (cuts out after driving for 10 minutes or so and coil gets hot). Wondering whose coil everyone suggests? More interested in functionality than show, though the car was a show car before I bought it and is in very nice shape. Thanks!
 
I forgot whether I got mine from Mac's or Snyder's, although I was having ignition troubles at the time and purchased the Nu-Rex timing kit. The tech guys at Nu Rex said for 6 volt system make sure the resistance/resistor is 1.5 ohms, and for 12 v systems use 3.0 ohms version. I just looked at Snyder's website and don't see both options, although I was sure that's where I bought it. I tested it when I received it and sure enough, 1.5 ohms resistance. I don't think that I ever asked why the different ohms ratings were necessary, maybe someone on the forum could help with that?
 
Any of the coils that model A venders sell should work good. If you buy at a local parts house, you need to state the desired OHM or there is no telling what you may end up with. I agree with markyb, If you run six volts you need a 1.5 OHM coil. Twelve volt conversions need a 3.0 ohm coil because it is internally resisted. If you plan to mount the coil with the terminals at the bottom as originally mounted, I recommend an epoxy filled coil instead of an oil filled coil. Original coils were tar filled. For better performance I use the epoxy filled 3.0 ohm flame thrower coil from Pertronix on my twelve volt converted roadster. They also offer the same coil in 1.5 Ohm for 6 volt use. The Flamethrower coil gives electronic type performance with points ignition. I get instant starts, clean running spark plugs and power that I can feel in the seat of my pants
 
FWIW:

On many other Forums, like Mr. Purdy remarks above in reply #3, quite a few who have experienced coil problems report very cleaner spark plugs on many different types of cars after installing "Petronix" Flamethrower Coils; hence, resulting in their reporting dependable overall better engine performance & quicker starts even with the 1.5 Ohm coils on vintage 6 volt systems.

On line, I asked the "Petronix" Technical Support Department which coil would they recommend for a positive ground, 6 volt, 4 cylinder original Model A engine with standard original Model A distributor & with original points & condenser.

Their very sincere response:

"Hi,

Use the 1.5 ohm epoxy coil #40111.

You may or may not see performance gains on 6V systems.

Carl Alcocer
Technical Support
PerTronix Inc.
909-273-6007
www.pertronix.com "

They are only $32.00 or so with free shipping at amazon.com.

Hope this helps one with Model A coil problems -- some coils, when foreign made, do not last long.
 
Good info Mr. H.L. I think its a good deal. I paid more for the one that I got from Eastwood, nearly eight years ago and the shipping wasn't free.

I found out how much a performance type coil would help my model A, back in the ninties. I found a source for Holly bee hive coils and put one on the coupe. The Holly coils were 30.000 volt . I could feel the difference in overall performance . When I cranked the engine, it ran so much faster that I had to idle the carb way back. It ran so much better with the hotter spark and got more power from the gas. The bee hive coils didn't look original.

The Pertronix flamethrower coil is double the voltage output of the original 28-29 slant pole coil. The epoxy filled Pertronics coil is mounted in the same manner as the original coil and doesn't look that much different than other replacement coils that most driver cars use. The spark comes from the coil. It is less expensive to get good hot spark with a Flame thrower coil than converting to electronic ignition. I grew up with points ignition and know how to work with it. There is no module to burn out, everything remains the same, you just get better performance.
 
I'm leaning towards using the Petronix coils on all the A drivers I work on. I had one of the Model A vendor standard coils on my car and after less than 3 months the damn thing arced out inside and would not work. I'd rather pay double the price of the normal vendors than be stuck on the side of the road.
 
Here is a picture of the Flamethrower coil, taken when I was building our roadster.
Roadsterwithnofindersandnohood.jpg
 
If I read the PerTronix web page correctly, the coil for 6v applications is 40111 as noted above in post #5. The same coil for 12v applications would be 40611.
 
Here's what Bob at NuRex has to say regarding internal resistance


Points and condensers used in point ignitions and some transistor ignitions
operate best and last the longest when run with a 3-4 amp current. Your 1.5
ohm coil will provide that when run with a 6 volt system. When you have a 12
volt system you need a 3 ohm coil to create the 3-4 amps. You divide the
voltage by the ohms resistance to get your current into the points.
 
Hi markyb,

In your reply #11, look at top & click on the blue lettering for Flamethrower Coil or Flamethrower.

When new screen pops up, click on the Flamethrower box & you should see the 1.5 volt black epoxy one.

Maybe always best to call to see if it is epoxy filled.

The epoxy ones according to Petronix's written literature are supposed to endure more vehicle vibrations; however, this could get into a never ending engine balancing harmonic discussion. LOL
 
FWIW: The following coil information came from amazon.com:

While it’s the perfect coil to go with the PerTronix Ignitor breakerless ignition, our 40,000 volt Flame-Thrower canister coil can benefit virtually any distributor type inductive system.

Its higher voltage allows larger spark plug gaps for added power, smoother response and better fuel economy.

These coils are internally resisted so installation and wiring is drastically simplified.

Our oil filled coils offer great heat control for street driven vehicles, while our epoxy filled coils provide superior winding support for high vibration environments in off-road vehicles and boats.
 
I've followed what Purdy Swoft has recommended on the PerTronix coils:
one of my "A's" is a 6 volt and the other is a 12 volt. And we could not be happier, my "A's" and me!;)

Bob-A:D
 
Pertronix makes at least three versions of the 40.000 volt 1.5 and 3.0 OHM coils. There is a black oil filled version, a chrome oil filled version and the black with brown top epoxy filled version. I believe that there is another version for electronic ignition. I've still got the box that my 3.0 coil came in . I'll check the part number tomorrow. I'm running the 3.0 ohm epoxy filled version on my 12 volt converted roadster, pictured above. If the oil filled less expensive version is used, the coil will need to be mounted with the tower pointing up. If the oil filled version is mounted in the original way with wire connections at the bottom, the coil will over heat and fail prematurely.
 
markyb said:
can you identify which coil is for 6v systems and epoxy filled? The 40111 is shown as oil filled...

some distributors show the 40111 as epoxy filled, pertronics site is showing oil filled?

http://pertronix.shptron.com/p/40-000-volt-flame-thrower-1-5-ohm-black
Click to expand...

The PerTronix site is quite confusing, to say the least. This is what I found:

40,000 VOLT FLAME-THROWER (1.5 OHM) BLACK EPOXY Product #: 40111

40,000 VOLT FLAME-THROWER (3.0 OHM) BLACK EPOXY Product #: 40611

(the product number shown in the link quoted above is 40011, which is oil filled)
 
Last fall I was at a locale farm buying some "A" parts to finish my coupe poject when I noticed an old 30 firewall that must have spent the last 50 years out doors. Screwed to it was an original coil that was so badly pitted I thought it must be rusted through. The owner said I could have it if I could get it off. Had to grind the screws but I got it, took it home and put it on the back off the woodstove and left it for three months. When I tested it I found it produced a spark, after bead blasting , filling pits sanding and painting I installed it on the now completed coupe. Stated right up and is still going after 900 miles this summer. It's the only iffy part I used during restoration and I'm tickled to have an original.
 
I've been running an original coil on my 31 tudor going on fourteen years. It was rusty and had dings that I filled. I only paid five dollars for the coil. The slant pole coils that were used in 28-29 are hotter than the straight pole coils used in 30-31. All of the old original coils that I have found over the years have all still worked except one with a hole rusted through the top that I haven't yet tried. The original model A coils are tar filled. I may try patching the coil with the rusted hole just to see if it still works. If nothing else it will still make a good museum display, I seldom throw anything model A away.
 
Bob-A said:
I've followed what Purdy Swoft has recommended on the PerTronix coils:
one of my "A's" is a 6 volt and the other is a 12 volt. And we could not be happier, my "A's" and me!;)

Bob-A:D
Click to expand...

Ditto for me; I bought the #40611 3.0 ohm epoxy filled for 12V.

Be advised though, since this coil is internally resisted, it does get quite hot to the touch when operating. I called pertronix about it and they say it is normal on these coils.
 
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