Technical internal vs external resistor

Any preferences on coils with internal resister vs coil requiring external resistor and a ballast resister for an inline flathead 6 cyl. 12V engine?

 

I prefer the ballast with a ballast bypass arrangement for starting. Helps in cold weather when starter draw causes the voltage to dip when cranking.

 

Consider this - resistors create heat. A lot of heat. Heat can destroy a coil. Coils get hot enough as it is and it doesn't make sense to me to add more. External resistors keep their heat to themselves and should not be mounted too close to the coil or flammable materials. A bypass circuit is advisable, run off the starter circuit so it only comes into play while cranking. External, ballast resistor, same animal.

 

Truth be known, I doubt if any coil contains an internal resistor because of the heat issue. But there are coils wound with a higher internal resistance in the primary coil that don't require a ballast resistor. But using a ballast resistor with a lower resistance coil and the bypass will give better starting performance.

 

External. Keep the coil simple.

 

Use what you can find easily at any big name parts store.

No fun being stranded and not being able to source parts.

I use a standard resistor, with the heatsink bolted to the firewall, and a basic coil from something GM mid 60's.

(Got a spare in the trunk too).

 

I have always been a fan of simple and in this case that would mean a resistor coil. Now after saying that ,I just changed to an external resistor and the non resistor coil (with the bypass when cranking) for easier faster starts. And I think it does start a little faster.
So I guess simpler is not always better. Go with the external resistor with the bypass, you'll be glad you did.

 

Why is it that everyone****umes that coil failure is a concern ? I don't recall coil failures or replacements being a common place occurrence . personally , in 60+ years working with ICE' s , I only recall replacing 1or 2 !

 

Run 6V and you don't need a resistor

 

I’ve ran both ways, never noticed any difference starting or while running.

 

Just the same as with points, the quality of new ones just ain't there no more.

 

I've been using the Bosch 12V Blue Coils on quite a few builds. They are internal 3.5-ohm resistance coils - have never had a bad one. They are typically about $40 - $60 on Amazon.

 

No points is better!!

Ben

 

Yes when it isn't polite to point....

 

Diesel engines solve a lot of problems.

 

Compared to the $12 I paid for mine.

Hence I keep a spare.

 

Early Fords had ballast resistor under dash, drivers side. Pre-'46 they had that stamped steel resistor on top of the coil, at the front of the intake.
Remove that resistor (either spot) and 2-3 days driving would boil the oil out of the Ford coil.
But the engine sure had a hot spark for a couple of days! (Points didn't like it...)

 

I don't remember ever seen a resistor on a VW engine. As far as I know, they always ran an internal resistor coil. They made several million of them, so I haven't seen all of them, just a bunch...

 

VW didn't go to 12 Volt until the 1967 year model. I had a friend with one that was early 60's in the mid 70's who had a fit because he couldn't install the 12 Volt 8 track player he had bought in it.

Back to the original question, I always try to keep thing simple and there isn't anything much simpler than a standard 12 Volt coil and a ballast resistor and a resistor bypass wire.

It's not a good idea but if you do have a ballast resistor burn out you can usually get away with bypassing it and driving to the closest place you can get one if you are on the road.