Coil question
 

On a 34 V8 the owner has replaced the orginal coil at the dist with a modern coil mounted on the top of the manifold, this is still a 6 volt system and works very well but when the engine is warm it doesn't want to start,motor spins nicely with no stalls in between but it won't start, if you pull the truck it fires right up, the coil is marked Internal resistor and it is a 6 volt coil,I'm thinking it doesn't need the internal resitor but I'm not familar with the conversion from orginal coil to a modern coil.

Re: Coil question
 

34 has a wire resister under the dash. If that is still in the circuit , the voltage to the coil is too low.

Re: Coil question
 

Check the resistance of the coil (disconnect the wires to it and check across the terminals) and also check and see if any additional external resistors are in the circuit. The ballast resistor under the dash should not be used with this coil.

Re: Coil question
 

I would temporarily bypass the wire wound resistor mounted behind the dash (wire & 2 alligator clips) and see what this will do for restarting the engine after it is up to normal operating temperature. If this solves the problem, jumper/bypass this external resistor more permanently.

Re: Coil question
 

It does not need the internal resistor its a 12 volt coil Ted

Re: Coil question
 

Hi Everyone, nothing to add but clarification...

From original post...

Re: Coil question
 

Where does this comment come from? Do you know something that was not posted in this thread?

Re: Coil question
 

AS per instructions the resistor under the dash is out of the system.
The truck is running a6 volt coil on a 6 volt system, the only problem I can see is that the coil is marked internal resistor, I would not think that would be needed with a 6 volt system, thats what I am wondering.

Re: Coil question
 

It needs to be somewhere around 1.5 ohms, but your not going to know anything until you check the coil to see what it is. It's volts / ohms = amps. You need to limit the current (amperage) across the point to somewhere in the 4 - 5 amp range. 6.8 / 1.5 = 4.5 amps, 7.2 / 1.5 = 4.8 amps. A higher resistance in the coil could be limiting the current/voltage.

Re: Coil question
 

The markings on coils is very vague ,its a 6V that you can run on 12V because it internally resisted .

Re: Coil question
 

Where are you seeing the picture of the coil Ted? Are you just assuming any internal resisted coil would be for use with 12v? I don't know the answer to that, I would want to see what the resistance was.

Re: Coil question
 

Let me put the question another way.
Do I need an internally resistored coil on a 6 volt system on the conversion from stock coil to modern coil keeping the system 6 volts.

Re: Coil question
 

Personally, I don't see any way around using JSeery's formula to get the right answer. What's MARKED doesn't matter. What is actually there does matter. JMO

Re: Coil question
 

Is there a reason you don't want to check the coil? It's hard to answer your questions without knowing what you have. It shouldn't take 5 minutes to check it.

Re: Coil question
 

Why don't you get an original coil and wire it like it should be them it would
be easy to trouble shoot?? G.M.

Re: Coil question
 

The truck isn't here at the moment and I'm gathering info so that when I do get it here I can run thru a few checks

Re: Coil question
 

Now I see! Thanks for the clarification.