Ignition Resistor

Rowdy

Rowdy

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Anyone have a picture of the rerisor that goen inline between the switch and the coil? Going to rewire the ignition system on this 38, to see if I can make it run. Likely I need the resistor, but am not exactly sure what I am looking for. Very new to making a flathead run, but quite experienced with A's, so the resistor other than the later resistor wire used on later vehicles is abit new, although i understand the technology behind it. Thanks Rod
 
Rod, I think this is what you are looking for. Ed
 

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Thanks, I think I have one of the 37 Fordor if I do not find one on the 38 pu. How much resistance are they supposed to have? Thanks Rod
 
Resistance is rarely given in the catalogs, so just buy by application.
NAPA Echlin ICR 40, Standard FD 220 are '32-48 Ford. First see if you have one as shown above...it would live on the inside of the firewall near the hole where wiring harness goes through to engine.
 
Clip a volt meter on the coil, turn the key on, with a 6volt batt. you should have 6volts with the points open, turn the engine just a little untill the points colse, you should have about 3-1/2volts. Walt
 
Thanks, will be looking, sorting out the wiring and making enough of a harness to run will be abit tricky, Thankfully I found a wiring diagram on line. Switch is missing. so will carefully trace things backwards from the coil, omit what may be problematic and replace the esentials for now. No need for any extra expence til I see if it lives or dies. Rod
 

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you do know you can buy an internally resisted 6v coil, that way you do away with the resistor, if you do decied to use a resistor get a ballast resistor, when the ing is turned on the let 6v to the coil for a hotter spark and faster starting, they then slowly reduce the voltage to 3 or 4 volts to the coil
 
Thanks for all of the help and advice. Going to pull the battery out of the A saturday afternoon, mainly for today, going to measure things up for wiring and look over a couple of other things, Plugs and oil filter will be here tommorrow. Saturday morning going after the parts pickup. Also need to crawl under what is left of the 37 fordor and see how that frame is. The car was laying on its side when we found it, so maybe the frame is usable, both of the pickup frames are bad, one badly bent from being overloaded with scrap iron and the other is really rusted out. I know where several more frames are so may have to look them over soon also. Rod
 
No such thing as an internally resisted coil.No room inside a coil for a 60 watt 4 inch long resistor.The resistors heat would boil the oil and burst the case.
 
Looks like I have 4 of them, hopefully atleast one is good. The bad part is the insulator they sit on on all of them is cracked, hopefully for a short start up all is ok. Found a later (early 50's Ford) switch to mount up so I son't need to hotwire things. Anyone have a good quick cure for the starter button being froze up?
 
If you were to use a coil for a 49 thur 53 Ford, thats all you need just to start it,or any 6 volt chrysler coil from 46 to 55.
 
36 coupe said:
No such thing as an internally resisted coil.No room inside a coil for a 60 watt 4 inch long resistor.The resistors heat would boil the oil and burst the case.
Click to expand...
I hope this winds up in the right place, I am responding to the statement about no internally resisted coils. Interesting! I have heard the term internal resister so many times I just 'ASSUMED" IT TO BE SO. A quick search of the internet found no reference to internal resister. Anyone have info to the contrary?
Rainmaker Ron
 
I to am curiuos although buying more parts is not really in the equation. Trying to make it run with the parts I already have. No need to put more money ito it til i see if it lives or not. Then I will address the other problems and try to get it atleast to a drivable point (brakes, lights and tires). Not much else in my intentions. Rod
 
The only two 12 volt coils that I am familiar with are the ones that will take a full 12 volts, normally used on electronic ignitions and those that require a resistor between the coil and the ignition switch and used on point ignition systems. Ed
 
I have 2 coils that say "6 volts no resister required", thay came off my 1935 Fords when I went to original coils.
 
Rainmaker Ron said:
I hope this winds up in the right place, I am responding to the statement about no internally resisted coils. Interesting! I have heard the term internal resister so many times I just 'ASSUMED" IT TO BE SO. A quick search of the internet found no reference to internal resister. Anyone have info to the contrary?
Rainmaker Ron
Click to expand...


Its really a interpetation issue i guess.

The primary circuit of a coil is a resistor ( or maybe i should say it has resistance in it to please everyone).
Each oem has always offered a primary coil resistance specification so the mechanic could check the coils internal resitance.
So lets use a specific system with a 6 volt battery on a 1940 Ford, the oem coil has a resistance of approx 1.5 ohms and the under dash resistor is also approx 1.5 ohms ( rounding them off for explamation sake.).
The total resistance is 3.0 ohms and 3.0 divided into 6 volts would give the system ( under good conditions) a current flow of 2 ampheres.
This would be the expected current flow of a orginal 1940 ford with 6 volts.
The system is designed to use a coil with ressitance and a seperate resistor.
Now somewhere in the years a manufacture used a coil with a "internal" resistor of 3.0 ohms total and this coil woild not need the seperate ballast resistor ( like some of the 53 Fords etc)
This was often refered to ( and labeled on the coil) as a internally resisted coil.

Now if the customer used this coil WITH the ballast resitor the total resistance would be 1.5 plus the coils 3 for a total of 4.5 ohms.
4.5 ohms divided into the 6 volts would equal = 1.3 ampheres which would give a very weak spark.

Each piece of each ignition needs to be correct for the application.

I had this very car in my shop this week. Complaint was hard to start and poor running.
The fix was to check the coils resistance, check that is was in fact a internally resisted coil, and bypass the resitor. ( no longer needed)

Couple this with a bolt on battery terminal ( a volt drop) and the spark was very weak at best.......:eek:
 
Rowdy said:
I to am curiuos although buying more parts is not really in the equation. Trying to make it run with the parts I already have. No need to put more money ito it til i see if it lives or not. Then I will address the other problems and try to get it atleast to a drivable point (brakes, lights and tires). Not much else in my intentions. Rod
Click to expand...

It will run without a resister to just see if it will run. It would be hard on the points to run it any length of time.
 
Got ot to fire breifly today using the resistor that is there. Looks like it needs a fuel pump rebuild and the carb needs some cleaning. Also went and made a deal on a parts pu. It had a better radiator, radiator support rods, speedo, seat springs and the hood side filler pieces with the 85 HP badges. Likely some other usable parts. Still need to track down a hood locally. Te parts pu has later Merc. brakes on the frontend and has a 4 speed. Planning on bringing it home in 3 weeks so I can start sorting through what is needed and what is not. Thanks again for all of the help. Also looked at the resistors at NAPA and they are only .34 ohm, so not alot of resistance. Rod
 
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