Ballast resistor
- Thread starter mikebell
- Start date
Charlie Stephens
Well-known member
Don't replace the engine to solve a problem that could be as simple as the resistor. Get a good resister and try it. You need a resistor, don't run without it. Talk to some of the distributer people if you need help (Bubba?). How about adding your general location to your profile, your next door neighbor might have a resistor they could loan you to try?
Charlie Stephens
Charlie Stephens
rotorwrench
Well-known member
If your relocator kit uses a can type coil, you won't need a ballast resistor in the circuit. The later can types use no ballast. If it is still using an old Ford coil then you do need one but you need one that doesn't open circuit or have too much resistance when hot.
FlatheadTed
Well-known member
It sounds like a voltage drop starter (to small wiring )wiring sucking all the juice from the coil ,wrong coil ,dump the resister ,or get a 1/4 " resister from Radio shack and wire that from the solenoid /starter terminal to the coil to give it a boost .You could also clean all your connections switch etc. ,Use a alligator clip on a long wire and clip on the resister to test to see were the drop is .Ted
gearheadbill
Senior Member
Rotor wrench: Sure glad I read your post. Converting my 40 back to stock coil from can-type coil...checked the voltage to the new (old-style) coil I just got from Skip Haney. It reads around 6 volts; i.e. little or no resistance. The previous owner probably removed the resistor to utilize the can-style coil. Looks like I need to crawl under the dash and replace the resistor. Thanks for the heads up!
Your original Ford resistor should read .5 ohms (1/2 an ohm) NOT 5 ohms. A 6 volt can type coil would generally need no external resistor. Lots of things to check out in the ignition system apart from the resistor. Like condenser, points, coil, plugs, HT leads, caps, rotor, wiring. A 302 OHV engine has all these items as well and all have to be in good order. Test each item and establish if there is a problem somewhere. Read up in some flathead books how to do it. I prefer to use the original Ford coil as mounted on top of the distributor than the can type with the adaptor plate. Regards, Kevin.
ford38v8
Well-known member
Bill, You may find that you do still have the resistor in your circuit, if your 6v reading was taken while the points were open. When the points are closed is when the resistor will do its thing and your reading should be about 4v.
gearheadbill
Senior Member
Thanks for this tip as well. Can't get my old man body under the dash while the car is up on the lift, but I will check this out ASAP.
Maybe this explains why yesterday I thought I was losing it a bit. I was sure I checked the voltage (a couple of days ago) at the coil and got a +/- 4v reading...check yesterday reads 6v. I have cranked the engine around some between the checks doing a compression test etc.. Thanks again.
gearheadbill
Senior Member
hopefully Im thinking about this correctly. I should be able to un-hook the wire from the dash (resistor in place or not) to the coil, then use a jumper from the battery (running thru a correct ballast resistor) to the coil ... for testing purposes. Hopefully remembering to unhook the jumper before I damage my new coil.
JSeery
Member Emeritus
Really should check the resistance on the coil so you know what you have. Most 6v can coils use direct 6v+ with no ballast resistor. But, it is going to depend on the coil resistance. You want around 1.5 ohms in the system, so if the coil is in the 1.5 ohm range, no ballast resistor. At 6v and 1.5 ohms you will end up around 4 amps. More resistance if you want less amps.