Technical 364 Nailhead Ballast Resistor Issue

I have a ‘58 364 Nailhead in my 32 coupe - 60 over, 401 camshaft with stock ignition. Twice now it seems the ballast resistor has died. For those of you running the same or similar engine with stock points ignition, what ballast resistor are you using? Presently I am using the RU4 I have always used for sbc’s and flatheads ….

Thanks for any help you can give

 

What ohm coil are you using? I will dig in my pile of 364 stuff and see if I have a stock resistor. Look at the blade of your RU4 and see what the ohm rating is. I think the stock coil used a 1.5 to 1.6 ohm resistor.

 

Rule of thumb is the ballast resistor value in Ohms should be roughly the same as the coil primary resistance. Lower than the coil, it will draw more current and run hotter, higher less current. Try to be within .2 ohm of being the same or as close as you can get. These will get hot, use a wire-wound around a ceramic core for heat dissipation.

 

I am using a stock coil I got from Ross Martin out in Calif - there was nothing in his website regarding a ballast resistor. I looked online for the stock resistor and there are two numbers out there from ‘53-‘58 and not specifically stated for the ‘58 …..

Whatever the stock ohm resistance of the coil is what I should have.

 

Checking Rock Auto they show an RU10 as the correct resistor. 1958 BUICK ROADMASTER 6.0L 364cid V8 Ballast Resistor | RockAuto

I just picked 58 Roadmaster but this is what it shows in the Standard ign parts catalog for 58 Buick Roadmaster Ecatalog (standardbrand.com)

 

Thank you gents - I appreciate the help!

 

I had a counterfeit Chinesium coil burn up a resistor myself.

 

Do you leave the ignition on for long periods without the engine running?

 

Not intentionally or with any regularity but my start sequence is different. I have a pull switch under the dash that brings the car to start mode. I then push in the clutch pedal, and then a push button in my original column drop (where the key used to be) to start the car.

 

Is the resistor mounted where it can get a drop of rain water on it ? The cold water getting on a hot resistor can crack it. I have mounted them in a sardine can to shield them.

 

Hmm - something I had not thought of as I have a hood but no hood sides. However, the problem came about on a perfectly dry day, and the first time it was in a garage.

The sardine can is a great idea and I bet I can find a “vintage” one to complete the look! Lol!

 

Chrysler products of the 70's - 80's had a dual ballast resistor mounted in the center of the firewall. If you opened the hood when it was wet out, the water would drain off and hit the ballast. If a customer came in to buy one we recommended he buy two; one for the firewall and one for the glove box.

 

I definitely will buy two or at least have some alligator clips to bypass the ballast resistor in a pinch (which I did not have the other day!) to get me home ……

 

I finished digging thru my 364 stuff and found a couple distributors, but alas no resistors. I believe the RU10 is the right one though. I am going the lobe sensing Pertronix route on my 401, but with a set of points handy for spare. The jumper wire is a good insurance policy.

Nice coupe BTW. Haven't seen it around town...

 

I am always driving around town in the car. I have also been at Bruster’s cruise in on Thursday nights. I live around the 5 Forkscarea - where are you in town? ….

 

Why not get an actual 12 volt coil and ditch the balance resistor all together unless you want it there to look correct