Ballast Resistor Question

Tim:

Don't know how he took it apart and put it back together. I will assume that he put it back the way he found it. As mentioned, he DID clean the corroded wire connections at the resistor before reinstalling the old resistor. That appears, from where I sit, to have rectified the situation. The JEEP has been sitting outside for a few years thus, the corrosion (it's a cj5 chassis and drivetrain with a 3B body on it).

 

My FSM lists Delco coil pri resistance 1.28 to 1.42 ohms Prestolite coil pri 4.25 to 4.60 ohms.
Ballast resistor Delco resistance 1.80 ohms Prestolite resistance .495 to .605 ohms.

 

I dropped the ball on this one fellas. I'll try to get you some numbers. My testers have failed me, or I have failed them by not checking/replacing the batteries. Gonna do that tomorrow and check the new resistor. I was unable to get a read from the old one since my tester wasn't working. The JEEP's distributor cap does NOT have the dwell window in it. So, I guess that means it's a Prestolite distributor.

My apologies for dragging my feet.

 

So, here is the new resistor that he bought. Testing it today made the the needle on my tester, set to OHMx1, barely move. So, it should be the right resistor, or at least compatible, for a Prestolite distributor, going by what has been discussed.

 

It's hard to test low resistances with a consumer meter. Touch your leads together and that's your baseline. Then test and note the difference. Might work better to put say a 5 ohm resistor in series with the test, and see how the reading changes with or without the ballast resistor in series.You can also make a voltage divider with a separate low resistance and measure the voltage across the ballast resistor, then calc the resistance from Ohm's law.

 

2X on what Tim says. I was going to jump in on this, but he covered it quite nicely. I did this same kind of setup with a Kawasaki two-stroke I built up. I installed 3 Marine coils in the bike, one each for each cylinder (didn't have true HEI back then) to get a hotter spark. It was great until I found out that my points were "ate-up" after about 1000 miles. I knew the capacitors were good, (these help to save your points from damage when they open and close) so the only thing that could be creating my issue was the hotter coils. I got a ballast resistor out of an old AMC Gremlin and wired it in with a switch that would short out the resistor for starting, or racing (gave me full voltage across the coils) and then I would open the switch to put the resistor back in the circuit once the bike was warmed up and running well and I was just cruising. That ballast resistor was around 1 ohm as I recall.

 

My vote is yes. I put a new one in a 69 Bronco and it smoked big time for a minute or so.