Why is my Ignition dropping out?

[CompOrangeSN95]

anyone know anything about ballast resistors? My car is running a carb and a standard mallory ignition with a dual point distributor, I was getting 14+v at the coil so I installed a ballast resistor and now I'm only getting 7v... I feel like I should be somewhere around 10-12v. I'm not sure if I got the right ballast resistor. Anyone know what I'm talking about or have any info they can share with me? My car runs great but shuts down after warming up and I'm pretty sure it is my ignition...

 

[CompOrangeSN95]

okay, so I figured out the ballast resistor and it's what I need. What I can't figure out now is why I loose ignition after the car has been running for a few minutes... It runs awesome even when it comes up to temperature, but a few minutes later (5-8) it starts missing and back firing and eventually shuts down.... I'm baffled and starting to get pissed the fuck off. Anyone know what I could be missing here???? Again I am running a standard malory ignition (no box) just coil and distributor.

 

[mikey94gt]

Kinda sounds like either the ballast resistor is soaking up the voltage (fat chance) or the clearance between the ignition pickups in the dizzy are opening up when it gets hot, not sending the right signals to the coil.

 

[CompOrangeSN95]

do you know how I could check that?

 

[CompOrangeSN95]

never mind, it's a duel point distributor...

 

[mikey94gt]

Hold up... does it have a condensor? swap that out... and go from there. I was thinking electronic for some reason.... It does have points, right?

 

[CompOrangeSN95]

hmmm, it is the one that came with the dizzy, you really think swapping it could make a difference?

 

[mikey94gt]

It could... and they are cheap. also, set the clearance on both sets of points, and clean them well. they like to get carbon buildup (courtesy of DC voltage), a bit of 400 grit sandpaper or 0000 steel wool does the trick.

A side point, you have to have a coil that is meant for the points setup, so no E-coils, etc like the stock SN-95 coil. the old school oil filled round coils work the best, like an MSD Blaster 2.

 

[CompOrangeSN95]

yeah the coil and dizzy are pretty much made for each other here is a link to both http://www.summitracing.com/parts/MAA-29217/
http://www.summitracing.com/parts/MAA-2555101/ I can't imagine there would be any build up on the points... it's brand new

 

[mikey94gt]

COol. so, i would replace the condenser, set the clearance on the points, and check the power to the coil when it gets hot. that should get you on the right track.

 

[CompOrangeSN95]

the power to the coil when it's hot is right at 7v. I'll have to bust out the feeler gauges and set the gap. I didn't think that would be something that changes as the car runs...