My car is an 82 Z28 with 305, holley 600Ccfm, edelbrock Mallory dual point now fitted with a petronixs ignitor kit & MSD coil. At the moment shes running on about 5-6 cylinders & I have fitted new plugs (0.045" gap) & just fitted Blue max Morso 8mm leads, still no difference. So I had a look at the ballast resistor & although the winding is not broken, the ceramic insert thats the winding is wound around has snapped hence making the connections wobbly! Would this effect the out put from the coil & cause the car to run on 5/6 cylinders!. I have checked the carb ect & all seems to be fine, also when earthing the plug against the engine, the spark is a dim orange colour

Cheers Damian

 

Orange spark is definitely too weak. That would account for the engine running terrible, or even not running at all.

Check to see if the spark coming from the coil to the dist cap is weak too. IF it's good there, then it's a cap/rotor/coil wire problem.

If the ballast is broken, it should be replaced no matter what. I'd do that before going any further with troubleshooting it. You should be able to get an appropriate resistor locally; in fact, a ballast off of any car that uses one, should be close enough to substitute, at least for test purposes.

If the spark is still weak, replace the module.

 

I'm about 99% sure, Petronix instructions tell you to bypass the resistor/resistor wire, and run at least 14ga wire in it's place.

I know that's the case for the two conversions I did...one on my '70 BBC, the other on my '59 6cyl.

I may be giving you bad info above.

Is the ignitor kit the conversion from points to breaker-less? If not, disregard my reply.

 

Thanks guys,

I have a new ballast resistor arriving tomorrow, see if that works! if not then I'll test the coil. The petronix is the coversion from points to breaker-less. The cap looks fairly new & the rotor is new as it came with petronix ignitor kit.

Hopefully get a result soon, the weather is stinking hot at the moment in the UK & its dam frustrating when my bloomin car wont run especially with T-tops..our summer doesnt last that long

thanks damo

 

I think you're still going to want to bypass the resistor.

Might also want to make sure the plugs are in good shape...running with weak spark may lead to some fouling.

 

I think Mike is right. An electronic conversion should not need a ballast resistor, and running one would very easily cause what you are describing. Points need one because the points are just switches, so you need a resistor to limit current or you just burn your points up. An electronic ignition limits current by nature, transistors only pass so much....

 

The Pertronix points-conversion kit is a different deal than droppin in an HEI distributor. I have been told by those that have installed them that Pertronix recommends keeping the ballast resistor/resistor wire in place. I'd contact Pertronix to get a definite answer.

 

Well as it happens, I just did a Pertronix conversion on the Mallory YF distributor in my boat the other day, and I just happen to have the instructions handy. Amazing how these things work out sometimes!

Now keep in mind this is just one model, and may not apply to all of them, but it's at least something straight from the horse's mouth as it were.

 

lol...I don't have a scanner

I do have an old set of instructions though (may not pertain to this setup).

On the V8 conversion, I used switched power from ignition to bypass the resistor for startup only...i/e when it's running, it is running voltage through the ballast resistor.

On my 6cyl, I forgot one important point as to why I bypassed it...I still run a generator and couldn't keep enough voltage at idle to keep it working.

Glad this topic did come up, since I'm swapping to an Alt. on the '59 in a few weeks...probably saved me the cost and time of having to get new parts