What voltage does a Mallory Unilite dizzy need?

[ChrisS]

I've been having problems starting my Chevy. I've got a Mallory Unilite distributor with an Accel Super Coil on a SBC. The wiring has 2 ballast resistors in the circuit with no bypass. The problem seems to be a weak spark when the starter is cranking identified by connecting a plug to centre wire on cap.
The Accel coil instructions say you must use their ballast resistor in series with vehicles own - and this is what is wired. However I believe this coil is designed for points and in Accel's FAQs it does state for electronic ingnition the ballast isn't needed - but then makes an exclusion for Unilites!
The Unilite instructions tell me to make sure I use a ballast or I could damage the Unilite module. But then the wiring diagram connects the positive feed to the 12v side of the ballast??
On my car the Unilite positive is connected between the 2 ballast resistors and is getting only about 6-volts (measured without cranking). The coil is getting about 3v. This all sems too low.
I've searched on here for info and it seems the best thing would be to throw away the Unilite. But I must admit I'd like to fix it.
Perhaps I would be better to run a 12v feed from the starter post via a diode to the coil so it get as much voltage as possible for starting?

Neither the Accel or Mallory websites give info on what the cranking/running voltages should be. Anybody help or advise on this please?

[29stude]

Real steel told me that using an accel points coil would eventually damage the mallory electronic unit. So I ended up buying a Mallory coil specifically designed for electrinic ignition units (£20ish).

Running through 2 ballast resistors with no bypass same as you, and always fires first time.

Gav.

[weemark]

ive run a unilite dizzy with an MSD blaster2 coil for 10 years now and never had any problems, it runs through the ballast resistor that came with the coil.

test procedures are on the mallory web site for the unilite - http://www.malloryperformance.com/pdf/1214M.pdf - testing starts at page 5.

[langysrodshop]

Unilites need a constant 12v, it buggers them up if you run lower voltage, only the coil should be fed through the ballast resistors.
I ran a Unilite with a ballasted Promaster coil and never had a problem.

[ChrisS]

Thanks Gav, Mark & Steve.
The manual that Mark links is the one that is confusing me. At the top it states you MUST use a ballast resistor but then lower down gives a wiring diagram with it connected before the BR on the 12v side then the next diagram if your loom has a resistance wire, then connect on the lower voltage side!
I have tested the Unilite and it does 'switch' OK.
Must admit I can't see how voltage could be too high for the Unilite as its optically triggered so what can 'burn out'?
So do others run the Unilite on a constant 12v feed and run the coil via ballast resistor?
Would appear I need to consider a new coil/resistor combination to work with the Unilite too. What about using a 12v coil without any resistors?

[weemark]

chris i think your getting confused because of the way you are reading the document - forget whats written at the top, follow the diagram that relates to your setup.

its the module inside that burns out if the voltage is wrong.

[Holmsey]

I have used Unilite on my F100 and did on my last car to. But I used the Promaster coil as Steve use's, bit more expense but works a treat. Has the resistor built in.