Mallory unilite wiring question

[Zedyone_kenobi]

It is common knowledge that Mallory ignition modules do not really care for too much voltage. The instructions that came with my new dizzy say to hook up the red power wire to the 12 volt ignition source. Well on my car that was 13.8 volts... Poof went the first module.

Fast forward 90 dollars later with a new ignition module, and the instructions with that replacement module say hook up the red wire to the opposite side of the ballast to the 12 v ignition source.

Problem here is my ballast resister puts out like 12.4 volts down from 13.8

This would probably smoke the new resister. I have an extra OEM ballast I can hook up in series to the Mallory ballast that may step down the voltage enough.

I may try that tonight

Anybody else had this issue.

[Carl Beck]

I thought I followed the instructions that came with my Mallory UniLite - - I've hooked every one that I've put in different 240Z's over the years the same way.

The instructions that came with mine are Posted in this article as well - see if they are the same as the one's you received. I've always used two ballast resistors.

http://www.zhome.com/ZCMnL/tech/MalloryDist.htm

FWIW,

Carl B.

[Carl Beck]

System error - double Post - delete

FWIW,

Carl B.

[Zedyone_kenobi]

Carl I sincerely thank you. Mine look nothing like this. In fact the directions that came with the distributor are not the same as the directions that came with the new ignition module. Weird. I have never seen the directions you gave me, but I am going to give it a try with two resistors. I need to get the voltage in the 9 to 10 volt range or else I will cause another ignition module to expire...

That gets expensive!

[Zedyone_kenobi]

Okay, I hooked up my other ballast resistor to the car. I ran a jumper wire from the end of the Mallory Ballast which was putting out 12.38 volts (stepped down from 13.9V) to the OEM ballast (which was new as well)

Then I measured the voltage on the other end of the OEM ballast to see if there was a corresponding step down.

Nope.

Voltage INTO Mallory Ballast -> 13.9 V

Voltage OUT of Mallory Ballast -> 12.4 V

Voltage INTO OEM Ballast -> 12.4 V

Voltage OUT of Mallory Ballast -> 12.4 V

So what this means i probably need to buy yet another Malloy Ballast resistor.

[Ben's Z]

Quality piece

[Mike W]

Zedy,

I have not had the same high voltage issue that you speak of however I have heard of the Unilite's sensitivity to higher voltages as well as voltage spikes. I have been running mine for over two years now with no issue. However, about six months after I installed it I also found an active power filter that Mallory also sells and it is made for the Unilites. I also installed this shortly thereafter. Not sure if this is the reason that I have not had issues, but I figured it couldn't hurt. I was also surprised that there was no mention of this in the user's manual especially given that they do provide a warning about ensuring a clean power supply. The only downside that I have observed is that it is a PITA to mount. The cables to the mating connectors to the Unilite are very short and so it really limits the places where it can be mounted or secured. I ended up making a longer harness from the Unilite and mounted the filter on the inside of the fender.

In any case, here's a link to the filter. Not sure this is a solution for your high voltage problem but it might be something you want to consider in anyway.

http://www.streetsideauto.com/p/mallory-active-power-filter-29351/?utm_source=googlepepla&utm_medium=adword&utm_content=pla&gclid=CKiE6Z6t67ICFWaoPAodlToAAQ

Hope this helps.

Mike.

[Carl Beck]

It is common knowledge that Mallory ignition modules do not really care for too much voltage. The instructions that came with my new dizzy say to hook up the red power wire to the 12 volt ignition source.

Ok - When they say "12 volt ignition source" - - - I would think that is a general use of the term. Meaning something less than a 13 volt ignition source. Unless they said NO MORE THAN 12 volts - or give some additional specification.

Well on my car that was 13.8 volts... Poof went the first module.

Ok - 13.8 volts is NOT a 12 volt feed.

Fast forward 90 dollars later with a new ignition module, and the instructions with that replacement module say hook up the red wire to the opposite side of the ballast to the 12 v ignition source.

Problem here is my ballast resister puts out like 12.4 volts down from 13.8

OK - I wouldn't see that as a "problem".

This would probably smoke the new resister. I have an extra OEM ballast I can hook up in series to the Mallory ballast that may step down the voltage enough.

I would doubt that it would. The Ballast resistor is there to limit current - so it depends on the load put on it on the output side - with the engine running - - - the voltage should vary depending on if the points {trigger} is open or closed.

Ballast resistors work in a somewhat limited range - so if the OEM resistor is a standard resistor designed to work in the typical 12 volt system - it will only drop the current so much because it is designed to work with a certain load range.

I would think you would have to use a Ballast Resistor - designed to provide a more limited voltage given the same load.

I'd call Mallory and see if 12.4 Volts - is OK or not. I think it would be fine - where 13.8 would not be.

FWIW,

Carl B.

[Carl Beck]

Okay, I hooked up my other ballast resistor to the car. I ran a jumper wire from the end of the Mallory Ballast which was putting out 12.38 volts (stepped down from 13.9V) to the OEM ballast (which was new as well)

Then I measured the voltage on the other end of the OEM ballast to see if there was a corresponding step down.

Nope.

That is most likely because the Load didn't change - and the first Mallory Ballast already limited the current being feed to the distributor.

So what this means i probably need to buy yet another Mallory Ballast resistor.

I could be thinking of this all wrong - but I don't think adding a second Mallory Ballast Resistor would do anything.

If you know for sure - that Mallory designed a distributor that can not take more than 12 volts - with no {ie "0"} tolerance for anything above that.... Then you'll have to get a Ballast Resistor that won't allow any higher voltage to pass though. You'll have to reseach the very technical spec's of the different Ballast Resistors on the market.

But Gee... a 12 Volt Battery puts out 12.6 Volts... I think 12.4 volts will be FINE. That is well withing the range of "a 12 volt system".

FWIW,

Carl

Edited October 6, 2012 by Carl Beck

[SteveJ]

Do me a favor. Disconnect both sides of both ballast resistors and find out the actual resistance of each. Also, did the Mallory ignition module come with any technical specs? I'm curious about its impedance.

[tlorber]

Stephen, if you are unable to get it going you could look into a ZX dizzy. I've had one on my car for about a year and a half with no issues. $60.00 on Craigslist.

[Carl Beck]

I've had several Mallory Unilites in several Z's - and never hand a problem with any of them. Sometimes the feed to the Tach can be an issue. For $60.00 you get a well used ZX distributor that uses very expensive modules, or you can convert it to run on a GM module. Then you have to worry about the timing curve suiting your engine or not. In most cases it doesn't. So different issues no matter what you do.

Crawford Z used to be willing rebuild and sell you a ZX distributor with the correct timing curve - but by then it isn't much less expensive than the Mallory.

Maybe I'm getting old {well no question abou that} - but to me it isn't worth the few dollars saved, to screw around with a used distributor. Especially after spending thousands of dollars on the engine.