[Fiftysix Chevy]

I titled this that way to maybe invoke interest. After nine years of operation, the Procomp multi-spark ignition (MSD clone) I was running failed, that cost me $75 to get the car home. Well my question is this. I am looking for opinions on whether or not, using a MSD type of ignition really makes a difference. I am running a mild build 350 that does a nice job at making my drive exciting when I want it to (at least when it wasn't on a flat bed). Please give me your thoughts on which direction you would go, should I give up the "box" and go straight distributor. Another question about the distributor, it's a Mallory Unilite, is there a better module that will fit the Mallory housing that is also less prone to fail? So far is has not.

Thanks,
Jim

 

[zbad55]

I would just go with the RTR MSD Dizzy for your small block. Mine has worked perfectly for my SBC. IMO most people who run the box don't even need them for what they are doing,

 

[55mike]

I'm A Fan

On a mild engine, the MSD box likely will do little.. however, on my rowdy 355, the MDS box made a significant difference, especially at idle and tip-in. I no longer experience plug fouling and or "loading up" type issues. I also really like the MSD distributor, and "MasterBlaster" coil.

 

[Pops @ Tri-5.com]

Need to know how and if you are using a ballast resistor....From what I understand from those who have been dealing with these things for years, the MSD needs one and the Mallory Unilite needs two for their modules to survive.

Don't have time now....However, I can find plenty of threads here and at various other web sites to verify this information....Just Google MSD or Unilite and Ignitionman and you will come up with all kinds of hits.

 

[Dean]

I have the MSD Ready to Run and Blaster coil on my BBC and no problems so far.

 

[Belair-o]

Ballast Resistor?

I have the MSD Ready to Run and Blaster coil on my BBC and no problems so far.

Are you using a ballast resistor with your setup?
Thanks, Doug

 

[USA1]

Need to know how and if you are using a ballast resistor....From what I understand from those who have been dealing with these things for years, the MSD needs one and the Mallory Unilite needs two for their modules to survive.

Don't have time now....However, I can find plenty of threads here and at various other web sites to verify this information....Just Google MSD or Unilite and Ignitionman and you will come up with all kinds of hits.

I am going to have to look it up but I am 99% sure MSD 6AL instructions for Unilite call for no resistor. I know my 67 Camaro does not have one with this setup. It went 1500 miles during Power Tour last summer that way.

 

[55 Tony]

Need to know how and if you are using a ballast resistor....From what I understand from those who have been dealing with these things for years, the MSD needs one and the Mallory Unilite needs two for their modules to survive.

I'm running an MSD R2R for quite a few years how MSD told me to, that is with no resistor. Also until recently I was running an MSD blaster coil which has a lot lower resistance than a stock coil so the R2R was handling a lot more current than with a stock coil and/or a resistor and it's gone over 30,000 miles that way with no problems. I did cave in to peer pressure and replaced the blaster coil with a stock one recently with no noticeable difference in performance. If it kept working with the blaster coil I expect it to last a long time with the stock coil and no resistor.

 

[Pops @ Tri-5.com]

One of the things I learned from Dave on Uni-Lite is that they need dual resistors to run the units. After years of failed ignition modules, I took his advice, and have done the same for quite a dew more Uni-Lite applications over the ensuing years.

What his advice is, run the stock coil, stock resistor or resistor wire to it, just like stock. Then, Uni-Lite comes with a small resistor in the box, add this to the Uni-lite power input wire, between it and the positive terminal of the coil, instead of just putting the Uni-Lite power wire to the positive post of the coil.

This resists the coil first, as stock, then, adds resistance, lowering Uni-lite input volts down to what the module wants, between 9.5 and less volts.

In all the units I have done this to, the failures stopped, and, the ignition systems did not lose one iota of power output. They all run exactly the way they did with one resistor, or, no resistor, but now, they don't blow up.

I do know that Dave told me along the way, that Boots Mallory built the Uni-Lite systems to run at lower input voltage levels, and that he used a lot of MOPAR parts of the era, including a .60 ohm early MOPAR point system resistor, to be added to the stock 1.8 ohm GM systems. That is what I use, early point MOPAR resistor, any good auto parts store can get them. He even got me to use a 9 volt dry lantern battery to power up these ignitions when I spin them up on my distributor machine, no problems, no loss of efficiency with the lower input volts.

I can not, nor will not fault the man, every time I have used the dual resistor for a Uni-Lite, the result is the same, works beautifully, no problems. Can't beat that.

Willard Thompson

 

[55 Tony]

I don't think I read all through that before Pops. If running a stock coil with 2 resistors as said above, you will without a doubt have a weaker spark than from a bone stock set up. No doubt about it. Maybe it's enough spark to run OK, but for sure it's a weaker spark than stock 1 resistor with points.

 

[Pops @ Tri-5.com]

From Dave Ray

"I just switched one from Comp 9000 Unilite to small body HEI for a person at my local CarQuest store, for his 455 Pontiac. This was the second Unilite he has gone through in less than 500 miles. He also had a Pro-Master square coil too, and it went by the wayside as well.

He, too, didn't have the second resistor in place, a sure way to kill a Unilite, fairly fast.

His symptoms were the same as yours, spark was weak, degrading, wouldn't start easily, was rich all the time, had stumbles and hesitation in acceleration, all the usual suspects of a weak and dieing ignition.

For a Unilite, you MUST double resist the Unilite module, or it will definately go blind. STOCK coils are just fine for a Unilite, as they have NO drivers to make the coil work any harder than a stock set of points, and won't make a "high performance coil" work any harder than a stock one will.

Most issues with Unilites is they are fed too much run voltage with just one resistor. The way they really want to be done is to run the stock resistor to the coil, and then, a resistor that comes in the box with the Unilite, between the positive side of the coil and the RED Unilite feed wire, further resisting only the Unilite module.

Another main issue with the Unilite is coils that are just not compatible with them, and failing coils. A resistance test will NOT tell you if the coil is going bad, as most coils layer short when hot, but read good when cold. The only real accurate way to test a coil these days is to run them on a coil tester, that duplicates actual running conditions. these machines are at stores like Auto Zone and others, and the attendant should know that the Mallory points coils test just like a resisted stock GM coil does, on their machines.

Also, check all grounds, from battery to engine and from the brown wire from the Unilite to the engine, if they are bad and/or dirty, you can get weak to no issues with the Unilite as well, but this is a fairly rare situation."

 

[55 Tony]

I just switched one from Comp 9000 Unilite to small body HEI for a person at my local CarQuest store, for his 455 Pontiac. This was the second Unilite he has gone through in less than 500 miles. He also had a Pro-Master square coil too, and it went by the wayside as well.

He, too, didn't have the second resistor in place, a sure way to kill a Unilite, fairly fast.

His symptoms were the same as yours, spark was weak, degrading, wouldn't start easily, was rich all the time, had stumbles and hesitation in acceleration, all the usual suspects of a weak and dieing ignition.

For a Unilite, you MUST double resist the Unilite module, or it will definately go blind. STOCK coils are just fine for a Unilite, as they have NO drivers to make the coil work any harder than a stock set of points, and won't make a "high performance coil" work any harder than a stock one will.

Most issues with Unilites is they are fed too much run voltage with just one resistor. The way they really want to be done is to run the stock resistor to the coil, and then, a resistor that comes in the box with the Unilite, between the positive side of the coil and the RED Unilite feed wire, further resisting only the Unilite module.

Another main issue with the Unilite is coils that are just not compatible with them, and failing coils. A resistance test will NOT tell you if the coil is going bad, as most coils layer short when hot, but read good when cold. The only real accurate way to test a coil these days is to run them on a coil tester, that duplicates actual running conditions. these machines are at stores like Auto Zone and others, and the attendant should know that the Mallory points coils test just like a resisted stock GM coil does, on their machines.

Also, check all grounds, from battery to engine and from the brown wire from the Unilite to the engine, if they are bad and/or dirty, you can get weak to no issues with the Unilite as well, but this is a fairly rare situation.

All that is, is a darn good argument on why not to use Unilte modules.
Don't take my word for it, ask anyone with electronics knowledge. You can't reduce the voltage going into the coil and get the same voltage out. It defies the principles of electronics. It's laughable at best.

Edit: Pops or anyone else, please don't take my response as a reply directly to Pops. It was intended for the author whoever that was.

 

[Pops @ Tri-5.com]

No one is disputing your voltage calculations Tony...Simply stated E=IR....However, how much of that 12V is required to accurately supply an ignition system the question...True HEI systems require a full 12 volts, no doubt....However points (or points replacement systems) requiring something less seems to be where the controversy lies.

 

[55 Tony]

No one is disputing your voltage calculations Tony...Simply stated E=IR....However, how much of that 12V is required to accurately supply an ignition system the question...True HEI systems require a full 12 volts, no doubt....However points (or points replacement systems) requiring something less seems to be where the controversy lies.

I found this quoted in your post:
"In all the units I have done this to, the failures stopped, and, the ignition systems did not lose one iota of power output. They all run exactly the way they did with one resistor, or, no resistor, but now, they don't blow up."

It says they "did not lose one iota of power output"

When in fact the spark DOES get weaker with less voltage on the primary of the coil. That is the false statement I disagree with.

 

[USA1]

Just Googled MSD 6AL with Mallory Unilite, MSD says no resistor required. I believe I have them wired with and without.

 

[Pops @ Tri-5.com]

It says they "did not lose one iota of power output"

When in fact the spark DOES get weaker with less voltage on the primary of the coil. That is the false statement I disagree with.

In theory, I agree with you....However, on the other hand, I do not have distributor machine, so I can not prove it one way or the other.

 

[55 Tony]

In theory, I agree with you....However, on the other hand, I do not have distributor machine, so I can not prove it one way or the other.

Ah you're coming around (in theory anyway! LOL)

It's not hard to test. If I had a Unilite unit here I'd have done it already and filmed it for all to see.

Now I'm curious, does his two resistor trick work on MSD's too? Or even one resistor? (since msd says to use no resistor)

 

[techguy466]

I had thought I stated to the moderator that I would never post on these boards again.....

Well, seems I was incorrect, and I will not lie about it, I am posting here, again, for the last time when I said I wouldn't.

Now, for the record, I have redone over 150 Unilites in my shop over the years I have been doing all forms of hot rod and classic car work, and ALL of them are using Dave Ray's two resistor setups, NONE have failed, NOT ONE. These were all repaired with a new, unbroken Unilite module, stock GM point coil, good wires, and spark plut gaps no larger than .035.

As far as spark output, I have three of the very large oscilloscope setups we all have seen in older shops, the ones we used to test electrical systems with, and ALL 3 tell me the same thing, and what Dave told me, a Unilite does not make more, nor less spark energy with no, one or two resistors in place, nor performance coils vs stock, NOT ONE MORE VOLT.

There are many cases of double resistors being used INLINE on many different DC applications, to run two different items at different loading rates from ONE feeder circuit. Even the lowly VW "Volt-A-Drop" had two different output posts, from ONE single coil resistor.

Also, both Dave Ray and I were personal friends of the late Boots Mallory, the person that started Mallory Ignitions, and, did the development and design of the Unilite. Dave told me that he got the double resistor fix directly from Boots, can't get any better than that.

So, now, I am gone from here.......

Enough of this, I have serious work to do, and it ain't worth wasting any more time here.

Willard Thompson

Personal attacks/accusations that were not constructively contributing to this thread have been removed by 557B210

 

[northwoods]

Interesting thread as I have an older Mallory unilite (5048201)and I'm looking for the "correct" ballast resistor that they recommend in their (Mallory's) installation instructions. Pn 700. Does anyone have a clue what this might be in a Standard Motor products or equivalent?? Mallory pn700 is no longer available. As to having an MSD box or not. My experience has shown an improvement on mild engines. And it's almost a necessity on wilder engines. I'd also say that someone who has successfully repaired 150 burned out units-probably knows what he's doing.

 

[Pops @ Tri-5.com]

Please Read

Just more info,

A ballast resistor, like ours, is simply a load coil, with the same values at either end, there is no dedicated IN and OUT end, nor polarity. If you put the power wire on an end, the other end will have the loaded volts be lower when the end user is active, such as the ignition system operating.

That said, MALLORY Uni-Lite systems like a few things, like double ballast resistance, dead stock coils, smaller spark plug gaps, good magnetic suppression, spiral core wire sets, and, they are by no means, even close to an HEI system, they make stock point levels of spark volts, NO MORE.

Coils, stock is great. (please note: there are NO drivers, dwell extenders, nor electronics in the Uni-Lite to increase dwell [coil voltage saturation], so, a "super duper, ultra high zoot, mega volt coil", when used on this system, simply AIN'T).

Wires, as stated above, a good set would be a pre-cut 7mm diameter replacement wire, the best ones being sold under the brand name Borg-Warner "Select" (O'Reilly has them, low cost, lifetime warranty, as good a wire as any "name brand performance" wire). 7mm diameter is just fine for any Uni-Lite, no matter the coil used.

Spark plug gap, NO LARGER THAN .032 MAX GAP.

Now, for the double resistor Uni-Lite systems like to 'live long and prosper' on. When we run a Uni-Lite on a distributor machine, Mallory specifies using a dry cell lantern battery to power up the Uni-Lite module, between 6.5 and 9.5 volts, NO HIGHER VOLTS. We already know the porcelain resistor on the firewall, or, the resistor wire in our vehicles rates out at 1.80 ohms, +/- 1 percent variance (this porcelain resistor can be obtained with NAPA p/n ICR13). This resistor (or stock resistor wire) would be needed left in place and operable between the power source (ignition switch), and coil + terminal. This makes for the first resistor, and drops working volts down to roughly 11.0 volts.

Second resistor would be installed between coil + terminal and RED Uni-Lite power input wire, to second resist the ignition module. The small porcelain resistor that comes with a Uni-Lite is actually a MOPAR derived one. Boots Mallory started his distributor business using over the counter Chrysler parts, like caps/rotors, coils, resistors, and the one for the Uni-Lite is still MOPAR spec. It is one used for the earliest 12 volt, single point ignition systems in Chrysler, Dodge, Plymouth, rated at 0.60 ohms. This second resistor further drops the line current down for a Uni-Lite to about 9.0/9.5 operating volts.

Yes, we hear all kinds of notable sources insist that the new Uni-Lite systems don't need a ballast resistor, but, when they constantly go blind, you will finally realize, they do. The other fallacy is that they make more spark energy than a stock point distributor. NOT TRUE, they have no electronics/drivers to increase coil saturation, and that saturation is the thing that makes the higher volts. The benefit is, Uni-Lite makes the same spark energy that a brand new set of points do, the first spark out of the new points, and don't drop volts off as it ages, not like the points do.

Almost every GM vehicle that used both 12 volts and points, use a separate wire from the 'R' terminal on the solenoid, to the + side of the coil, to add a full 12 volts to the system, AT FIRE UP/START ONLY. This full voltage drops off when the starter is disengaged as the engine starts, then, the system reverts to resisted power, fed through the ignition switch.

On very few GM vehicles that used points, usually military vehicles, trucks, the feed wire from the firewall bulkhead to the coil, doesn't go to the coil. It is run from the firewall connector, to the 'R' terminal of the starter, then, a single full copper stranded, non-resistor wire is run from the 'R' terminal, to the coil +. In this method, the IGN term feeds the firewall connector and resistor wire, the resistor wire feeds the 'R' terminal, and, on start up, full volts are used from 'R' to coil +. Then, when the starter is de-energized, the resistor wire feeds the coil +, through the solenoid 'R' terminal, for dropped current to the coil. This system setup is very, very rare.

Just a simple primer for correct care and feeding of your Mallory Uni-Lite.