Mallory Unilite Issue

[BoureeOne]

Running a Mallory Unilite on my 347. Turned on ignition, everything is good, both fuel pumps come on ( Fitech with FCC and frame mounted low pressure pump ), turn key to start it, and my brown ground wire coming out of the distributor goes up in white smoke. Any suggestions...….

 

[Joe473]

Running a Mallory Unilite on my 347. Turned on ignition, everything is good, both fuel pumps come on ( Fitech with FCC and frame mounted low pressure pump ), turn key to start it, and my brown ground wire coming out of the distributor goes up in white smoke. Any suggestions...….

If that brown wire was the brown wire into the engine harness that wire actually is hot in crank from the I post on the starter relay. There is no fuse on early harness for that wire its direct from relay through cab and to coil from what i remember to bypass resistor wire in start so it will burn the wire if grounded due to no fuse.



Sent from my SM-G900V using Tapatalk

 

[BoureeOne]

The brown wire I am speaking of is the Unilite harness.

As in the diagram below.

 

[bax]

For the ground wire to go up in smoke it has to have a dead short. Power got to it somehow. Check the plug and terminations to try and find how it got power on it.

 

[BoureeOne]

For the ground wire to go up in smoke it has to have a dead short. Power got to it somehow. Check the plug and terminations to try and find how it got power on it.

I was thinking the same thing, just need to figure out why when juice is sent to starter. Have to figure the module is fried inside. Wire melted coming out of the distributor to the connector. Just got hot between the connector to the battery negative.

 

[Broncobowsher]

Bad ground between battery and engine. Trying to start the starter was trying to pull a few hundred amps through whatever ground it could find. In this case it happen to be the Unilite ground.

 

[BoureeOne]

Found this on a Mustang Forum. I think the highlighted part clearly explains what I did wrong....


I hear so many myths and partial truths about Mallory ignition modules that I thought I'd try posting the facts on a the forum to clear things up.

Mallory has three types of modules (not including the new rev limiting HEI module) that fit inside the distributor: Unilite, Magnetic Breakerless Ignition (MBI) and the new E-Spark. The Unilite and E-Spark are similar but the E-Spark is manufactured on automated equipment to reduce manufacturing costs so that the E-Spark conversion kits can be sold at about the same price as a Pertronix. The MBI uses a similar circuit but uses a magnetic pickup as a triggering device rather than an optical pickup.

The Unilite and the MBI are available in complete Mallory distributors. The Unilite and the E-Spark are available in conversion kits for stock type point distributors.

All three modules were originally designed to replace point style ignitions. Point style ignitions use coils with high primary resistance and ballast resistors (or resistor wires such as used in AMC, Ford and GM). Thus, the Mallory modules were designed to use a ballast or resistor wire.

Unilite, MBI and E-Spark modules (and Pertronix) are basicly electronic replacements for points. They are not amplifier boxes like a Hyfire or an MSD box. They are simply a way to get rid of the points. The spark output is usually a little higher than points due to the increased dwell time (and you don't have to worry about point bounce) but the output is not significantly greater than points. HEI type modules or external amplifier boxes are the only way to significantly increase spark output.

All three Mallory modules wire the same way. There are three wires:

The brown wire is grounded to the engine. Make sure you also have a good ground cable/strap between the engine and the frame/battery. Do NOT ground the brown wire from the module directly to the frame or battery. If you do, the brown wire will become a ground for the starter during cranking which will melt the brown wire and take out the module.

 

[bronconut73]

So a ground strap and a new module and you are good to go.

The Unilite is a great distributor.

 

[BoureeOne]

So a ground strap and a new module and you are good to go.

The Unilite is a great distributor.

I agree. Thirty years ago I built a couple of CJ7's and put 4bolt main 350's in them. I ran the Unilite's in them, and I never had a single issue with them.

 

[bax]

Good to learn. plus Broncobowsher was correct again. Made complete sense after I read his post.

 

[ntsqd]

My experience with Unilites has been that when they work they are pretty good. When they don't, then that's obvious. The problem that I and friends have experienced with Unilites is even when everything has been done right there is no predicting when they will fail. I got to walk several miles on a dark and damp night thru farm fields because of a Unilite.

I'd encourage this event be used as a sign and convert to a mag trigger (D-S II) or a Hall Effect (TFI) as both are far more robust designs.

 

[DirtDonk]

I agree.
Using light as a trigger is a brilliant idea! But magnetic triggers are not subject to many of the ills that befall a light trigger.

However, that's an argument for someone looking to buy new, or after any future failures. For now, you already have a new distributor and just need a replacement module for much less cost than a whole new distributor.
But speaking of that... You haven't really determined that it is indeed fried yet, correct? For now we're only assuming it is (with good reason, but no fact yet) it's dead, but you should make sure.
Be real nice if all you have to do is replace a section of wire and the trigger unit still works. Much quicker.
And much cheaper!

Good luck either way.

Paul

 

[bax]

I carried a spare module at all times.

 

[bmc69]

I carried a spare module at all times.

I've run almost exclusively Unilites in my boats, cars and trucks that have modified V8 engines, for about 25 years now. In 25 years, I've had one module just die and one that was intermittent, sometimes working only when I jumpered 12V directly from the battery to the positive lead on the module.

So I'd have to conclude that the Unilites have proven to be every bit as reliable as Durasparks I've run over the same period of years.

And yeah..I still carry a spare module with me at all times.


I'm anal about grounds. On all my builds, I run oversized cables (I make all of my own) from battery(s), to starter, to chassis, and to engine. Everybody gets grounded to everybody else with at least 1 if not 1/0 cables.

 

[ntsqd]

In that same time frame none of the 6 or 7 D-S II conversions that I've done has ever had a module failure. All modules were junk yard sourced.

 

[bmc69]

In that same time frame none of the 6 or 7 D-S II conversions that I've done has ever had a module failure. All modules were junk yard sourced.

I've had at least two D-S modules and one pickup fail over about the same period. So I call it even; both are very reliable ignition setups.

And when it comes to D-S components, I much rather have an old/used Motorcraft OE or Standard Blue Streak module than anything you can buy at an Autozone..for example.

 

[BoureeOne]

What are the thoughts on the two modules available. There is the 605 and the 6100M. The 605 is suppose to be the factory replacement and cost $113. The 6100M is suppose to be a direct replacement and cost $57.

 

[DirtDonk]

I was under the impression (from memory) that they were the same thing. But I can't guarantee that anymore.

Does the book happen to define the difference between "factory" and "direct" replacements by any chance?%)

Paul

 

[DirtDonk]

I should add that I've never seen a Unilite module that said "E-spark" on it.
The reason that popped into my mind was that just before Mallory bit the dust (got bought, sold, torn up and thrown away except for a few parts) a couple of years ago, they had the best distributors on the market in the form of their "E-spark" and "something other spark" distributors.
They were very trick in every way, and used electronically controlled advance via an internal computer that took into account all rpm and load levels. Had a small vacuum fitting sticking out the bottom of the unit for a MAP sensor function.
One version even had multiple spark throughout the entire rpm range.

These were very cool setups, but were basically Mallory's last-hurrah and I never heard much about them as far as sales were concerned. Should have lit the world on fire with their better mousetrap, but wrong part at the wrong time I guess.
Released not long before the recession hit, so I suppose timing is everything.

Anyway, all bitchin'ness aside, the use of the "e-spark" label is a bit confusing.

Good luck with the decision anyway. I'd call someone that should know (whoever owns them now, MSD I think?) or Summit or wherever, and see if they can give you a good reason to spend double for the first one.

If not I know which way I'd go!

Paul

 

[ntsqd]

I've had at least two D-S modules and one pickup fail over about the same period. So I call it even; both are very reliable ignition setups.

I can not agree with that statement. Nothing Mallory has made in the last 20+ years deserves that description. Some of the original Accel points stuff was exceptionally well designed, but since their purchase by the same holding company as Mallory it has all been dropped and replaced with re-badged Mallory product. From their inception to about the middle 60's Mallory stuff was the best you could buy. Has not been that way for a long, long time.

And when it comes to D-S components, I much rather have an old/used Motorcraft OE or Standard Blue Streak module than anything you can buy at an Autozone..for example.

+11teen!!!