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Voltage issues with my unilite dist.

Discussion in 'The Hokey Ass Message Board' started by 54BOMB, Sep 11, 2007.

  1. 54BOMB
    Joined: Oct 23, 2004
    Posts: 2,101

    54BOMB
    Member

    I have had two modules go out in the last two months. The first time I called Mallory and they said as long as I buy the power filter and use the Mallory coil they would send me a new module at no charge. I did both of those things and it ran fine untill the other day. I called Summit and asked about different distributors and what my other options were. He said that even if I went with some other brand a voltage spike issue could blow out any module.(although the other brands are not as picky as the Mallory) He said I MIGHT have an issue with a ground or a voltage spike with the alternator/generator. I can check all my gounds and I can put a volt meter on my battery while its running , how else can I check for a voltage spike? And whats to stop it from poping as soon as I start it? Maybe install a resistor to the coil to be on the safe side? Is that ok to do, it has a resistor built into the factory wiring. Its a 64 galaxie, 390 and its all stock wiring, except for the distributor.
    Thanks
     
  2. ibcalaveras
    Joined: May 30, 2006
    Posts: 599

    ibcalaveras
    Member

    Replace the resistor wire I had one go out on my 64 Ranchero. I still had points then it burnt my distributor just the same as your set up. 10 Gauge wire and Dist. resistor will work fine...
     
  3. squirrel
    Joined: Sep 23, 2004
    Posts: 46,136

    squirrel
    Member

    welcome to the wonderful world of unilite....they have a really bad reputation, sounds like you're just adding to it.

    Quit while you're ahead?
     
  4. 54BOMB
    Joined: Oct 23, 2004
    Posts: 2,101

    54BOMB
    Member

    I bought the unilite because my impala had one that ran great for years, I have no problem ( other than normal buyers remorse ) getting an msd or what ever I just dont want to do any more damage? Is checking the voltage across the coil enough or is there another diagnosis trick?
     
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  5. squirrel
    Joined: Sep 23, 2004
    Posts: 46,136

    squirrel
    Member

    start by checking out the ground situation, the ground wire (brown?) to the unilite module must have a very good ground connection, clean, not corroded, tight, etc.

    Most electronic ignitions don't pop when there is a power supply problem, the unilite really is a bad design, you're better off changing to something else, or at least keep a point dist in the trunk. Last stock rebuilt point dist I bought for a 390 was dirt cheap at the local parts store.
     
  6. 1950ChevySuburban
    Joined: Dec 20, 2006
    Posts: 6,206

    1950ChevySuburban
    Member Emeritus
    from Tucson AZ

    I went thru a couple of these modules earlier this year. Unilite wiring shows a ballast between the 12v and the coil, however, if you ask them it's supposed to go ahead of the coil AND the module.
    In other words, resistor before both coil and Unilite dist.

    I have mine hooked up this way, runs great, good spark.
     
  7. 54BOMB
    Joined: Oct 23, 2004
    Posts: 2,101

    54BOMB
    Member

    So you have the IGN wire go through a resister before the coil? That way the coil would never get a full 12V right? You dont have starting problems or weak spark issues?
     
  8. I use to run a Unilite, and thats the way I had mine set , I had no problems but friends of mine did. I've since gone back to dual points, simple and alot harder to screw those up....
     
  9. Ground Ground Ground!
    Make sure the brown wire has a good ground, then run a ground strap from the same bolt to the frame.
    If you realy want to give up on it, I believe mallory has a magnetic conversion for that dist.
     
  10. Yep and It never fouled plugs or loaded up.
     
  11. old beet
    Joined: Sep 25, 2002
    Posts: 5,750

    old beet
    Member

    Resister before the coil. Been running a Unilite for over 20 years on my 390 FE. Over 160K miles. Only had one mod go out, had a wire short. OLDBEET
     
  12. toadfrog
    Joined: Dec 2, 2006
    Posts: 299

    toadfrog
    Member
    from Arkansas

    Stick the Uni-Junk on E-day....

    Get a OEM ford dizzy from a 76' 390 and a dura spark box with blue grommet. And have no more worries.......
     
  13. Kamp
    Joined: May 27, 2006
    Posts: 358

    Kamp
    Member
    from Peoria, IL

    The Unilite will go out if you have more than (I believe) 9 volts going to it. The resistor knocks the voltage down to this 9V, but if you get a spike - like from a grounding issue, or even from a faulty voltage regulator, it will burn it up. At $100 a pop, it's kind of a risky deal, in my opinion... I've had people run them for years, and other people for days - before replacing them with points or MSD.
    The MSD does not look "period correct" but uses a magnetic pickup instead of the optical unilite. These run at the normal 12V, and as far as I know you can't really burn them up. They are pretty bulletproof. In fact I can't remember any distributors that failed... a couple boxes failed along the way I guess....
    I'm not sure if they have a "ready to run" for an FE, otherwise you'll need a 6-A or 6-AL (6-A with rev limiter) to run it.
    Kamp
     
  14. Kamp
    Joined: May 27, 2006
    Posts: 358

    Kamp
    Member
    from Peoria, IL

    Oh, and it doesn't take too many unilite modules to pay the extra for a 6-A box.... so the cost - possibly- could be even pretty quick.
     
  15. 54BOMB
    Joined: Oct 23, 2004
    Posts: 2,101

    54BOMB
    Member

    Thanks for all the answers, Im leaning towards an MSD, they sell a unit that is ready to go with out an ignition box. Still better get a review of all my electrical stuff to be sure.
     
  16. propwash
    Joined: Jul 25, 2005
    Posts: 3,858

    propwash
    Member
    from Las Vegas

    just quit screwing around and buy one of those great-looking Vertex "look alike" HEI "magnetos. I took out a very reliable Unilite Marine distributor (crab cap, brass vent screens) and although the Mallory ran fine for many years (I've had it in six different engines/cars), it was time for a "new look" and there's nothing with quite as much impact as a big fat Magneto

    dj
     
  17. btmatt
    Joined: Nov 15, 2006
    Posts: 227

    btmatt
    Member

    I agree that the Unilight is junk. We fought those on racecars till we went crazy. As noted previously, think about a good old factory points distributor with MSD6A as your amplifier. Good stuff man.
     
  18. Flat Ernie
    Joined: Jun 5, 2002
    Posts: 8,410

    Flat Ernie
    Tech Editor

    Mallory has changed the way the wire the ballast resistor at least once over the years. You can actually download both methods from the various websites that carry their wiring diagrams.

    I've run a unilite in a stroker 351 since 1987. In that time, I had one failure, which was my fault.

    They are a good ignition, but not tolerant of any voltage issues. Some interpret that to mean they're not a good ignition - I say, fix your voltage issues. ;)

    Are you still running a generator on your galaxie (I assume that's what it's on) - if so, I'd make sure you have an electronic voltage regulator. The mechanical VRs will arc as the points make/break causing voltage spikes. These spikes can be quite high & will definitely kill a unilite module.

    Duraspark with a late-model TFI coil will put out more voltage to the plugs than the over-hyped GM HEI & an accel coil.
     
  19. Travis9534
    Joined: Sep 12, 2007
    Posts: 1

    Travis9534
    Member
    from nevada

    I've been use the Unilite for years, as long as they are wired correctly and your not having any electrical problems they work great.
     
  20. LUX BLUE
    Joined: May 23, 2005
    Posts: 4,408

    LUX BLUE
    Alliance Vendor
    from AUSTIN,TX

    ya know...they make Mallory distributors with magnetic pick up's too.

    the conversion is easy, and no more expensive than a new module.

    Call Mallory. They will tell you what to do.
     
  21. 54BOMB
    Joined: Oct 23, 2004
    Posts: 2,101

    54BOMB
    Member

    A tech guy from Mallory was on here and sent me a PM, I called him and he went through some stuff with me step by step and I found where I had some stuff set up a little different than I should have, mainly the uni-lite ground location and the resistor wire in the main harness could be messing up the rest of my system, I also found out the new module is only about 37.00 not 100.00 like they used to be. The guy was super easy to talk to and Im going to try his sugestions and get it running. Ill let you guys know how it works out, Ill give Mallory another shot.
     
  22. squirrel
    Joined: Sep 23, 2004
    Posts: 46,136

    squirrel
    Member

    I hope it works ok for you....

    I think it would be neat to pack up all your Mallory stuff and send it back to where you bought it, and tell them you're talking to a lawyer about starting a class action suit :)

    seriously, the automotive environment is harsh, especially for aftermarket applications, and if Mallory's design has been susceptible to ground and voltage spike issues for 20+ years it tells me that they really don't have a clue how to design this stuff to be robust. Other companies don't seem to have similar widespread troubles with it....

    are you listening Mallory?
     
  23. kurt02gt
    Joined: Sep 12, 2007
    Posts: 2

    kurt02gt
    Member
    from Ohio

    Thanks for the kind words 54BOMB, we try to do our best to help our customers.

    Squirrel, here some info for you on why we see problem with Unilite Distributors:

    The Unilite really doesn’t care too much about supply voltage, as long as it is in the 6-18v range. What it DOES care about are coil current, and coil energy. The coil driver in the Unilite is a transistor that has certain maximum ratings, some which are mutually in compatible. For example – the maximum continuous current rating for the transistor is 14 amps, but you can’t have that much current in the ignition circuit with standard coils, because the energy level would be too high. The purpose of ballast resistance is NOT to control voltage, but to limit the current in the coil primary (which is what the transistor switches on & off). Ideally, for “normal” coils (with primary inductances in the 5-8 milliHenry range) the Unilite wants about 2 to 2.5 ohms total primary resistance. That means that the combination of coil primary resistance and ballast should be 2-3 ohms. This will limit the current to 5-6.25 amps with a nominal 14v electrical system. If you look at the latest instruction sheet, they show just a single ballast – whether it is in the vehicle loom wire or a separate piece. Older instructions showed two ballasts for those applications that didn’t have a loom resistance wire.

    <O:p</O:p
    At any rate, our (and most other) ballast actually increases in resistance when it gets warm. This allows a bit more current for cold starts, then lowers the current to reduce stress on the coil driver transistor. In addition, virtually all coils’ primary resistance goes up as they heat up, so that drops the current even more.
    <O:p</O:p
    Unilites normally fail because of other things. A number of years ago, we did a fairly comprehensive analysis of returned Unilites. What we found was that half of the returns worked without any problems! Of the half that didn’t work, about half of them had internal damage consistent with miswiring – two major problems were getting the red and green reversed, and getting the red and brown reversed. In both of these cases, you got significant excess current that either blew out the coil driver transistoror melted the brown wire. Of the final ¼ of the returns that weren’t obvious wiring errors, they had a variety of problems, many of which have been addressed in the latest redesigns. I’ve been with Mallory almost 25 years, and as far as I know, we have never had a Unilite fail of the installs we’ve done here. We have also built (I’m approximating, as I don’t have hard numbers) close to 1 million Unilite modules over the 30 years they’ve been in production, most of which worked (or are working!) just fine. Unfortunately, with that many, you are bound to have problems related to installations, random part failures, electrical problems in the vehicle, etc. and those failures are held up as examples of how “bad” the product is, when in fact, it has been very reliable.
    <O:p</O:p
    So, to wrap this up – the things that kill Unilites are bad installations, using a low-resistance coil with no ballast resistor, heat, and vehicle electrical gremlins. One of the worst is to have the battery connection come loose or have a high resistance. This causes the alternator output to shoot very high for a short period of time, and often, this will be enough to pop the control circuit in the Unilite. There are some other charging system problems that can cause similar glitches. The in-line power filter we sell helps clean up the power to the module, but it also has limited capacity for severe charging system failures.<O:p</O:p
     
  24. toadfrog
    Joined: Dec 2, 2006
    Posts: 299

    toadfrog
    Member
    from Arkansas

    "So to wrap this up &#8211; the things that kill Unilites are bad installations"

    Typical mfg answer.. ...It's always the customers fault......(At least 75&#37; of the time)

    Why is the "Power Filter" either included with or built in???
     
  25. kurt02gt
    Joined: Sep 12, 2007
    Posts: 2

    kurt02gt
    Member
    from Ohio

    We have done the studies and that is what came out of them. The real problem is not the installer, it is the poor instructions. We really need to update and improve on them. You can install according to our instructions and still be wrong. I have made requests and we are working on improving our instructions.

    The active power filter protects the red wire (12 volt) against voltage spikes and protect the green wire from feed backs and load dumps. You should not have to use the active filter but if you have a lot stereo equipment or a voltage regulator going bad it can help protect the module from voltage spikes or surges. Will it prevent it, no. So to answer your question, if your electricial system is working correctly you do not need the power filter.
     
  26. toadfrog
    Joined: Dec 2, 2006
    Posts: 299

    toadfrog
    Member
    from Arkansas

    Having been stranded 250 miles from home by a Uin-lite that worked perfectlly for months, and then just quit, I'll never run one again.

    I feel that they are way sensitive to voltage variations to be dependable. I only run magnetic pick-up style, I'm yet to have one fail. And no I'm nieave enough to think that will not.

    And don't get me wrong I don't have a hatered Mallory, you-all have some great products, just the Uni is'nt .
     
  27. cleatus
    Joined: Mar 1, 2002
    Posts: 2,277

    cleatus
    Member
    from Sacramento

    When I first put my car together I put a UniLite in it for no other reason than I liked the way it looked.
    For several years I had troubles with how the car ran. Various odd things that I mistakenly attributed to various possibilites and spent countless hours of frustration in troubleshooting and even paid professionals to try to diagnose.
    I put in two different power modules which seemed to have SOME positive improvement - at least for a while, but even then it never seemd to run quite like I expected.
    Finally, I decided "it has to be the distributor"
    I put in an MSD ditributor and ALL of the problems where instantly solved and the car has run consistently great ever since.
    That fuckin UniLite wasted so much of my time and money - I took and beat it to death on my driveway!
     
  28. toadfrog
    Joined: Dec 2, 2006
    Posts: 299

    toadfrog
    Member
    from Arkansas

    Mine ended up in a trashcan out side of a auto zone in Oklahoma City....
     
  29. FLAT-TOP BOB
    Joined: Aug 19, 2002
    Posts: 1,964

    FLAT-TOP BOB
    HAMB O'dex Editor

    in 1990 we put a used unilite from old wreck in my 1932. the module was dated 1985 and now after 22 years of use it's still going. nothing but good luck for me with unilites.

    now that said, i do carry a new one just in case!
     

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