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Can a distributor "go bad"

Discussion in 'The Hokey Ass Message Board' started by Leebo!, Oct 26, 2010.

  1. Leebo!
    Joined: Nov 22, 2005
    Posts: 800

    Leebo!
    Member
    from Yale OK

    THis might be a dumb question, but can a distributor go bad? I have been having a trouble for some time, and am ready to throw my truck and myself into a wood chipper. I can get it running, and get it running smooth by vacumm gauge. WHen it gets warm, it starts popping and misfiring. If i try to restart it, it wont, and cant turn it to any position to restart it. I thought my coil might be bad, but changed coils and it didnt help.
    Its a Mallory Unilite if that makes a difference.

    Im a shade tree mechanic at best, but have never had this much trouble!

    Thanks!
     
  2. fitzee
    Joined: Feb 26, 2003
    Posts: 2,862

    fitzee
    Member

    I have had them half wore out and still work. I have to ask what model are you talking,Ford,dodge, chevy?
     
  3. old lady's mad
    Joined: Mar 18, 2007
    Posts: 169

    old lady's mad
    Member

    they go bad all the time, unilite is a points dizzy right. most likely the bushings are worn in the top and expnding when hot , in turn not opening the points enough to fire the coil . try this close the points up to about 10 instead of 18. if that cures it , guess what . its worn out.
     
  4. Leebo!
    Joined: Nov 22, 2005
    Posts: 800

    Leebo!
    Member
    from Yale OK

    Wow, forgot important details.
    350 SBC. cams not stock, but not super lopey.
    How does the advance (vac) work? Would that make any diff when warm?
     

  5. Leebo!
    Joined: Nov 22, 2005
    Posts: 800

    Leebo!
    Member
    from Yale OK

    Old ladys mad-
    Can you elaborate what you mean by "closing" points 10 instead of 18?
     
  6. Unilite should be electronic.Could be a bad module
     
  7. 29AV8
    Joined: Jan 12, 2009
    Posts: 222

    29AV8
    Member

    yes. most people do not even realize it. I have changed several for customers here of late.
     
  8. Ebbsspeed
    Joined: Nov 11, 2005
    Posts: 6,257

    Ebbsspeed
    ALLIANCE MEMBER

    Agree, sounds like the module gets flaky when it warms up.
     
  9. 53sled
    Joined: Jul 5, 2005
    Posts: 5,817

    53sled
    Member
    from KCMO

    throw in a junkyard hei, only takes a minute to know for sure. I have 2 or three around.
     
  10. Leebo!
    Joined: Nov 22, 2005
    Posts: 800

    Leebo!
    Member
    from Yale OK

    IS the module replaceable on a Unilite? I have changed them in stock HEI's
     

  11. Yes
     
  12. chevyshack
    Joined: Dec 28, 2008
    Posts: 950

    chevyshack
    Member

    Can a distributer go bad? Hell yea! theres not one part that cant go bad on any engine. Your block can even go bad when it cracks or has a rod come out the side. Ive replaced a distributer on my dads truck and it was only 5 years old. Dont make them like they used to.
     
  13. Slick Steve
    Joined: Dec 4, 2007
    Posts: 321

    Slick Steve
    Member
    from Indy

  14. The most trouble I've had was with the "Mallory" uniltes... everything from bad bushings to bad sending/receiving units. The bearings would get so bad the shaft would death wobble and take out the senders as well as the cap and rotor.

    I never had any issues with their dual points except for one time a wire came off the spade post by the points!

    For race applications I pony up for MSD or if you can afford it... the Mallory
    Mags are a hefty unit!
     
  15. Leebo!
    Joined: Nov 22, 2005
    Posts: 800

    Leebo!
    Member
    from Yale OK

    YEah, Im leaning towards a new module, based on some of the stuff I have just pulled up on the net. I have been saying for a bit now that I felt the dist was the culprit. Hell, I have rebuilt or replaced everything but the air in the tires trying to trouble shoot this. Im out of things to change if this doesnt fix!
     
  16. mt94ss
    Joined: Jul 25, 2010
    Posts: 310

    mt94ss
    Member

    Another thought, is the engine an older rebuild? Could be a timing chain issue. Have you put a timing light on it to see if it is 'dancing' around? Also, I had a BB chev that the cam went flat and it did that too. Just have to do a process of elimination.

    I'd do a dist. swap first and go from there.

    Good luck!

    Later,

    Mike
     
  17. dynaflash
    Joined: Apr 1, 2008
    Posts: 506

    dynaflash
    Member
    from South

    get rid of the Unilite Module and replace it with a Pertronix unit. And yes they make a Pertronix to fit the Malory dist. The Unilite modules are not very good and one just cost me a 155 mile wrecker bill.
     
  18. old lady's mad
    Joined: Mar 18, 2007
    Posts: 169

    old lady's mad
    Member

    well evedently its an electronic unit not points. one other thing to look at as a posibility . if you have a tach . unhook it . they can go bad and ground out the neg. side . there are ways to test and see whats bad. with out waisting money just throwing parts at it . unless you have spare parts laying around or can borrow some from freinds.
     
  19. Unilites are very susceptible to voltage spikes. Mallory sells a filter to protect the module.Make sure all of your grounds are good. A bad ground will cook the module.
     
  20. GMC BUBBA
    Joined: Jun 15, 2006
    Posts: 3,420

    GMC BUBBA
    Member Emeritus

    The uni-lites usually fail when hot and work when cold. Change it to a pertronixs replacement unit.
    OR we can supply you with a built "bubbas" unit if needed......
     
  21. 42 chevy
    Joined: Nov 1, 2006
    Posts: 623

    42 chevy
    Member

    Do the Mallory's have a pickup coil, like a stock HEI? I had an OT pickup that did that and it was the pickup coil. You can test the stock one with an ohm meter, disconnect it from the module and test across the 2 wires when it is causing the problem (hot). It should be between 500-1500 ohms. Then check between each wire and ground, it should read infinite. If it is the same as a stock one and fails any of these tests replace it.
     

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