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Technical Ignition break down,

Discussion in 'Traditional Hot Rods' started by Model A Mark, Sep 9, 2017.

  1. Model A Mark
    Joined: Apr 30, 2008
    Posts: 1,277

    Model A Mark
    from dallas
    1. Holley 94 Group

    Hey guys, I need some help.
    Ill try to make this as short as possible, I changed some parts and now Im having some problems I cant figure out .
    I have a Merc flat head, stock cam, Fenton twin carb intake, Holly 2110 carbs, Mallory unilite distributor, MSD 6200 box, Looks like MSD coil too.
    The car had a alternator on it when I got it,
    What I just did is, I put a Isky 400Jr cam, Isky springs, changed the lifters, valve job, Put a Eddy Meyers intake, soaked and cleaned the carbs, I actually re-routed the fuel lines from a inline T to a fuel block .
    I took off the Alternator and put a Generator and regulator on,
    Problem is, its acting like a electrical brake down around 3000 RPM, it runs great up till then,
    Not sure it is electrical, but sure feels like it.
    I clipped my volt meter to the battery lead on the regulator, and grounded it to the engine and ran it inside the car so I can see it while driving, when it starts braking down, volts are around 13.9 give or take .
    I thought the coil may be braking down, so I changed it with a stock coil I had laying around, didnt fix it.
    Id appreciate any help ...
    Thanks .. IMG_6556.JPG
  2. Mr48chev
    Joined: Dec 28, 2007
    Posts: 31,582


    Well my first thought is damn, that tape on the headers is frigging ugly. But it wasn't part of the question.
    If it worked before and you didn't make any changes to the ignition it's self or it's connections to the power feeds, I'd have to start looking into the electrical power supply. I could see it not having enough power for the ignition after cruising the gut on cruise night for two or three hours with the lights on at lower speeds where the generator might not keep up with the draw but that shouldn't be the case if the battery is fully charged and you are just firing it up. You shouldn't even need a generator or alternator to run the engine at full tilt for a number of passes down the quarter if you aren't running lights or accessories.
    Call me old fashioned but I still question the "what for" when guys start saying they have these fancy race bred ignition boxes on reasonably mild street rigs. If it is the ignition module that's good and maybe I haven't done my homework on it thinking that they were primarily race only setups for sub 12 second drag cars.
    Budget36 likes this.
  3. Model A Mark
    Joined: Apr 30, 2008
    Posts: 1,277

    Model A Mark
    from dallas
    1. Holley 94 Group

    You should see the frigging ugly pipes under the tape, lol ..
    ClayMart, Jet96 and loudbang like this.
  4. King ford
    Joined: Mar 18, 2013
    Posts: 1,473

    King ford
    from 08302

    Try unhooking the msd, they are fussy as hell

  5. Mr48chev
    Joined: Dec 28, 2007
    Posts: 31,582


    Ok you got me there. I just never have liked that stuff since it first started showing up on rat rods and then morphed over to just about everything.
    Maybe It comes from when my dad was an inspector at Boeing and every time he found a piece of tape on something in the plane where it shouldn't be he pulled it off to see what it was hiding.
    Hope you figure it out quick but if that battery is fully charged it should run great for several miles with no working generator or alternator. Those shouldn't be a factor until you get more amp draw with lights and what not.
  6. Bandit Billy
    Joined: Sep 16, 2014
    Posts: 9,296

    Bandit Billy

    No help but a shout out for the Led Zeppelin reference in the title!
    jimmysweden likes this.
  7. Sheep Dip
    Joined: Dec 29, 2010
    Posts: 1,572

    Sheep Dip
    from Central Ca

    Fuel Level in the bowls are correct?
  8. acpat
    Joined: May 10, 2016
    Posts: 12


  9. Model A Mark
    Joined: Apr 30, 2008
    Posts: 1,277

    Model A Mark
    from dallas
    1. Holley 94 Group

    Didnt change anything on the carbs, took them apart, cleaned them and right back together , Ill recheck them, I was thinking fuel pressure, theres 3 1/2 psi at the gauge, but I cant see that at speed .
    And it almost feels like its not doing it when I hold the RPMs up sitting still, only under a load, but Im not sure ..
  10. I've not worked around Unilite and MSD ignition parts, but is there a recommended maximum for the primary voltage with this equipment? 13.9 volts doesn't really sound excessive though. Does the coil get too hot to touch when the problem occurs? Is it mounted on its side or in an upright position, someplace where it can get a bit of air circulation around it?

    I've also seen mention that some electronic ignitions can be fussy about having "clean" working current. Could you maybe swap back to an alternator as a test? Or is there an electronic voltage regulator that's compatible with your generator setup?
  11. christmas tree
    Joined: Dec 7, 2009
    Posts: 339

    christmas tree

    Your timing could be too fast, had the same problem on mine and set the total timing at 22 deg. and the engine came alive on up to the top end.
  12. linechaser32
    Joined: Apr 8, 2006
    Posts: 1,246

    from Iowa

    I would check with MSD, but I don't think they will run with a generator. You need to stay with an alternator. MSD's use a lot of current.
  13. sunbeam
    Joined: Oct 22, 2010
    Posts: 5,767


    Charge the battery and disconnect the field wire and see what happens electronics don't like interference. The generator is the thing that you changed that makes the most cense.
  14. Petejoe
    Joined: Nov 27, 2002
    Posts: 11,415

    from Zoar, Ohio

    That's incorrect. Running an 59a for ten years with an MSD and generator.
    Change your condenser, install spiral core plug wires, not solid core.
    Finally set your plug gap to .040. Not stock specs.
    Last edited: Sep 10, 2017
  15. I would think that if the generator was the problem, it would be more likely to cause trouble in the idle range when there is very low output. What was the status of the voltage regulator? I would want to check to insure that it is working correctly.
    Did you polarize the generator after you installed it?
    It is a very long time since I had to look at one, but the points in the regulator could be oxidized. Another source of the problem could be the capacitors (condensors). If they are old units, it is possible that they could have dried out. There is the one in the distributor, but there may also be a radio suppression capacitor on the regulator. Some had them, and some didn't.
    In electronics, electrolytic capacitors are normally the first place to look when troubleshooting a device or a system.
  16. blowby
    Joined: Dec 27, 2012
    Posts: 8,602

    from Nicasio Ca

    You mentioned new valve springs...likely not you problem but I once had a broken valve spring, still holding the valve closed but light on pressure. Then engine would cut out at the same RPM regardless of load (which makes sense), not sensitive to load the way ignition or fuel problems are.
  17. Engine man
    Joined: Jan 30, 2011
    Posts: 3,480

    Engine man
    from Wisconsin

    Blues4U likes this.
  18. enjenjo
    Joined: Mar 2, 2001
    Posts: 2,578

    from swanton oh

    What he said. Generator "electronic "noise". The solution is to install a filter in the ignition circuit.

    I know it's from Mallory but it will work with a MSD

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