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Fixing a bad curve....

Discussion in 'The Hokey Ass Message Board' started by Dr. Fishstein, Jan 17, 2012.

  1. I have had the distributor in my car for a few months and have had a lot of advance problems. The subject is a MOPAR electronic ignition distributor from the early seventies, that is in my 1964 Plymouth Valiant.
    The current set up had a advance stop that was stamped 15 r which was giving me 30 degrees at the crank plus my intial of 12 which equaled 42 total and it was all coming in at 2200 rpms. The car was drivable but was prone to ping or knock. I mangaed to score another distributor out of the pull-a-parts and inside was the prize a stamped number 11 advance stop.
    This would give me 22 degrees at the crank plus my intial of 12 equals 34 degrees. I still have to change the springs and adjust the vacuum advance. I also purchased new 8 mm wires and platinum plugs Autolite 65's. The car runs much stronger and can tell with a llittle more tuning it will run even that much better....Alot of guys have been welding up the slots in the advance stop to recurve there distributor, which is a cheap and easy way to get more power out of your small block MOPAR...

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    Click me for a listen....
    http://s2.photobucket.com/albums/y19/mopar65/Running/?action=view&current=IMG_0211.mp4
     
    Last edited: Jan 17, 2012
  2. Gator
    Joined: Dec 29, 2005
    Posts: 4,016

    Gator
    Member

    Nice tech Pete!
     
  3. ray-jay
    Joined: Feb 23, 2008
    Posts: 200

    ray-jay
    Member
    from Buford GA

    Mopar dists are a major pita to recurve because you have to remove so much stuff just to get to the guts. On the plus side the quality is high and once you get it right you don't have to mess with it anymore.
     
  4. Thank you sir................
     

  5. Bruce Lancaster
    Joined: Oct 9, 2001
    Posts: 21,682

    Bruce Lancaster
    Member Emeritus

    Another thing about adapting later electronic distributors to earlier cars, applicable to all makes as far as I know:
    The electronic distributors became common about the same time as EGR became normal.
    A distributor st up for EGR will have way too much vacuum advance and will ping like crazy at part throttel if used without EGR (or on an EGR car with that system gummed up!).
    Replace vac can with one from earlier distributor or limit its travel. Many EGRS have degree number stamped on bracket. With GM, practically no passenger HEI's were non EGR and early cans don't fit, but heavy trucks have what you need.
     
  6. GMC BUBBA
    Joined: Jun 15, 2006
    Posts: 3,385

    GMC BUBBA
    Member

    Good post !!! I might add another tip or two to help us all.
    The Chrysler distributor doesnt often need any spring change as the springs are attached to a eccentric pin that allows adjustment thru a hole in the top. I just make a tool from a old flat bladed screwdriver by grinding out the center allowing the tool to fit the pin head ( seen in picture). Then the pin may be turned in and out changing spring tension. Heavy spring high end and light spring low end.

    Also note the reluctor is marked for rotation for propr rotor index ( 7 deg difference or 14 engine) make sure roll pin is in correct position or you will have high kv spark demand all the time ...

    Also the vac cans are also adjustable with a allen wrench put inside the can vacuum tube ....
    One of the most adjustable distributors on the market ever !!!!!!!

    Glad to help...:eek::D






     
  7. GMC BUBBA
    Joined: Jun 15, 2006
    Posts: 3,385

    GMC BUBBA
    Member

    Another note is the two parts you show are for different rotation distributors.....big blocks go one direction (front mounted) and small blocks go the other (rear mounted.
    The two parts shown are for two rotations of distributors....
     
  8. Are you talking about the advance limiter ? They both are out of small block distributors, the 15 came out of a 84 truck distributor and the 11 came out of a 78 roadrunner distributor both came from a small block.. which is clockwise rotation....???? Not sure if I follow your train of thought....

     
  9. ray-jay
    Joined: Feb 23, 2008
    Posts: 200

    ray-jay
    Member
    from Buford GA

    Welding up the slots only takes a couple of minutes. If you plot the original adv curve you can determine which end of the slot to weld up, the idle stop or the full adv stop. You get to chase your tail a little while getting the travel and the springs where you want them. Makes you appreciate the GM dist with all the adv stuff on top. Of course the Mopar set up is far better engineered and longer lasting.
     
  10. GMC BUBBA
    Joined: Jun 15, 2006
    Posts: 3,385

    GMC BUBBA
    Member


    Pete,

    Again great post.
    I was referring to rotor phasing in respect to reluctor and rotor location. I did look over my core bin today and didn't have both rotations laying around. I will find both for a phase comparison soon and add to this post etc.

    Jim
     
  11. Ah understand now... The reluctor I got was a NOS from a old parts house here in Louisville. I had to use the old rotor as everyone I come across is two tall for the cap I am using. It is another mystery I am trying to solve..... I did have to make sure the cap's number one fell in the right place, I used an old cap with a window in it near the number one terminal to phase it correctly. I elongated the slot on the vacuum advance canister a touch to get the cap phased correctly......

    Look forward to your next post.....

     
    Last edited: Jan 19, 2012

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