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Technical Maximum RPM from a stock crab flathead distributor

Discussion in 'Traditional Hot Rods' started by Psychobilly Boi, Jan 15, 2012.

  1. Hi guys,

    Have a stock crab dizzy on my 286 and wanted to know what RPM these will handle. My ignition begins to break down at 3000rpm and gets worse from there. Holding steady revs at 3000 or above there I a noticeable miss fire.

    Danny
     
  2. Danny, Old bootlegers would add a extra points spring to the points and would gain higher rpm . I have an old friend that could explain this process as I have only heard him talk about it .I can call him if it would help and have him call you Pm me with phone info if I can help ...John
     
  3. flatjack
    Joined: Feb 13, 2007
    Posts: 941

    flatjack
    Member

    Should run higher than that. I've had them up to 5000 on my Sun machine. Get a good pair of points.
     
  4. Do you have your vac line out/off and dist brake 'just' nipped up??
     

  5. Hi guys,

    Thank you for the replies.

    The brake is off and I don't have the vac line connected.

    Can anyone recommend a decent source for a rebuild kit? Points, condenser etc.

    Danny
     
  6. Have you tried local yet? I know Johns Rod and Custom stock a fair few tune up kits (points and condensor sets) for the flatty. All useless to me as mines running Bedford/triumph points and a single set at that.
     
  7. joee
    Joined: Oct 9, 2009
    Posts: 474

    joee
    Member

    convert to pertronix
     
  8. That could be part of your problem, the brake should be on just to create a little drag to hold it steady.
     
  9. Bruce Lancaster
    Joined: Oct 9, 2001
    Posts: 21,682

    Bruce Lancaster
    Member Emeritus

    Don't know the outer limits, but it should go a lot past 3,000 with a decent coil. I know some repro points are garbage, some from actual ignition suppliers are good.
    I think running it up a bit with a dwell gauge should be informative...if points are NG, I would think dwell will go nuts at failure RPM, if dwell stays reasonable worry about the coil. Also, if temporarily bypassing any resistor in the system scores more RPM...coil.
     
  10. Harry o
    Joined: Jan 19, 2012
    Posts: 200

    Harry o
    Member
    from Georgia

    My neighbor put a late modle mopar in his flat head ... hes on here look up gerrald meacham ... He had to do minor grindiing but it works great ... Have you tried to up grade to Pertronix ignition .... Gerrald will tell you what he did just ask him ...
     
  11. Jimmy2car
    Joined: Nov 26, 2003
    Posts: 1,707

    Jimmy2car
    Member
    from No. Cal

    Human fly is correct. That dist needs a bit of drag to operate correctly. Spark scatter will occur without it
     
    Last edited: Jan 20, 2012
  12. swissmike
    Joined: Oct 22, 2003
    Posts: 1,297

    swissmike
    Member

    The crab style distributors are a dual point design and should be good for all that the motor is good for if everything s working ok.
     

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