Distributor Shaft Endplay Spec?

Discussion in 'Small Block Tech' started by MrSony, Sep 28, 2019.

  1. MrSony

    MrSony Well-Known Member

    I've heard .010 to .020 to even .10. Is there a spec? Or is my shaft (hee hee) supposed to move up/down an 1/8 of an inch? Whatever half the thickness of the reluctor wheel is.
  2. hugger

    hugger Well-Known Member

    I have seen some move that much yes,..wont hurt a thing,..getting them to tight eats up the cam gear as it cant find its "happy place"
  3. knucklebusted

    knucklebusted Well-Known Member

    The harm in too much endplay is that timing can jump around when you rev it as the gear tries to walk the cam up or down the cam gear. I would measure it outside the engine, install it in the motor and see how much play is in it when it is seated in the oil pump. If you shim it at the bottom, you are making the shaft longer and you could push the iron gears into the aluminum pump cover. If it isn't more than .030 endplay when installed, I wouldn't mess with it. If it is more than .030 I would not shim it more than half on the bottom to keep it out of the oil pump.

    Example: Total endplay is .060 and you want .020. You install it in the motor and get a measurement of .040. If you were to shim it .040 it would be .020 static but .000 when installed in the engine. If you put .020 on the bottom and .020 on the top to get your .020 endplay, when it was installed you should be .020 and not be pressing the pump gear into the cover.
    MrSony likes this.
  4. Smartin

    Smartin antiqueautomotiveservice.com Staff Member

    End play is ok...side play is no bueno.
  5. MrSony

    MrSony Well-Known Member

    Aight. Thanks for the info all.
  6. sean Buick 76

    sean Buick 76 Buick Nut Staff Member

    Just install it and run the engine with a timing light hooked up and look for consistent timing... If it's too loose you will see the timing bounce around.
  7. MrSony

    MrSony Well-Known Member

    Timing does bounce around. Not more than a degree or two, but it's noticeable. Gear teeth are getting sharp too. Not sure if that's the issue or a lack of lubrication.
  8. sean Buick 76

    sean Buick 76 Buick Nut Staff Member

    Yes I would address that. The timing should not bounce. I use a little dist. gear oiller but a lot of people do not have issues without this mod.

Share This Page