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Technical How would you solve this flexplate/starter interference problem?

Discussion in 'The Hokey Ass Message Board' started by Just Gary, May 1, 2021.

  1. gene-koning
    Joined: Oct 28, 2016
    Posts: 2,566


    If the tooth count is wrong (could just be a counting error?), but close (like yours is) you will need more clearance on the sides of the tooth mesh. The drag against the flywheel teeth is why the starter drive is not disengaging.

    I would probably suspect your flywheel may be a bit oversized, having a slightly larger diameter then the system was designed for. Or when the drilled and tapped the holes, they were off a good 1/8" or more from where the holes should have been.

    The newer (89+) high torque starters are a lot smaller and lighter, but the mounting holes will be in the same location. When you get the starter to function, take the time to correct the starter bolt location on the spacer plate with either offset studs, or filling the holes, relocating them to the correct location and drill and tap new holes.

    Otherwise, just think, you will get to do this to every starter you ever put on the motor/trans combo. I wonder how long before the parts stores won't accept your core starters? I sure wouldn't be very happy to get your modified starter housing as a replacement starter when I bought a replacement starter for my old beater. Gene
    Go check that out
    You’ll find this /
    And google mopar starter ring gear 131 teeth
    You’ll find a lot of people have them, don’t know why, others telling them they counted wrong and starter engagement issues.
    Those that report back get cured by going to later model mopar mini starter.
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  3. 31 Vicky gave you some exceptional info there. I checked what I have and 10 tooth bendix and a 131 ring gear is spot on. With the O.D. option of .010 you may do better with the latter starter as mentioned. The 10 tooth Bendix I have is 1.290 O.D. and is second gen starter. What it sounds like and as Squirrel mentioned is the Index boss to help with dial in of the 2 items. All Mopar bellhousings have them see photos. Your 700-R does not.
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    Dino 64, lothiandon1940 and Just Gary like this.
  4. Agreed. I also talked with @19Eddy30 on the phone.
    I'm weighing my technical options, calendar, & checkbook right now.
  5. As a test, I would remove the cover from the selenoid and use my hand to engage it to the flywheel. It should slid in easily and the spring should retract it. When ever I have had a starter that the drive would not retract, it didn't have enough clearance or was crooked such as a chevy with block mount bolts. You're close, just not quite there. Don't loose patience. :)
    Dino 64 and Just Gary like this.
  6. Dennis D
    Joined: May 2, 2009
    Posts: 791

    Dennis D

    I have had them do this to me in the past. Mine would always disengage when the engine started. Talking SBC here though.
    Just Gary likes this.
  7. Joe H
    Joined: Feb 10, 2008
    Posts: 1,096

    Joe H

    Try this, have the starter turn the engine over, then turn the ring gear by hand in the same direction as the starter did. Does the starter retract once you removed tension off the teeth? The force of a running engine should really help the starter disengage.
    Just Gary likes this.
  8. I have mentioned Back Lash several times. That is not front to back space nor to deep in the bottom of the gears causing bind. That is side to side between the 2 items. Without that item, "Back Lash" you have a problem!
    Desoto291Hemi and Just Gary like this.
    The problem wasn't radial clearance (measured with a paperclip). It was axial clearance.:confused:

    @oj emphasized to me that the two gears should only overlap about half the ring gear width, so I added fender washer "shims" until that was achieved.

    Now when I stop cranking, the pinion retracts from the ring gear ~90% of the time. The 10% when it doesn't, a hand-tug on the flexplate pops it loose.

    The washers are a TEMPORARY SOLUTION- long enough to startup the engine & ensure the transmission functions. When I blow the car apart for bodywork & paint, I'll replace them with a solid spacer and press-in new longer studs so the nuts & lockwashers have full engagement.

    BTW, I bought a PowerMaster high torque starter (#9300) just in case mine had a bad solenoid. Same results with it as with my rebuilt stocker, but without having to grind out the mounting holes.:rolleyes: I'll keep it on the shelf for later.

    Thanks, everyone, for your comments & advice.:cool:

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