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Thread: Starter catches 50% of the time

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    Starter catches 50% of the time

    Late TR3 motor with the exposed end on the starter. About 1/2 the time the starter will spin free without engaging the flywheel, the rest of this time it grabs and does a fine job of cranking and starting the car. I had the starter on the bench during the recent re-build and seems to operate as it should, the ring gears are all fine, no missing teeth.

    The only remedy I have tried is to lubricate the end that is visible with some spray lithium grease. Not sure what to try as it is not 100% failure.

    All suggestions appreciated.

    Bill B
    TS75131E

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    Great Pumpkin TR3driver's Avatar
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    Re: Starter catches 50% of the time

    IIRC, the book warns against lubricating the Bendix. It has to be dry to work right.
    I would also clean the battery posts and clamps, plus the connection where the ground strap meets the firewall. Any corrosion or paint can limit current just enough to make the Bendix not work.

    You might also verify that the engine doesn't move at all. If it moves a half turn and then the starter spins free, that's a different problem.
    Last edited by TR3driver; 02-15-2020 at 03:04 AM.

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    Re: Starter catches 50% of the time

    Quote Originally Posted by TR3driver View Post
    IIRC, the book wants against lubricating the Bendix. It has to be dry to work right.
    I would also clean the battery posts and clamps, plus the connection where the ground strap meets the firewall. Any corrosion or paint can limit current just enough to make the Bendix not work.

    You might also verify that the engine doesn't move at all. If it moves a half turn and then the starter spins free, that's a different problem.
    OK, Iíll go back and clean the bendix real good. Donít think the motor moves at all, but will re-check.

    Cables are all new, clean, and tight, all new restoration.
    Thx

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    Re: Starter catches 50% of the time

    It’s also possible that your ring gear has moved.
    Elliot
    Central PA
    1973 TR6 Damson Plum / Biscuit interior, HVDA 5-speed, Good Parts Hubs
    1976 TR6 White/Biscuit interior SOLD
    Nostalgia isn't what it used to be.

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    Re: Starter catches 50% of the time

    I think the Bendix drive gets ample lubrication from the spinning flywheel and extraneous lube from the engine, pilot bearing and throw out bearings. More than likely problem is old oil and dirt restricting movement of the Bendix gear. Your thorough cleaning should take care of it. Douse with ample brake cleaner/carb cleaner and dry off. I have always used a small amount of lubrication...but don't know if it is necessary from what Randall says. He's usually up on those things.

    The Bendix relies on inertia to throw the gear into the flywheel, so anything that restricts movement of the gear or slows the initial rotation of the starter can affect engagement.
    John

    1955 TR2

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    Jedi Knight
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    Re: Starter catches 50% of the time

    [QUOTE=Cables are all new, clean, and tight, all new restoration.
    Thx[/QUOTE]

    Ah, but might there be some nice fresh paint between the cables and the contact surface??
    Charley
    1962 TR4
    1963 TR4
    1959 TR3A A work in progress.

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    Re: Starter catches 50% of the time

    This was a frame off restoration, all connections are clean and tight. Once it catches, it Crankís till it starts.

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    Re: Starter catches 50% of the time

    I had a similar problem once and it turned out to be the cotton wrapping on the field coils was old and rotting. I rewrapped them myself for like 5 bucks. I bought a roll of the cotton tape from general electrical motor repair shop. It took some time, but was easy to accomplish.

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    Re: Starter catches 50% of the time

    Quote Originally Posted by BigCountryBritish View Post
    This was a frame off restoration, all connections are clean and tight. Once it catches, it Crank’s till it starts.
    I've seen it more than once : The ground strap gets bolted to the firewall, which was painted during the restoration. No matter how clean and tight that joint is, it has to be bare metal to bare metal or it doesn't conduct.

    Starter stall current (which is when it spins hard enough to extend the Bendix) is given as roughly 450 amps at only 7 volts; while normal cranking current is only 250 amps at 9 volts. So a tiny amount of resistance can interfere with the jerk that engages the Bendix, but still let it crank the engine.

    Here's the note about not lubing the Bendix:

    Randall
    56 TR3 TS13571L once and future daily driver
    71 Stag LE1473L waiting engine rebuild
    71-72-73 Stag LE2013LBW waiting OD gearbox rebuild

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    Re: Starter catches 50% of the time

    Quote Originally Posted by Gliderman8 View Post
    It’s also possible that your ring gear has moved.
    Shouldn't be an issue here (as it is for later TR6). On a later TR3 through TR4A, the ring gear is bolted to the flywheel.

    And before that, the starter tried to drive the gear further onto the flywheel, against a shoulder (that it should already be up against).

    The problem with the ring gear moving didn't start until they went to a pre-engaged starter design, around 68 or 69. No doubt someone saved a few dollars by not changing the flywheel & ring gear to match the change in starter motion.
    Randall
    56 TR3 TS13571L once and future daily driver
    71 Stag LE1473L waiting engine rebuild
    71-72-73 Stag LE2013LBW waiting OD gearbox rebuild

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    Re: Starter catches 50% of the time

    Quote Originally Posted by TR3driver View Post
    Shouldn't be an issue here (as it is for later TR6). On a later TR3 through TR4A, the ring gear is bolted to the flywheel.

    And before that, the starter tried to drive the gear further onto the flywheel, against a shoulder (that it should already be up against).

    The problem with the ring gear moving didn't start until they went to a pre-engaged starter design, around 68 or 69. No doubt someone saved a few dollars by not changing the flywheel & ring gear to match the change in starter motion.
    Thanks Randall... I didn't know the ring gear was bolted in place.
    I was speaking from experience when I suggested the flywheel might have moved. The same symptoms plagued my car.... starter gear would not engage all the time but it would just spin.
    Here's a pic of my flywheel with the ring gear as it was when I removed it. The ring gear should be against the shoulder at the top of the pic. The ring gear moved almost 2 inches away from the shoulder making it impossible for the starter to engage unless the flywheel was 180 degrees opposite.
    A $30 ring gear but a PITA to install it. All is good now!

    IMG_2087.jpg
    Last edited by Gliderman8; 02-16-2020 at 07:52 AM.
    Elliot
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    1973 TR6 Damson Plum / Biscuit interior, HVDA 5-speed, Good Parts Hubs
    1976 TR6 White/Biscuit interior SOLD
    Nostalgia isn't what it used to be.

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    Re: Starter catches 50% of the time

    Just had a TR4 do me that way. Starter bendix not engaging flywheel but once in about ten tries. I removed starter, installed a thin starter spacer and works everytime now.
    Marv

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