Bendix spring is good, but gear doesn't move on down.

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Model T Ford Forum: Forum 2015: Bendix spring is good, but gear doesn't move on down.
Top of pagePrevious messageNext messageBottom of page Link to this message  By Tony Barchock Canton, Mi on Sunday, March 15, 2015 - 03:25 pm:

Start spins up nice and fast.

Actually have the bendix cover off so I could make sure all was right and tight.

She spins fast but doesn't budge down. If I start the drive gear down a bit it then moves down to the flywheel.

Am I missing an adjustment somewhere?

Thanks


Top of pagePrevious messageNext messageBottom of page Link to this message  By Peter Claverie on Sunday, March 15, 2015 - 04:26 pm:

That's a very coarse and quite loose-fitting thread. The theory is that the gear will move down the screw by sheer inertia - the starter starts to spin quite abruptly, and the gear is trying to not spin.

Conversely, when the engine starts and the flywheel is turning the little gear faster than the starter is turning, it'll walk back up the screw and disengage.

No adjustment -- it is quite reliable IF the threads are clean and there's some oil to make it slide easily.

Best guess - there is some rust, or maybe some band fibers, or some other gunk, in the threads.

Take the bolt out of the Bendix and remove it, and clean everything well. If it's still binding, something is bent. I have no idea how that happened!


Top of pagePrevious messageNext messageBottom of page Link to this message  By Ron Patterson-Nicholasville, Kentucky on Sunday, March 15, 2015 - 04:43 pm:

Tony
Is the counterweight (theory) properly affixed to the drive gear?
1
Ron the Coilman


Top of pagePrevious messageNext messageBottom of page Link to this message  By Harold Schwendeman - Sumner,WA on Sunday, March 15, 2015 - 05:22 pm:

Seems like I remember awhile back that there was a "batch" of bendix units made with some improper machining which cause many of them to "stick". Altho' the bendix in this case does not appear to be very new, is that right?


Top of pagePrevious messageNext messageBottom of page Link to this message  By Norman T. Kling on Sunday, March 15, 2015 - 05:45 pm:

You will notice in the picture to the left is a little spring loaded plunger which rides in the groove when the starter is not in operation. When it starts to spin, the centrifugal force will push the plunger in against the spring and the bendix will move down the thread toward the flywheel. Maybe that plunger is sticking?
Norm


Top of pagePrevious messageNext messageBottom of page Link to this message  By Fastfourt on Sunday, March 15, 2015 - 06:08 pm:

My bendix stuck the grove the pin rides in stuck at the end of travel so I filled the grove and its working for the last two years


Top of pagePrevious messageNext messageBottom of page Link to this message  By Harold Schwendeman - Sumner,WA on Sunday, March 15, 2015 - 06:34 pm:

Fastfourt - That one definitely reminds me of that bad batch of "repop" bendix units from awhile back!


Top of pagePrevious messageNext messageBottom of page Link to this message  By Tony Barchock Canton, Mi on Sunday, March 15, 2015 - 07:17 pm:

Looks like this may be the issue. the plunger rides on top of the screw as opposed to in it.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Ron Patterson-Nicholasville, Kentucky on Sunday, March 15, 2015 - 07:36 pm:

Tony
The "plunger" as you call it is actually the "anti drift Pin". It is supposed to ride on the top of the thread as shown in the photo and when engaged drops into the channel as show by thew arrow in this photo.
1
When the starting motor shaft starts to turn with great torque the counterweight allows the gear to remain stationary on the drive shaft causing it to run on the thread toward the ring gear. When the engine starts the gear is thrown back toward the opposite end and the drift pin falls into the channel shown in red holding it from vibrating back and periodically making contact with the ring gear while the engine is running.
That is how the Bendix drive works, Find out why it is not.
Ron the Coilman


Top of pagePrevious messageNext messageBottom of page Link to this message  By Tony Barchock Canton, Mi on Sunday, March 15, 2015 - 07:47 pm:

hmmmm, when I move the gear a bit down the shaft it spins into the flywheel. But when it is full out it will not engage...

Hmmmmmm


Top of pagePrevious messageNext messageBottom of page Link to this message  By Ron Patterson-Nicholasville, Kentucky on Sunday, March 15, 2015 - 08:14 pm:

Perhaps the drift pin has too much downward spring pressure holding the gear from moving down the shaft. Get the head of the pin into the resting channel and see how much it takes to unlock it and allow it to move.
Ron


Top of pagePrevious messageNext messageBottom of page Link to this message  By David Dewey, N. California on Monday, March 16, 2015 - 12:50 am:

The plunger looks like the problem to me, shouldn't the bottom be a nice smooth round end? That one has some "stuff" on it.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Tony Barchock Canton, Mi on Monday, March 16, 2015 - 09:12 am:

David,
I was squirting oil on it like crazy so that is probably what looks like Stuff.

Thinking about replacing instead of trying to mess with this re-pop

Anyone have a good recommendation for a re-pop or get a used NOS?


Top of pagePrevious messageNext messageBottom of page Link to this message  By Ken Todd, ............Red Deer, Alberta on Monday, March 16, 2015 - 10:37 am:

Never heard of "used NOS" before, that's a new one on me. Either used or NOS, but can't be both.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Tony Barchock Canton, Mi on Monday, March 16, 2015 - 11:06 am:

well I missed a / between the used and nos forgive me sir...


Top of pagePrevious messageNext messageBottom of page Link to this message  By Jerry VanOoteghem - SE Michigan on Monday, March 16, 2015 - 01:22 pm:

Tony,

Some of the reproduction units didn't seem to have the thread cut far back enough, causing the gear to jam on the last little bit of thread and stick. Look in the area of the blue arrows for any signs of the gear having jammed up on the last little bit of thread. Sometimes a little material removal with a die grinder is all it needs.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Tony Barchock Canton, Mi on Saturday, March 21, 2015 - 11:35 am:

Did some oiling and filing and she works.

Thanks again for all the advice!


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