The Ford Barn

1965 Mustang · 12-20-2022, 05:50 PM

My 29A has the world's crappiest starter motor, which in turn has made my A the most unreliable car I have ever owned. I have owned a lot of ancient cars. After replacing the brushes, the starter drive and additionally the switch several times. I have been able to keep it working for a while before something else goes wrong. It's latest trick is for the starter drive to jam. If I remove the starter and reinstall it ,it is good for a half dozen starts. I drive the car less than once a month. I should probably give up and just spend the several hundred dollars for a completely new starter with drive and switch. Is there any way to keep the drive from jamming (ie: a thick gasket to act as a spacer or something at the mounting opening?). Thanks
(Sometimes if I put the transmission in gear and rock the car the flywheel will un jam)

nkaminar · 12-20-2022, 05:58 PM

Try the modern Bendix drives. There are good and bad quality modern drives. I had to buy a couple from different vendors to find one that I liked and sent the other one back.

Below is a link to one that is out of stock. But it will give you an idea of what to look for.

https://modelastore.com/electrical/s...roduct_id=4110

Gary WA · 12-20-2022, 06:44 PM

Does your flywheel have teeth missing or bad shape? or do you have to long of a bolt in the starter?

rotorwrench · 12-20-2022, 07:42 PM

There are several things that can cause jamming of the bendix. A common thing is if the operator engages the starter and then mometarily lets off the foot switch and then pushes it again with the starter still turning. It's best to engage the starter and keep it engaged till the engine starts or till the start attempt is aborted. Let the starter come to a stop before attempting another start.

Flywheel housing alignment being out of whack can put a strain on the starter as well as the transmission.

Forgetting to retard the spark and getting a strong kick back can bend the starter armature shaft which will create problems.

Get the best quality bendix you can when purchasing a new one. They come with a light pressure spring that helps free the bendix if a start is aborted. The spring being light duty can be damaged over time and be no help at all.

A gasket on the starter isn't always needed. It may put the bendix gear too close to the ring but it depends on the dimensions. If it engaged farther away from the ring gear then a shim gasket will put it closer. This is one of those things that folks don't often check since you can't see what's going on in there unless the bell housing is removed.

1965 Mustang · 12-20-2022, 07:43 PM

I suppose if the flywheel was slightly loose or bent, or teeth were burred or bent it could cause problems. Missing teeth would be likely for the pinion to spin free but not jam, I believe.

Marshall V. Daut · 12-20-2022, 07:49 PM

Sponsored Links (Register now to hide all advertisements)

If this locking-up condition occurs often, then the starter shaft is undoubtedly bent. This happens over time when people forget to retard the spark lever while attempting to start the engine. Depending upon how the initial ignition timing is set inside the distributor, it may too far advanced so that the engine "kicks" back when it catches and jams against the starter's shaft. Enough of these incidents and the shaft will bend, causing what you are experiencing.
To check the shaft, remove the starter (again!) and Bendix drive. Hook the starter up to a 6 volt battery or heavy-duty charger (not a trickle charger or to a battery tender) via jumper cables. It won't matter how you orient the cables, although for consistency's sake the red cable should be attached from the battery's positive terminal to one of the starter's mounting ears as a ground. Connect the black jumper cable to the battery's negative post and touch the other end against the broad brass terminal on the starter. Once connected in this manner, the starter will turn over a high rate of speed. The shaft should spin straight and clean, but if it looks fuzzy and out of focus, the shaft is bent. You can straighten the shaft in a vise or replace the armature. Be sure to hold onto the starter firmly when testing it this way because it will want to take off across the floor from the spinning torque created by the applied juice.
As stated in a previous post, you will probably discover chipped or missing flywheel teeth because the Model A engine tends to come to rest in one of two positions 90% of the time (an estimate) when it is stopped. That means, the starter drive bangs at high velocity against those same two sections of ring gear teeth 90% of the time, usually 180 degrees apart. Eventually that will grind the teeth away, effectively making it more difficult for the Bendix drive to engage the teeth to turn the engine. Not much you can do to permanently fix that short of pulling the engine and flywheel and then replacing the ring gear, or as some guys do, heat the ring gear and rotate it 1/4 of turn to present a new set of unused ring gear teeth to the Bendix drive. A lot of work and expensive acetylene gas just to save $20, though. In the meantime, you can "trick" your engine and instead of letting the crankshaft come to rest where it wants to, keep the car in 1st gear, push down on the brake and slowly let out the clutch. The engine will die. Then be sure to turn off the ignition key. You are basically killing the engine in an unnatural place so that the crankshaft will usually end up in a different place than it normally would on its own. This places the Bendix drive against undamaged teeth. Don't abuse the engine too much this way until you can fix the problem. It's just a temporary way around this irritating problem.
The final ad hoc thing you can do until the ring gear can be replaced is to use the hand crank to rotate the crankshaft a few degrees the next time you are ready to start the engine. Once again, this will put an unused batch of ring gear teeth in alignment with the Bendix drive. It won't help, however, if the starter shaft is bent. Aside from weak operation, you may be facing two additional problems with this starter: a bent shaft and damaged ring gear teeth.
All of these suggestions do not obviate the need to re-straighten the starter's shaft and replace the damaged ring gear. They will just get you through some rough times and potentially embarrassing moments until you can make permanent repairs.
Marshall

Marshall V. Daut · 12-20-2022, 07:50 PM

"rotorwrench" types faster than I do and uses fewer words, but we basically said the same thing.

M.

1965 Mustang · 12-20-2022, 08:02 PM

Thanks for the input, I will check the end of the armature shaft . Maybe I will even get fancy and us a dial indicator on it. I don't look forward to replacing the flywheel or ring gear though. Regarding the armature if the bushings were worn the shaft might flop around and cause problems?

Gary WA · 12-20-2022, 08:14 PM

Quote:

Originally Posted by 1965 Mustang

Thanks for the input, I will check the end of the armature shaft . Maybe I will even get fancy and us a dial indicator on it. I don't look forward to replacing the flywheel or ring gear though. Regarding the armature if the bushings were worn the shaft might flop around and cause problems?

also look for cracks on the bendix drive sleeve? while you have it out

CWPASADENA · 12-20-2022, 08:20 PM

If the starter does "lock up", often you can get it to free up by putting the car in 3rd gear and rocking the car backward. Usually, it will pop loose a save you from having to remove it.

My experience,

Chris W.

Pete · 12-20-2022, 08:39 PM

Get one of these and your worries are over, assuming your flywheel gear teeth are in good shape.
https://drivenman.com/product/high-t...-volt-version/

Synchro909 · 12-20-2022, 08:48 PM

Quote:

Originally Posted by nkaminar

Try the modern Bendix drives. There are good and bad quality modern drives. I had to buy a couple from different vendors to find one that I liked and sent the other one back.

Below is a link to one that is out of stock. But it will give you an idea of what to look for.

https://modelastore.com/electrical/s...roduct_id=4110

My experience is NEVER buy one of those "modern" drives. They are not designed for the Model A and only engage the teeth on the ring gear to about half depth. The original style is MUCH better - and cheaper
Back to the OP. does the starter have a 1/2" or 5/8" shaft. Either way (especially with the 1/2") the shaft may be bent. Take the starter out and turn the armature while watching the shaft for straightness and straighten it if it is bent. I bet it is..
If the starter and ring gear are in good order, it should be as reliable as any other.

Joe K · 12-20-2022, 10:07 PM

Flywheel ring gears typically wear at two places - 180 degrees apart. This being where the compression of the engine "stops" the engine when it is turned off, and hence where the starter bendix initially engages the gear. If the engine is "moved" from where it stops about 90 degrees, starting will be likely be "like original."

A solution "in the day" was to remove the worn ring gear, and "turn" it to the next 90 degree position and replace it. Today, given a supply of ring gears readily available, it makes more sense to simply replace the ring gear entirely.

It's not that hard with the flywheel removed. A punch or drift can be used with a hammer to circumferentially "walk" the ring gear off from its seat. The new gear is usually heated in a stove on "self clean" mode (i.e. 500F plus) and the flywheel itself cooled in a freezer. Under this temperature differential, the ring gear will pretty much "drop" into place.

But getting to this point is the work.

Joe K

Charlie Stephens · 12-21-2022, 01:45 PM

Put a hand crank under the seat or park on a hill. If the engine is in good shape it should start easily.

Charlie Stephens

Herb Concord Ca · 12-21-2022, 05:24 PM

If you do decide to remove the starter, Remove the brush end plate, and clean the commutator with solvent then with fine sandpaper. Clean the brush sides and brush holders with solvent then install the starter, it should turn a lot faster.

12-20-2022, 05:50 PM	#1
1965 Mustang Member Join Date: Aug 2013 Location: Rochester WA Posts: 34	Starter Motors My 29A has the world's crappiest starter motor, which in turn has made my A the most unreliable car I have ever owned. I have owned a lot of ancient cars. After replacing the brushes, the starter drive and additionally the switch several times. I have been able to keep it working for a while before something else goes wrong. It's latest trick is for the starter drive to jam. If I remove the starter and reinstall it ,it is good for a half dozen starts. I drive the car less than once a month. I should probably give up and just spend the several hundred dollars for a completely new starter with drive and switch. Is there any way to keep the drive from jamming (ie: a thick gasket to act as a spacer or something at the mounting opening?). Thanks (Sometimes if I put the transmission in gear and rock the car the flywheel will un jam) Last edited by 1965 Mustang; 12-20-2022 at 05:57 PM.

12-20-2022, 05:58 PM	#2
nkaminar Senior Member Join Date: Jan 2012 Location: Western North Carolina Posts: 4,086	Re: Starter Motors Try the modern Bendix drives. There are good and bad quality modern drives. I had to buy a couple from different vendors to find one that I liked and sent the other one back. Below is a link to one that is out of stock. But it will give you an idea of what to look for. https://modelastore.com/electrical/s...roduct_id=4110 __________________ A is for apple, green as the sky. Step on the gas, for tomorrow I die. Forget the brakes, they really don't work. The clutch always sticks, and starts with a jerk. My car grows red hair, and flies through the air. Driving's a blast, a blast from the past. Last edited by nkaminar; 12-20-2022 at 06:04 PM.

12-20-2022, 06:44 PM	#3
Gary WA Senior Member Join Date: May 2010 Location: Clinton,WA/Whidbey Island Posts: 4,170	Re: Starter Motors Does your flywheel have teeth missing or bad shape? or do you have to long of a bolt in the starter? __________________ www.whidbeymodelaclub.com

12-20-2022, 07:42 PM	#4
rotorwrench Senior Member Join Date: Jun 2010 Location: San Antonio, Texas Posts: 16,522	Re: Starter Motors There are several things that can cause jamming of the bendix. A common thing is if the operator engages the starter and then mometarily lets off the foot switch and then pushes it again with the starter still turning. It's best to engage the starter and keep it engaged till the engine starts or till the start attempt is aborted. Let the starter come to a stop before attempting another start. Flywheel housing alignment being out of whack can put a strain on the starter as well as the transmission. Forgetting to retard the spark and getting a strong kick back can bend the starter armature shaft which will create problems. Get the best quality bendix you can when purchasing a new one. They come with a light pressure spring that helps free the bendix if a start is aborted. The spring being light duty can be damaged over time and be no help at all. A gasket on the starter isn't always needed. It may put the bendix gear too close to the ring but it depends on the dimensions. If it engaged farther away from the ring gear then a shim gasket will put it closer. This is one of those things that folks don't often check since you can't see what's going on in there unless the bell housing is removed.

12-20-2022, 07:43 PM	#5
1965 Mustang Member Join Date: Aug 2013 Location: Rochester WA Posts: 34	Re: Starter Motors I suppose if the flywheel was slightly loose or bent, or teeth were burred or bent it could cause problems. Missing teeth would be likely for the pinion to spin free but not jam, I believe.

12-20-2022, 07:49 PM	#6
Marshall V. Daut Senior Member Join Date: Apr 2011 Location: Davenport, Iowa Posts: 2,162	Re: Starter Motors Sponsored Links (Register now to hide all advertisements) If this locking-up condition occurs often, then the starter shaft is undoubtedly bent. This happens over time when people forget to retard the spark lever while attempting to start the engine. Depending upon how the initial ignition timing is set inside the distributor, it may too far advanced so that the engine "kicks" back when it catches and jams against the starter's shaft. Enough of these incidents and the shaft will bend, causing what you are experiencing. To check the shaft, remove the starter (again!) and Bendix drive. Hook the starter up to a 6 volt battery or heavy-duty charger (not a trickle charger or to a battery tender) via jumper cables. It won't matter how you orient the cables, although for consistency's sake the red cable should be attached from the battery's positive terminal to one of the starter's mounting ears as a ground. Connect the black jumper cable to the battery's negative post and touch the other end against the broad brass terminal on the starter. Once connected in this manner, the starter will turn over a high rate of speed. The shaft should spin straight and clean, but if it looks fuzzy and out of focus, the shaft is bent. You can straighten the shaft in a vise or replace the armature. Be sure to hold onto the starter firmly when testing it this way because it will want to take off across the floor from the spinning torque created by the applied juice. As stated in a previous post, you will probably discover chipped or missing flywheel teeth because the Model A engine tends to come to rest in one of two positions 90% of the time (an estimate) when it is stopped. That means, the starter drive bangs at high velocity against those same two sections of ring gear teeth 90% of the time, usually 180 degrees apart. Eventually that will grind the teeth away, effectively making it more difficult for the Bendix drive to engage the teeth to turn the engine. Not much you can do to permanently fix that short of pulling the engine and flywheel and then replacing the ring gear, or as some guys do, heat the ring gear and rotate it 1/4 of turn to present a new set of unused ring gear teeth to the Bendix drive. A lot of work and expensive acetylene gas just to save $20, though. In the meantime, you can "trick" your engine and instead of letting the crankshaft come to rest where it wants to, keep the car in 1st gear, push down on the brake and slowly let out the clutch. The engine will die. Then be sure to turn off the ignition key. You are basically killing the engine in an unnatural place so that the crankshaft will usually end up in a different place than it normally would on its own. This places the Bendix drive against undamaged teeth. Don't abuse the engine too much this way until you can fix the problem. It's just a temporary way around this irritating problem. The final ad hoc thing you can do until the ring gear can be replaced is to use the hand crank to rotate the crankshaft a few degrees the next time you are ready to start the engine. Once again, this will put an unused batch of ring gear teeth in alignment with the Bendix drive. It won't help, however, if the starter shaft is bent. Aside from weak operation, you may be facing two additional problems with this starter: a bent shaft and damaged ring gear teeth. All of these suggestions do not obviate the need to re-straighten the starter's shaft and replace the damaged ring gear. They will just get you through some rough times and potentially embarrassing moments until you can make permanent repairs. Marshall

12-20-2022, 07:50 PM	#7
Marshall V. Daut Senior Member Join Date: Apr 2011 Location: Davenport, Iowa Posts: 2,162	Re: Starter Motors "rotorwrench" types faster than I do and uses fewer words, but we basically said the same thing. M.

12-20-2022, 08:02 PM	#8
1965 Mustang Member Join Date: Aug 2013 Location: Rochester WA Posts: 34	Re: Starter Motors Thanks for the input, I will check the end of the armature shaft . Maybe I will even get fancy and us a dial indicator on it. I don't look forward to replacing the flywheel or ring gear though. Regarding the armature if the bushings were worn the shaft might flop around and cause problems?

12-20-2022, 08:20 PM	#10
CWPASADENA Senior Member Join Date: May 2010 Location: PASADENA, CA Posts: 1,893	Re: Starter Motors If the starter does "lock up", often you can get it to free up by putting the car in 3rd gear and rocking the car backward. Usually, it will pop loose a save you from having to remove it. My experience, Chris W.

12-20-2022, 08:39 PM	#11
Pete BANNED Join Date: May 2010 Location: Wa. Posts: 5,423	Re: Starter Motors Get one of these and your worries are over, assuming your flywheel gear teeth are in good shape. https://drivenman.com/product/high-t...-volt-version/

12-20-2022, 10:07 PM	#13
Joe K Senior Member Join Date: Jul 2010 Location: Cow Hampshire Posts: 4,188	Re: Starter Motors Flywheel ring gears typically wear at two places - 180 degrees apart. This being where the compression of the engine "stops" the engine when it is turned off, and hence where the starter bendix initially engages the gear. If the engine is "moved" from where it stops about 90 degrees, starting will be likely be "like original." A solution "in the day" was to remove the worn ring gear, and "turn" it to the next 90 degree position and replace it. Today, given a supply of ring gears readily available, it makes more sense to simply replace the ring gear entirely. It's not that hard with the flywheel removed. A punch or drift can be used with a hammer to circumferentially "walk" the ring gear off from its seat. The new gear is usually heated in a stove on "self clean" mode (i.e. 500F plus) and the flywheel itself cooled in a freezer. Under this temperature differential, the ring gear will pretty much "drop" into place. But getting to this point is the work. Joe K __________________ Shudda kept the horse.

12-21-2022, 01:45 PM	#14
Charlie Stephens Senior Member Join Date: May 2010 Location: Southern California Posts: 7,066	Re: Starter Motors Put a hand crank under the seat or park on a hill. If the engine is in good shape it should start easily. Charlie Stephens

12-21-2022, 05:24 PM	#15
Herb Concord Ca Senior Member Join Date: May 2010 Location: Concord CA Posts: 652	Re: Starter Motors If you do decide to remove the starter, Remove the brush end plate, and clean the commutator with solvent then with fine sandpaper. Clean the brush sides and brush holders with solvent then install the starter, it should turn a lot faster.