Bendix disengaging early

[99sh]

On cold starts my bendix disengages early after a few engine rotations and free wheels. On the 2nd start attempt the car fires right up. It happens 100% of the time and can't figure out what's going on. I replaced the spring, no change. I even replaced the entire bendix assy from an original starter, also no change. Car runs fine otherwise, I just want it to start and keep cranking on the first try.

I'm still on a 6V system. Thoughts?

[Marshall V. Daut]

The next time that happens, stop after the first attempt. Remove the starter and feel the back of the ring gear teeth accessible through the hole in the flywheel housing where the starter is mounted. If the teeth are chopped away or reduced in thickness, the Bendix drive cannot grab the ring gear enough to spin the crankshaft. It may budge it a little so that when you try the starter a second time and the Bendix drive slams against the ring gear, enough good teeth are now in position for the drive to grab and spin the crankshaft.
The Model A engine has a tendency to stop in one of two places when the ignition is killed. That means the same two places on the ring gear take the most beating from the Bendix drive while the other teeth are rarely engaged. You could try force stopping the engine by holding down the brake pedal and letting out the clutch in third gear. The engine will stall in an unnatural position. If the Bendix drive is able to turn the engine over upon the first attempt to start, then you'll know that the ring gear teeth are bad in those two places where the engine usually stops.
The cure? A LOT of work to either remove the engine or the rear end in order to reach the flywheel to remove it and swap ring gears.
Marshall

[nkaminar]

Examine the teeth on the ring gear as Marshall said. You can turn the engine over with the hand crank to examine all the teeth on the ring gear.

You may want to try a spacer on the starter motor to engage the Bendix gear more on the ring gear, but be careful to make sure it can dis engage by making some measurements. You may also want to try a modern Bendix.

[rotorwrench]

The bendix design was sensitive to kicking out at the slightest rpm above the starter speed. Ford kept this design all the way through the flathead era before finally changing to a sprag clutch type design. If only one cylinder fires it can kick it out. Once more than one cylinder fires then the engine will usually run.

[Ruth]

Originally Posted by nkaminar

You may want to try a spacer on the starter motor to engage the Bendix gear more on the ring gear, but be careful to make sure it can dis engage by making some measurements. You may also want to try a modern Bendix.

Snyder's has Starter shims. https://www.snydersantiqueauto.com/p...id=976163&cat= Ensure you maintain a good ground as the shim is paper. I have never had the need.

[99sh]

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I made an attempt at two things.

1 - Cranked the motor with no ignition/fuel to see if the bendix pops out. Did not. I let it crank for quite a few complete revolutions

2 - I did inspect the ring gear and rotated the crank by hand. From what I can tell it's in pretty good shape.


Sounds like I need to fine tune my ignition advance/fuel/throttle to make it fire on all cylinders at the first attempt. Maybe it is one cylinder "preignition" causing the bendix to kick out.

[Big hammer]

A past friend of mine ( RIP BobDoe ) would crank his a couple of times before turning the key on ! My guess he would reach through the steering wheel with his left arm to turn the key and pull the choke with his right . You might try setting the timing a little later

[nkaminar]

When starting try a little more advance than fully retarded.

[99sh]

Something else worth nothing. When I was cranking the starter with no ign or fuel, there was one very brief moment when a cylinder ignited. Likely some residual fuel enough for a half firing. Whenever I turn off my car I always let the car run with fuel shutoff as the carb drain out.

That all said I'm thinking the bendix is kicking out due to some residual fuel partial firing. I'll try advancing the ign as previously mentioned and running the crank until it's fully dry of fuel.

[Ruth]

Originally Posted by 99sh

Something else worth nothing. When I was cranking the starter with no ign or fuel, there was one very brief moment when a cylinder ignited. Likely some residual fuel enough for a half firing. Whenever I turn off my car I always let the car run with fuel shutoff as the carb drain out.

That all said I'm thinking the bendix is kicking out due to some residual fuel partial firing. I'll try advancing the ign as previously mentioned and running the crank until it's fully dry of fuel.

Not sure how it is firing with no ignition?

[rotorwrench]

The engine would have to be pretty hot to ignite a fuel charge with no ignition on.

[99sh]

Hmm... fair point. Maybe I subconsciously turned the key, I'll try it again later

[Chuck Sea/Tac]

Completely off the topic(well kinda).has anyone started their engine by turning the key on, then retardng the spark? It’s happened to me twice. Kinda surprising. Just happened to have a cylinder close to tdc, and boom!

[Phil Brown]

Originally Posted by Chuck Sea/Tac

Completely off the topic(well kinda).has anyone started their engine by turning the key on, then retardng the spark? It’s happened to me twice. Kinda surprising. Just happened to have a cylinder close to tdc, and boom!

I saw an old timer once use the crank to set the piston just past TDC with the hand crank telling a somewhat long and involved story. Then he walked around to the running board saying " it's the running board, it makes things run" then he jumped up on it bouncing the car and it started.
Old timers always know the neet tricks