Starter Mechanism
 

Thought you all might like to see what I found when I disassembled my starter. I have read many threads that mention the possibility of a 12 volt system breaking starter parts. Do you think this is what happened in this case? I have installed a modern starter gear.

Re: Starter Mechanism
 

is yours 12v?

Re: Starter Mechanism
 

I've run a couple of our model As on 12 volts for years with original starter with no problems .

Re: Starter Mechanism
 

it was a common part to break, a repair part was sold

Re: Starter Mechanism
 

Yes, mine is 12 volt.

Re: Starter Mechanism
 

This can happen with 6 volt ..............if the timing isn't retarded on starting! That lever on the left side of the steering column. Or if the base timing is to advanced.

Doug I've been reading your past post trying to help your problem with Trudy on you first 15 mile drive. I'am thinking Trudy's black goo coming from the plugs is due to improper operation of the engine controls. I will suggest getting an owners manual for operating your A, I purchased a repop Ford Model "A" instruction book for a little $ ! Enjoy driving Trudy !

Re: Starter Mechanism
 

I have several aircraft engine starters that were broken apart due to engine kick back. The aircraft have a starting aid that allows for retarded ignition timing of one or both magnetos for starting but now and then the starting aid or aids will die and cause kick back.

The term Ford fracture was coined from people who didn't retard the timing for one reason or another and the hand crank will give them the jolt of a lifetime if they aren't taking precautions against possible kick back.

Starter Mechanism
 

Here is a link to the Ford Model A owners manual (also known as Instruction Book). It’s nice that this is available online. It’s been handy to read on my phone.

http://www.palmbeachas.com/Model-A-I...ion-Manual.pdf


Sent from my iPhone using Tapatalk

Re: Starter Mechanism
 

The torque of a 6 volt starter operated on 12 volts can be reduced by installing a set of 12 volt field coils, see https://www.snydersantiqueauto.com/P...odel-a/starter. You will need a heavy duty soldering iron and maybe new brushes and contact button plus insulators. The pole screws may need to be removed with a drift and large hammer but you will need new screws.

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I've converted several starters to 12 volts for myself and others by reconfiguring the original field coils. When you see what is involved, it's not that difficult.

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Is this a round engine thing? All the Lycomings and Continentals I've flown didn't have anything like that cockpit controllable. I did have a mechanic one day show me the "spring wound rewind starter" aspect of the magneto at start to get a good spark at low rpm.


Maybe we should placard the crank handle with "No crank without spark retarded"

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And yet the Model B engine with 19 degrees of initial advance was supplied with a starting crank. I have had several guys tell me that they have started such an engine with the crank without kickback.

Re: Starter Mechanism
 

[QUOTE=Mister Moose;1958006]Is this a round engine thing? All the Lycomings and Continentals I've flown didn't have anything like that cockpit controllable.

None of them are controllable other than operating the starter. Some of the smaller aircraft engines used impulse couplings that delay the spark during cranking then become non functional after start up due to flyweight action.

The electrical types used in older large engines, including many large radial engines and many newer and more modern opposed engines, produce a shower of sparks through the magneto coil until the opererator lets off the starter at which time the magnetos start to operate at full advance. The TCM/Bendix shower of sparks and the Slickstart starting aids only function when the starter is engaged.

No aircraft magnetoes that I'm aware of, have any mechanical spark control adjustment since it would require that the whole magneto be rotated to make it work. This type of set up is not practical from a reliability standpoint. Aviation systems must be as reliable as possible or they would never be approved for use. Magnetos have to be firmly affixed or the vibration would cause premature wear on the mounting parts.

A battery ignition system doesn't have to rely on the internal timing of the rotating magnet to the opening of the breaker points like a magneto does.

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Impulse couplings, for those who don't know, have a spring inside that winds up against a stop. After a few degrees the stop lets go so that the spring makes the magneto spin fast enough to produce a hot spark. It also has the effect of delaying the spark so that it is not advanced. After the engine starts the coupling disables the stop so that the magneto has the normal advance. The stop is controlled by centrifugal force which increases with higher rpm.

Re: Starter Mechanism
 

I just competed a rebuild of my starter. I put the 12 volt field windings in it a couple of weeks ago but at that time I did not have the parts to rebuild the Bendix or new brushes. I put the new brushes in and put a modern Bendix in. I found a broken starter drive sleeve like the one that broke in Doug's starter, who started this discussion. I have been careful to retard the spark on starting but the starter was operated on 12 volts with the 6 volt field windings for a while before I got the car. I know the starter drive sleeve can break in a stock 6 volt system but I think that running a 6 volt starter on 12 volts will exacerbate the problem.

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if you have a couple of 6v starters available you can mix field coils and make twp 12v starters.

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Actually you don't need two starters. If you are handy with a soldering iron and have some copper strap you can change the field windings of a 6 volt starter to 12 volts. The 6 volt starter fields are two parallel and two series. The 12 starter fields are all in series. If you want to build a 3 volt starter, you can wire all the fields in parallel.

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Thanks Big Hammer. I am running a Zipper dis so there is no spark advance linkage from the steering column. However, another member suggested that I might want to retard the initial Zipper timing, perhaps achieving the same thing.

Re: Starter Mechanism
 

You know that rule about exceptions?

It sounds like you're an A&P, so you might like this.

I flew for a while for an outfit that had several Aztecs. One day while VFR (Thank you very much) over water and about 10 miles out on a long final, the airplane surges with severe yaw. Oh, God, and just as the tattooed on your eyelids engine out checklist comes to life, another surge and we're back to balanced thrust. In 20 seconds another surge, and back again to normal. Then it was constant, in and out, repeating over and over. WTF??? So after about 6 cycles I decided I didn't like it very much, and pulled a throttle to see which one made it go away. Right one. OK. I don't know what in the world is going on, but this engine is going to idle until I'm on the ground. From there not too big a deal, sort of a short strip single engine, plant it, taxi, offload passengers, call the chief pilot. (Not a single passenger asked a question)

Wait for the company airplane, mechanic tears into it. Turns out this Lycoming series was built with both mags on the same gearcase cover. The cover bolts had come loose, but not completely out. However the cover could hang just far enough out so the gears came out of mesh. What was happening was the gears were meshing in and out, and when they were in sometimes they were out of time and produce no power, and when they were in sometimes they were in time you'd get full thrust.

So yeah, redundancy, until all of a sudden there isn't any redundancy anymore.