Bendix Drive Question??
 

anyone seen this type of bendix drive? Pros/Cons compared to exposed spring?

Re: Bendix Drive Question??
 

That is the "tractor" drive. They are supposed to be an improvement in reliability over the original Bendix. I am using one though have broken a couple so carry a spare Bendix, just in case. The current has held up for 20,000 miles, so far so good.

A's Always
Dave

Re: Bendix Drive Question??
 

Those modern style drives don't engage the ring gear to full depth but I still have a couple in my cars. I considered making a plate to hold the starter back about 3 mm but that would have meant the pinion was very close tot he ring gear when it was disengaged. I left it alone in the long run.

Re: Bendix Drive Question??
 

Thanks for the feedback as I had not seen one before

Re: Bendix Drive Question??
 

I have one in my car and like it. The old Bendix came out in pieces. I have a starter with 12 volt field coils and a 12 volt battery. The "modern" drive is a little harsher than the original one, but more durable.

Re: Bendix Drive Question??
 

Back about 8-10 years ago, some of these drives were made in India and were junk. I had one that lasted 10 starts.
The one's today are great, especially if you converted to 12 volts.

Re: Bendix Drive Question??
 

Yup,the new ones should have a USA sticker. I just installed one for a friend a few months ago.

John

Re: Bendix Drive Question??
 

The modern drive is far superior to the Bendix in my opinion. I was feed-up with Bendix drive units flying apart, so I made the conversion to modern starter drives in both of my Model A's. Both modern drives have been flawless taking extra stress from the original starters running with 12V. Both of my modern drives came from Bratton's.

Re: Bendix Drive Question??
 

I have had many problems with both Indian made drives and recently a Weldon USA one.
The problem is shown in the pics attached of two starters side by side with standard bendix and Weldon barrel drive in retracted and engaged positions.
The steel ruler shows how the bendix pinion comes about 1/8 inch past full engagement with the ring gear teeth, whereas the barrel pinion sits about 1/2 inch further back from this position when fully extended. It engages only about half the ring rear teeth and would need at least 3/16 of starter shims behind the starter to bring it forward and fully into mesh. This of course is impossible and the starter face locating spigot itself is only about 1/8 high. You can clearly see the partial-engagement wear pattern on the barrel drive photo.
The other factor is that, fully extended, the bendix pinion hits the front collar which in turn is abutted to the bush in the mating face of the starter. So there is a solid immovable stop as the pinion throws forward upon starting.
On the other hand the barrel pinion flies forward, with more gap to accelerate and gain velocity, until it is arrested by the thin cast collar on the root of the helix. It hits this hard enough in the case of the very thin casting on the Indian barrel drives to fracture it under tension. And in the case of the Weldon USA drive it jams in the forward engaged position and the engine then turns it at huge speed! Plus something happens to both Indian and Weldon at the rubber buffer end and the washer covering the grub screw becomes impossible to retract since the inside washer will not contract the rubber inside the dished cover,
Even a few tons on a press will not retract it, so the only redress is to saw the washer in half to get the grub screw out so the drive can be pushed forward on the shafts to get the woodruff key out. See the Weldon photo showing this.
Between David Mossman and I we have destroyed 4 Indian-made ones and 2 Weldons, all on 6 volt starters.
And the partial engagement and higher velocity of engagement does not do the ring gear teeth much good. And 3 of us, Terry Costello too, have jolted our ring gears forward on the flywheel. Possibly because they are made oversize and heat shrinking and loctite does not hold them in place tightly enough.
I do read others have broken or jammed them like we have. Terry Burtz a while ago wrote up an analysis showing the lack of full engagement.
I have just put back on a 5/16-bolts bendix and it starts quietly and gently, unlike the barrel drives which go in with quite a bang. Roadster and Tudor have high compression and static timing is set at 5 to 7 degrees after TDC, for more gentle starting. They are never started with the advance lever down from the stop.
Some say they have never broken a barrel drive, but irrespective of that the partial engagement that is engineered in because they were not designed for the Model A engine, but for tractors, is something I do not care to accept.
SAJ in NZ

Re: Bendix Drive Question??
 

The "modern" drive that I put in has an additional extension after the initial engagement. This a spring loaded engagement and would not be included by simply running the gear to the end of its non spring loaded travel. My drive came with the car so I don't have a history or manufacturer information. Other drives may be different.

Re: Bendix Drive Question??
 

I have one from Brattons and it has worked great for a couple of years.

Re: Bendix Drive Question??
 

Nkaminar, did you by any chance photograph your modern drive before you put it in? I would like to get one like you have, but do not see such available anywhere.
I have broken the slotted collar on the end of a standard bendix, which is why I changed our cars to barrel drives.
Re-cutting a new woodruff slot and drilling a new retaining screw hole 3/16 closer to the starter might be a solution for the Weldon with beefier helix teeth, but the fine-toothed Indian ones are too brittle for my liking. On both types the rubber end buffer mechanism jammed immovably inside the metal housing so the retaining screw could not be undone. A positive stop against the starter end plate rather than internally inside the drive might prevent this too.
The only springs inside my drives were the tiny ones providing friction on the helixes.
SAJ in NZ

Re: Bendix Drive Question??
 

SAJ,

I did not take a photo but it is likely the one available from Snyders, item A-11350-M. See https://www.snydersantiqueauto.com/P...odel-a/starter
The guy I bought the car from shopped at Snyders.

I am happy with the drive but your comments scared me and I ordered a spare from Snyders.

Re: Bendix Drive Question??
 

Nkaminar, you show the USA ones that we are breakiing. They come from Snyders. The Indian made ones are even more fragile.
That Snyders barrel drive is what is in my photos. There is no spring in them for extra engagement. They top out just as I show, coming to an abrupt stop against the end of the helical gear, which breaks off on the Indian ones or distorts and jams thhe teeth into the ring gear on the USA ones. And both types only give partial engagement of the ring gear teeth as I show.
SAJ in NZ

Re: Bendix Drive Question??
 

SAJ,

If the rear crankshaft thrust is in the correct position and not worn, the starter motor does not have excessive end play, and all other parts are at nominal dimensions, the barrel drive pinion misses full engagement by 5/32 (.156) inch.

Terry Burtz

Re: Bendix Drive Question??
 

Thanks Terry. Even a 5/32 spacer would prevent the starter spigot from centralising in the flywheel cover register, meaning only the 3 bolts would hold it central. Are they "fitted" bolts i wonder?
My vernier caliper photos show a difference in engaged position of about 0.352 inch (only set up by eye) but my bendix passes right through the ring gear by about 1/8th.
Cutting a new woodruff slot and screw hole as you suggested elsewhere would be a solution if one was determined to use the barrel-type, as long as a positive stop for the gear against the starter plate prevented jamming on the helices. The Indian ones fly apart when broken so one can see how the end of the cast gear broke away, but the Weldon USA ones remain intact and I have not disassembled a jammed one to see what happened. The inner circlip has nothing to grip on to remove it and Dave Mossman and I gave up in the end.
Dave sends his regards to you too. We are following your new engine with huge interest here in NZ.
SAJ in NZ

Re: Bendix Drive Question??
 

Thanks for the report Stuart. I have put on over 120K mile on my model A and during that time I have had one spring break and one bolt fall out. I don't think that is all that bad for the miles traveled, so I'll stick with the stock bendix.

Re: Bendix Drive Question??
 

Who supplies the Weldon USA Barrel Drive with the strange looking gear?

I made this correction to original post:
Bendix above should have read Barrel Drive

I have 55,000 miles on a used original Bendix (NOT REPRO) on a 6 volt starter that was on the car when I bought it 1962.

The car had a High Compression 5.2 Police head installed for the whole time and occasionally a Lion III 6.5 head and for a longer period an original Thomas Aluminum 8.25 to 1 head.

The Police head is still on the car today.

I did break one spring a couple of years ago though. It happened in the driveway... I guess one could call that good luck?

Re: Bendix Drive Question??
 

Hi Doug. I hope you and Nan are staying safe from this awful virus. Diane Dave and Karen send their regards too. We will miss you at the Gisborne rally coming up soon.
I have done about 50000 miles with one bendix bolt breakage. I am now using bendixes in both our cars and keeping barrel drives under each seat as get-me -homes. So far I have used them on 3 tours on other members cars for broken bendixes and twice on ours to replace broken Indian barrel drives.
Higher compression seems harder on 6 volt starters. But some 12 volt guys using 6 volt starters say they have had no problems.
Benson, I have not seen a Weldon Bendix, only a Weldon barrel drive, which all the usual suppliers stock I think. Nkaminar showed the link to a Snyders one.
About yours failing in the driveway, Dave Mossman fitted a Weldon one while at the local suppliers and he just told me on the phone the previous one failed after only 50 miles and before he had paid for it! He recently had a USA Weldon one jam in the engaged position and took it apart with an angle grinder in our workshop to get it off the armature shaft. This was apparently my new spare one which we fitted at our rally in Te Anau in the South Island, and it broke in Gisborne a bit over 1000 miles north, while he was organising our next rally in Gisborne. He left the car there and brought the starter back here to investigate.
SAJ in NZ

Re: Bendix Drive Question??
 

SAJ, I bought a spare "barrel" drive from Snyders, and you are right, it is not the same as the one I put on my car. It does not extend once engaged. I asked the previous owner where he got the drive and he thinks it was from Snyders and that perhaps they have changed sources. He thinks he may have another one and I have asked him to take a photo. If I get more information I will post it here.