Retrifitting a needle bearing into a generator?

I’m contemplating my next step in resolving my generator malaise. When I pulled apart my freshly rebuilt C42 I found that even after just a few hundred miles the fresh armature had some scoring on the bushing end and there is some wear on the new bushing. I’d left the bushing sitting in oil before installing it and a couple of times used a hypodermic needle to inject some more. It’s just never seemed like a great idea to me to be running a shaft turning at twice the engine speed when there is no constant oiling mechanism and no really good way to ensure that it even reaches the bushing when oiling it manually. The dust seal in the cap is secured by a solid retainer so just injecting oil randomly doesn’t give me much confidence that it’s going to go where it’s needed.

I have a NOS dynamo sitting on the shelf and before sticking it in, I was considering taking one of my spare end brackets and the new armature to a machine shop and having both parts machined to accept a needle bearing instead of a bushing. I found one here that seems like a close fit:

http://www.qbcbearings.com/BuyRFQ/NeedleB_ST_OE_I.php#

BNDSCE-912, would require the shaft be turned down from .59 to .5625, and the hole would need to be opened to .75 from .714. It’s a little shorter than the bush at .75 instead of 1" but I don’t see that being a big problem. From a machining perspective my only concern would be that they are able to bore the hole squarely. There seem to be plenty of meat in the bracket for it to be safely opened up 1/16".

The max speed rating is 18k, although that’s probably for oil. It’s likely a bit lower for grease, but even if it was only 12k, that should be fine for this application. This begs the question, why wouldn’t they just have done this originally? Were they just being cheap, or is this a bad application for a needle bearing due to the load? It would certainly be nice to never have to worry about wear to this part or to the increasingly rare armature.

Hi Erica,

As you know I’m not an engineer so take my thoughts with a large grain of salt. It seems like to me that a bushing should be fine in this application if you could keep it oiled. Would it be possible to drill and tap a fitting into the bushing that would allow you to oil it periodically? Even a zerk fitting that you would remove to squirt a little oil in now and then?
These generators were the bane of Jerry’s E Type, his son even had to replace the generator on the way back to Palo Alto from Missoula and that was Jerry’s brand new unit. Maybe you should think about replacing it with an alternator?
Cheers,
LLynn

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Really?? Sir William, famous for squeezing nickels till the bison shat?

:yum:

Ive made similar mods to other generators, and it appears you are determined to keep thr car as a DC generator. I see no issues with your proposed mods.

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Lynn,

Yup bane of mine also. My first attempt at rebuilding my original resulted in a spun bushing that ruined the original armature. I’ve caught this one before that happened, but it just shouldn’t be this much of a headache. From what I’ve been reading, bushings that have constant running high speed shafts should really have a constant oiler.

I have considered doing exactly what you suggest, drilling a small hole right through the side of the housing and bushing. It can be a teeny hole so dust doesn’t get in and I can inject it right onto the shaft while it’s running. This will be my plan b in case the needle bearing idea isn’t feasible. Annoying to have to oil a generator before every drive but I guess that’s the punishment for driving an antique.

Somewhat determined just because I’ve already invested in several and have a lot of spare parts. The bushing is really the most persistent hassle for me. If that weak spot can be mooted I think I can live with the old school Edison power. Besides I’ve heard that fancy alternating juice is really dangerous. An elephant got electrified by it once.

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I wasn’t aware they used Buffalo Nickels in England. :innocent:

Metaphor, Johnny, culturally-relevant metaphor…:wink:

Hi Erica, I still run the original genny in my '62. I rebuilt it about three years ago. Not sure about this particular bushing but suspect it is sintered bronze. Reading your issues I now realize that I must have been lucky to buy a NOS bushing. It came in a wax bag marked Joseph Lucas Limited. I guess it sat in a shelf for 50 years somewhere. I have run 3000 miles since and have only added oil to the wadding in the little hole on one occasion. Perhaps it might be worth sourcing a short length of good quality “known entity” sintered bronze rod and having a bushing or two machined up? I have another after market bushing that is neither the same colour (under a file) or dimensions (too loose) as the NOS unit I fitted. Note to self -
oil bushing. FWIW, Paul

Having an S3 I was reading through the posts just of sheer interest. I came across something that may be a Queens Englishs vs. American English thing. Maybe vs. down under English ?
Someone mentioned a DC generator. Isn’t that in English (Queens) called a dynamo ? A generator is by default an AC producing device ?
DC - Dynamo
AC = Generator (need a rectifier to work in a DC system, like a car)

From a non native English speaking … Ole

Metaphor maybe, but also a myth in many respects.

We published a story by a former quality inspector from Smirhs Instruments recently. I asked him about Jaguar’s choice of instrument grade, since it is routinely trotted out here that if Arthur Whittaker or William Lyons had spent a little more, they could have had better instruments.

Myth busted. There was no better grade for them to miss out on.

Fast forward twenty years to Sir John Egan, former boss of Unipart who supplied Leyland. He analysed the key quality failing in bought-in components and divided the list of suppliers amongst his most senior managers. He took some of the hardest cases himself and personally spearheaded a quality drive with them.

Again, when discussing it in person, Egan said there was no ‘spend a few nickels more and buy better quality’ argument. He told me Jaguar got no worse thsn anyone else - it was a mixture of ignorance and carelessness that suppliers were accepting low quality output, which only changed when he went to see the CEOs of Lucas et al, to threaten financial woe if their warranty performance didn’t improve.

I do not know the quality of the bushing that Lucas may have used in this generator, but I do believe most other brands such as Delco and Bosch also used a ball bearing on the pulley end and a bushing on the other end.

As to the names, like with most parts, everyone seems to use their own name. I do not believe there is a “standard.” Most of us in the USA call the “alternator” and “alternator.” (I know, stupid sentence!) But I always found it interesting GM/Delco always called the “alternator” a “generator.”
Tom

An alternator is a generator: a generator is a generator. One does it differently than the other.

This is one of thise areas of pedantry, up with which I just shrug my shoulders!

The Lucas C45PVS “Special Equipment” generators supplied to the XK120, XK140, and XK150 had ball bearings at both ends. These generators seem to have held up very well with few serious failure issues. If you can modify a later Lucas generator to use needle bearings instead of the bronze bushing, that might be a very good solution.

Below is a link to a well-researched survey of these “Special Equipment” generators. Starting at Section 4, there is discussion of the ball bearings used at both ends.

http://www.bobine.nl/jaguar/13-electrical/lucas-c45-pvs-special-equipment-generator/

Paul,

For the most part I’ve only ever used the OEM ones. The only exception was after one of the OEM ones bound up and spun and tore hell out of that armature. I had to have that armature turned down to clean it up and a local shop had to use a different bushing. I wish I’d considered a needle bearing at that time. That armature is long gone now though as the commutator bars started to come loose. I have not had good luck with generators.

Interesting, I’d never heard of the special equipment units. I ordered this bearing and will speak with the local shop about installing it. I seems like a pretty close fit.

Hi Ole, I did my electrical enginering degree in the 1980s. Generically called generators but more specifically: AC generation is by alternator; DC generation is by generator. Dynamo is a lessor used term in Australia - probably used more for smaller DC generators. Paul

I will watch this with interest! I have another original generator in my Mk 2. Paul

Ironic that the generator used on bicycles by rubbing on the tyre sidewall was called a dynamo despite being an AC output device!

I do remember those bloody noisy things - so much friction and hopeless in the rain!

hi Erica, you have to limit the lube around the commutator area. the bearing at that end is always an oilite bushing or a double sealed ball bearing (lubed for life) in my experience. use of a high quality replacement should give reasonably long use unless it sees too much heat. i don.t have an e generator to check but there may be some interchange possible for different back end plate as the ball bearing one has a much larger boss. you may want to compare to xk 140/150, mk2, tr3 & etc.