Lucas 11AC - bad bearings?

I took a drive to Vancouver B.C. this weekend in my Jag. It was going well, but after my fuel stop to get cheap gas in Bellingham, WA, I noticed an odd noise from the front of the engine - almost sounded like rustling paper at first. I couldn’t hear it with earplugs or earphones in place. It varied with RPM.

It got louder and louder until I could hear it even with plugs in my ears. So I cut the trip short and prayed it would get me home without some major failure. There were no negative indications on the instruments. Shortly after crossing the Canadian-US border, the sound got a lot quieter and stayed that way. I could no longer hear it at freeway speed.

Removing the belt silenced the noise, so I put the belt back on and used a stethoscope. Has to be either the timing chain, jockey pulley, water pump, or alternator, right? Only the alternator had a non-rhythmic sound pattern.

Also the cooling fan and the subframe below the alternator were coated in a fine brown-black dust which I had never noticed before. So I’m pretty sure it’s the alternator, with some mechanical failure. No issue with output the whole time.

Since I doubt my local rebuilder can get the bearings and bushings, etc. for a Lucas 11AC readily, I’ll send it off to TAE in Arizona for a rebuild. In the meantime I ordered a SNG Barratt Lucas reproduction (which I think is a modified Bosch.)

(no desire to switch to a 1 wire - I finally think I understand how the charging system works and better the devil I know than the one I don’t - at least until another 4TR fails!) Also I don’t feel like getting rid of my ammeter and I have all the juice I need even with the stock 45 amp unit. (SNG jumps it to 55 amps which I believe will still be OK for the ammeter and not require a shunt.)

But it looks like I’ll have to transfer the cooling fan over from the original 11AC which I don’t really want to do. The SNG unit pictures don’t show a pulley or fan (I have a spare pulley I bought from Moss last year, but not a fan.) Maybe any generic fan would work?

Dave

Both bearings for the 11ac are available.
Here in Vancouver, Canada, Bridgeport Electric has both.

I suggest you get a garden hose, cut it to four feet length and use it as a stethoscope to find out where the noise is coming from!

I have used this to find a bad jockey pulley bearing as well as a bad front alternator bearing. It is rare that the rear alternator bearing goes as it is under very little load compared to the front

Dennis
69 OTS

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It may not be the bearings. After many miles, the fans can fret at the key, and then they’ll go out of balance. This would be consistent with the dust that you’re seeing.

I can’t visualize that without taking the 11AC apart, but does that mean the fan is toast?

The round fan is one of the distinctions of the 11AC I’d like to preserve, but it sounds like it’s worn. If so, where to get a replacement, if any even exist outside of a chance eBay find? Would a rebuilder like TAC be able to fix it or would they just put on a normal fan (I’ll have to call them to ask.)

I did use a stethoscope, a cheap Harbor Freight item. The only irregular sound came from the alternator body. Front cam covers, head next to front cam cover, water pump body, and jockey pulley bracket (couldn’t probe the spinning pulley itself, naturally) had no odd sounds just whirring.

Spinning the alternator pulley by hand was smooth with no noise, so maybe the tension on the loaded belt pulls the fan into contact?

Thanks,

Dave

They’re hard to find, but they’re out there. They come in CW and CCW versions, so you have to mind that. Once you take the alternator off, it’s easy enough to dismount the fan and inspect the hub. If it’s bad, it may be salvageable, you’ll have to see what you have.

You might be able to confirm whether an alternator bearing is the culprit by switching maximum electrical load on and off, listening for a change in noise. That wouldn’t necessarily rule out the fan, as suggested by Michael, but it could confirm the area.

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A number of years ago I reported a similar effort to nail down an odd noise coming from the area of the alternator. After some time I identified the fan as the culprit. A few of the spot welds holding it together had let go in a row, causing it to vibrate harmonically at certain rpms. It didn’t get to the point where the piece was shifting and wearing into the belt but that was in the offing had additional spot welds broken from metal fatigue. I have a spot welder so it was a simple fix. You can likely confirm this as the cause of your issue by removing the belt and tapping the fan with something hard to see if it rattles.

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That’s a good thought, I’ve seen that too

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Dave,
The alternator fan rotation is such that it sucks cooling air from the alternator rear side (ie back of car) to the front side

Whilst you are in there dump the jockey pulley. It is a source of noise and performs no real purpose given the way we drive our cars. Jaguar put it there so owners would not need to adjust the belt every few thousand miles.

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I didn’t have time to dismantle the alternator or try a full load test, but was able to try grabbing the fan disc at intervals between the fan blades.

At least one segment produced a clicking noise as I wiggled the fan disc fore and aft. Sign of failure? If it’s spot welds I hope the fan is salvageable.

I understand the 11AC shaft is 5/8", so I called the local alternator rebuild shop (who has stacks and stacks of alternators from all eras) to see if he can find me a 5/8" shaft fan with clockwise rotation for cooling. He’s looking now, thinks maybe a Motorola fan blade might do the trick.

Hope he’s got something. Never knew Motorola (if I remember the name he gave correctly) made alternators!

Dave

Dave
A test for alternator bearings is to hold the alternator in one hand and spin it you should feel no vibrations or hear any noise
Any local alternator shop can fix it up , I sure wouldn’t be sending it away . The fan might be problematic
Remember your not alone out there could launch a rescue
Cheers

Jim, I did spin it and it felt fine, no roughness, rattling or otherwise. If it turns out the fan is OK, I’ll talk to my local rebuilder to see if there will be any problem getting bearings. I had read other people who had to work hard to get a set of replacements for the 11AC.

The rebuilder found me a fan to fit a 5/8" (.625") shaft (figure taken from the Coolcat website) with straight blades so I presume it’s omnidirectional.

Concerning me is that the spare C24392 alternator pulley I picked up last winter seems to only measure at .57", so I hope I don’t have a duff repro part/incorrect application here.

Dave

You need a shop that works on commercial type equipment if you goggle alternator repair they’ll show you how to do it yourself easy
Bearing numbers are standard across manufacturing or they use to be and I really doubt the bearings are anything special
When I was young working on motorcycle cranks I’d change the main bearings .the spec for them was to be within limits for 10 hrs

Cheers

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The rear bearing is more likely to be “custom” than the front, but they’re out there:

I also found a disc-type fan said to be for 65-71 E-types:

1965-1971 JAGUAR XKE ALTERNATOR FAN LUCAS | eBay

But, it doesn’t look like mine as the fins project beyond the fan disc. I’ve never seen one like this on a picture of an 11AC. To be honest, it looks like a 11AC disc welded to a conventional-type angled fan blade.

Now my area rebuilder gave me a fan for a 5/8" (.625") shaft. It’s a conventional type and turned out to have angled blades. I believe this is for clockwise rotation if I’m correct that the blades should be angled towards the direction of rotation for the alternator.

It looks almost brand new other than a light coating of dust, the rebuilder said he had a stack of them back on the shelves!

I also matched it up with the reproduction C24392 pulley and the pulley is definetly undersized. The fan came out around .622-.623". The pulley - .585-588". The rebuilder trial fitted it to a 5/8" shaft and it didn’t fit of course. Here’s where I overlaid the two pieces:

So most likely I have another duff reproduction part and will have to pay a machine shop to bore it out correctly.

Dave

Just get a step drill clamp a piece of metal with a center hole to the back and drill

I may have to give that a try! Thanks.

Especially depending on how much I’d be charged to bore the pulley out correctly.

Dave

I was able to remove and dismantle the original 11AC and compare with the reproduction unit.


The reproduction pulley is not as far off as I thought, but it still will not slide onto the alternator shaft of either unit. The old pulley pops on to the new one, and the measured shaft diameters for both units is very close.

Probably it would just take a bit honing to get the new pulley to slide on, but lacking a drill press or other fixture to assure concentricity I’m not sure how I would tackle that. A step drill seems too extreme for such a small clearance, and the diameter of shaft or pulley is not a neat 5/8" (.625") - more like ~.585". Opening the pulley up by maybe .002" might do the job.

As to the real problem - it indeed seems to be the fan so looks like Michael called it. The center keyway for the fan has metal broken off, so likely it was no longer concentric. When I rotated the alternator shaft observing the edge of the fan, it definitely had an eccentric motion visible at the edge of the disc, obscuring the edge of the alternator body as it rotated then revealing it.

The issue is that the fan is scraping the body. Would making sure the fan is centered solve that problem? Note the tips of the fan here:

Then the body of the 11AC and the scraping on the upper left quadrant of the body:

And why the fan isn’t concentric - the fan keyway is damaged. However the rest of the fan is solid - no loose parts or welds, or cracks.

If concentricity is causing the fan interference, I’m not sure how I could fix that. I can’t use the substitute fan from my rebuilder, because note how the Lucas fan is dished in the center. This gives extra clearance for the fan tips, whereas the flat “conventional” fan scrapes the body.

I could flip the fan to use the opposing keyway to the damaged one, but I would need to file it. I don’t think I can use a shim to gain clearance because I think that would also raise the pulley and throw it out of alignment. Given the way the lower mount on the 11AC is designed I don’t see alignment could be done there short of slotting the mount bracket.

Any ideas on how to repair that thin sheet metal keyway? Maybe some TIG welding pro could do it? Or take the easy way out and just file the opposing key and figure it will last until my time on Earth is up? I’d prefer to fix it properly though.

Dave

I’d just gas weld it to build it up and file the hole but I have that equipment .your over thinking it it’s just a fan. Tig welding produces a very hard weld