Original ammeter

[xb-60]

I need some ammeter information.
Is this ammeter....



....a Smiths or a Lucas unit?
Would it have an identifying number?
Was this particular style used for all of the Cobras up to CSX2200?

Cheers,
Glen

[1985 CCX]

Looks correct for Smith's "Equipped" cars. Based on picture attached...
Joseph Lucas MFG

[CompClassics]

Smiths as Jeff said.

[xb-60]

So it would have a number (like AM 2300/01 for example....but not that one)
Any spring to mind?

Cheers
Glen

[rsk289]

Sorry Glen, your photo won't appear (blue box with question mark), but I can tell you that the correct ammeter for a leafspring car is a Lucas BM4. It doesn't match the other Smiths instruments, and is a 30-0-30 instrument with a pendulum needle shaped like an arrow. It has a full printed scale but no part number visible on the face.
'BM' stands for 'Bakelite Moulded', or maybe 'Base (or Back) Moulded', borne out by the screw terminals on the back being set in the moulded bakelite casing. There is no screw post for a clamp as the ammeter is a push fit in the dash, with small tangs on the chrome bezel to help retain it. It relies on illumination coming from the external bulb on the fuel gauge and has no bulb of its own.

Roger

[blue sky]

Glen,
Roger is correct. It is a Lucas BM4 model. Part number for that particular unit is 36200B. For the BM4 ammeters, the part number was stamped on the side of the chrome plated brass bezel. The tabs on the bezels had a tendency to break off when the instrument was worked on, so sometimes they were replaced with one with another part number. These bezels are also being reproduced in the UK.
AJ

[xb-60]

Thanks for the replies. Yes I originally thought it was a Smiths too, and obviously it was fitted to to the original 260/289 Smiths-instumented cars.
I found the Lucas parts listings with the model interpretations. Roger, it's definitely a BM4 that I'm after (and yep, BM means base moulded, and "4" means it has a damped movement).
AJ, I now have a list of eleven Lucas 'BM4-family' ammeter model numbers that are correct or could easily be modified to be correct.
They do appear to be rare though, but where's the fun if there's no chase?

Cheers,
Glen

[rsk289]

Are you sure that the '4' refers to 'damped'? I've had several of these over the years on various cars, and just like the one currently on my Cobra, the needles have never appeared to be damped. It usually oscillates so quickly it's quite hard to see, and there's no damping mechanism visible inside.

I didn't bother too much about the actual part number as it's not visible when the instrument is installed. They do come up on ebay UK now and then, but you have to plough through a lot of motorcycle versions to find them. Nothing showing at the moment, though - I'd search 'Lucas ammeter' or 'Lucas amp' on the UK site. 'Lucas amp' throws up this, which is only a 20-0-20 but could easily be refaced:

VINTAGE JOSEPH LUCAS BM4 20 AMP AMMETER GAUGE FITS AUSTIN MORRIS RILEY MG | eBay

Roger

[blue sky]

Roger, I may be wrong, but I don't think you can run a generator with a higher amperage through an ammeter of lessor capacity (the C40 generator puts out 30 amps). I was told by a service that the internal coil of the amp can't handle it. The 30 amp BM4 come up for auction on the UK Ebay. I have gotten a number of them there.

[CompClassics]

Sorry I had a brain fart, the gauge is actually a Lucas unit (brought to my attention by Dan C), I have sitting here at the shop on an early Cobra I am restoring...

[xb-60]

Hey, we all get brain farts (don't we?).
I did see the similar 20 amp gauge on EBay yesterday. I also saw a 30 amp gauge for GBP 429
It's like most rare things we chase for our cars, they will eventually come up within range of our acceptable price.

Cheers,
Glen

[rsk289]

Well, if there are no components drawing more than 30A, it doesn't have to be able to handle anything over 30A. Unless there is a huge stereo system, extra lights everywhere etc. the only thing that might draw high current is the cooling fan. A generator/alternator won't produce 30A unless a component is asking for it.
Having said that, I had my 30A BM4 ammeter upgraded by Speedycables internally to handle 50A just in case, as I have a pretty big aftermarket electric fan to try to keep the thing cool in traffic. There's no way of knowing visually that the ammeter has been uprated - it just doesn't deflect quite as far as it used to. Frankly I think they're only useful for showing charge/discharge.

[xb-60]

Roger, my ideal plan (haha) would see the fitment of a Lucas generator, so not thinking of big current draw. I have a big lump of cast iron (a very early Mustang gennie bracket) stowed somewhere in my garage. A lot of other things need to slot in place first though....and I'm getting off-topic a little.....

Cheers,
Glen

[rsk289]

I think the Lucas generator used a fabricated steel bracket, which Gerry at Hawk Cars is now remanufacturing.
I have a couple of Sunbeam Tiger 260/289 generator brackets, which are the big heavy cast iron variety - but these were for the Autolite generator, which I also have one of if anyone's interested.
My 289 has a Lucas generator (Dynator) with the fabricated steel brackets and a tacho drive off the rear.

[Dan Case]

Originally Posted by rsk289

I think the Lucas generator used a fabricated steel bracket,

More specifically, CSX2xxx Cobras fitted with any of the versions of 260 c.i.d. engines received Lucas® tachometer drive generators with large diameter cast aluminum sheave and fan combinations mounted on fabricated steel mounting brackets. (These comments don’t cover COB or COX prefix chassis.)

During December 1962, see Bob Mannel’s book, Ford started production of the High Performance 289 engine. Initial production must have been real slow because I have seen very few parts dated in that time frame. At the introduction of the HP289 engine Ford generators and Ford mounting and adjustment parts replaced what AC Cars had been supplying as far as CSX20xx cars were concerned when engine supplies met up with chassis in need of engines. HP289 engine production got faster circa February 1963 and relatively large numbers of HP289 specific pieces dated March 1963 are circulating.

One cannot rely on chassis numbers alone because chassis were not finished in order. The type or vintage of engine a chassis received depended on what was available at the time somebody got to the point of installing an engine.

Summary Of CSX2xxx Street Cars With British Electrical Systems :
Early cars with XHP-260, HP260, or Fairlane 260 2-V (CSX2006) engines: Expect Lucas tachometer drive generator, large cast aluminum sheave/fan, and fabricated steel generator mounting system supplied by AC cars.

CSX20xx through CSX2200 except CSX2126: Expect some version of Ford Fairlane HP289 (Ford made several design level changes of parts or whole assemblies more than once per model year.) engine with Ford charging system components; HP289 generator assembly with large diameter sheave (not the high performance FE engine style sheave), Ford cast steel mounting bracket, and Ford wrought steel adjustment arm.

[rsk289]

Dan, as far as I can tell from my access to COB/COX cars, they continued with the Lucas generator and fabricated bracket, at least up to around December '64.

Roger

[xb-60]

Again this forum shows its worth. Thankyou.

Cheers,
Glen

[CompClassics]

Here is what the early Lucas cast pulley looks like...

rsk289,
Are you sure about 1965, maybe 1964?

[rsk289]

Sorry, yes, my typo - December 1964.

[Dan Case]

Originally Posted by rsk289

Dan, as far as I can tell from my access to COB/COX cars, they continued with the Lucas generator and fabricated bracket, at least up to around September '65.

Roger

For clarity, CSX20xx production cars fitted with XHP-260, HP260, or in case a 260 2V engine used the Lucas® tachometer drive generator and gear reducer, AC Cars fabricated mounting and adjusting hardware, and large AC Cars racing cast aluminum sheave and fan part. When HP289 engines were introduced the engine installations included the corresponding Ford Fairlane with HP289 pieces. So far based on old pictures and or cars little changed since the 1960s that includes most cars that SAI did engine swaps on to remove some 260 or another and install a HP289.