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TR4/4A Recommendation on alternator upgrade for TR4A

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Hi everyone - the TR4A needs a new alternator and I was wondering what you all would recommend. I do not have plans to run lots of electrical equipment, but would like to switch over to a more modern alternator.

The car has a stock alternator installed currently.

Thanks in advance for the ideas!
 
Hi,

There has been a ton of discussions here on BCF about using the Delco 7127-3. With some minor modifcations and tweaking, that will work in your car and is very widely available and cheap (usually $45-$60 rebuilt). Just search the BCF archives. This alternator will put out around 60-65 amps, compared to the 22 amps your TR's generator will produce at best.

The only downside of the 6127-3 is that it's not any lighter or smaller than the original Lucas generator. (I'd love to find a smaller/lighter alternator that produces 45 to 60 amps, if anyone has a suggestion.)

There are also several very detailed discussions on the web regarding how to install it: try VTR.org's maintenance section for one. Google for others. ISTR most recently Tinster put one in his TR and posted some photos about it. He did disassemble the alternator in order to paint it, which would only be for personal preferences. (I'd suggest not disassembling it, probably voids any warranty.) Another tip, there will need to be some grinding done on the alternator case to make it fit (see the various articles, you'll see why) and care needs to be taken to not get any of the grinding grit into the alternator, so tape it up to keep any waiyward dust out of the armature and bearings.

Also, you'll need to decide if you want to convert to a thin belt or keep the wide original. If wide, you'll need a special pulley for the alternator (most come with a thin belt pulley). If changing to a thin belt, you'll need compatible pulleys at the crank and at the water pump.

Thin belt conversions can be purchased as a kit.

This change is often done when converting to an electric fan (which ideally needs the extra output of an alternator) and removing the 4-blade fan and it's hub/extension from the TR engine. If this is done, a harmonic balancer/pulley is needed at the crankshaft. (Some just run without the fan extension or balancer, but that's not recommended for the engine/gearbox, long term.)

There are a few photos of the 7127-3, thin belt conversion, harmonic balancer and electric fan installation on my TR4 (identical with respect to these parts on your car), at the link below in my signature.

/ubbthreads/images/graemlins/cheers.gif
 
P.S. Keep your old Lucas generator in case you ever sell the car. A buyer might be concerned about originality. Also, that old generator is easily rebuildable, probably locally.

And, I forgot to mention another option... Somewhere on the web or in one of the discussion groups I saw something about sending off the old Lucas generator to have it internally converted to a higher output alternator. I think it was someplace in England doing it, but can't be sure about this. Probably pretty expensive, plus shipping to and from. But, might be a way to maintain originality and still get higher electrical output, all with minimal fuss. Downside might be if the converted Lucas is difficult to get serviced or rebuilt again in the future... I don't know about that.
 
I am scratching my head wondering what a "stock "alternator on a tr4a looks like.?????
You might want to see the set-up Prather Racing uses on its vintage preped cars.50amp single wire the size of a nice apple.Japan makes good electrics and this is a Kioto(if I recall).
MD(mad dog)
 
[ QUOTE ]
I am scratching my head wondering what a "stock "alternator on a tr4a looks like.?????

[/ QUOTE ]Well...according to the Triumph TR6 - TR5 - TR250 Repair Operations Manual, it would look like any other Lucas 11AC (with a separate regulator like that of the TR250, which used the Lucas 15AC alternator). According to this book and other references I've seen, these alternators were acutally available in both negative and POSITIVE ground versions. /ubbthreads/images/graemlins/smile.gif
 
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