The Triumph Dolomite Club - Discussion Forum

Is there a difference between alternators for cars from 76 on and before?

Graham

It's too dark to see at the mo, but from memory, the 73 sprint wants the one described in the attached picture as right hang. Is that right?

Only, accu-spark have the right hang one as right for all the other Dolomites, and the left hang one for the Sprints. Where I think that left hang one fits the TR7 and so is the opposite one to that for the Sprint.

I just saw the voltage meter was off scale, so I checked with a DVM across the battery and that said 16v. I put the lights on, and it went back down to a bit over 13v on the meter, but I think the car's staying off till I get a replacement alternator - I've never liked the one that's on, it makes random noises.

Graham

Correct, the Sprint uses the one on the left

There is a common misconception here. Yes the Sprint and the 1850 use the "right hang" design of alternator, but the OHV cars use the SAME "right hang" design mounted upside down, as it were, on the other side of the engine.
So they are basically the same throughout the range and, in the early years were all probably the same 35amp 17ACR type. I believe the Toledo and 1500FWD of 1970, the first of the Dolomite nosed family, were the first Triumphs to be all equipped with alternators as standard.

The tech was that new then and since a 35 amp alternator was such a huge improvement over a dynamo that could seldom produce more than 22 amps, no-one thought it would be needful to be putting bigger ones on. History has sure proved THAT one wrong, the alternator on the Dolomega, pulled from the donor Omega, is 120 amps output and it isn't the biggest one available for that engine! Handy when adding gadgets though!

There is a difference in the alternator MOUNTING between early Sprints and later ones, but its actually in the water pump housing! Series 1 cars (up to VA 15000) you can only remove the long alternator pivot bolt from the front, which means removing the radiator for clearance if you need to change the alternator. A redesign of the water pump cover, to stop it getting in the way, meant the bolt COULD be inserted from the rear and the alternator changed without pulling the rad (though the FACTORY still put the bolt in from the front, masterpiece!)

Steve

Thanks Steve, I already knew the 1300 and 1500 engines take the same mounting alternator as the Sprint, as I replaced the dynamo on the Herald with one, and rebuilt the regulator as a fuse box. But the Herald is away (still) being fixed, so I couldn't look at that either. I wasn't sure if the 1850 was like the TR7 or like the Sprint. It made sense it would be like the Sprint. But then it makes less sense that the TR7 (and TR7 Sprint) is the other hang - there's more access there in the 7 than the doli, not less.

I'm assuming that 16v on the battery can only be from an alternator fault.

I've never looked at overhauling an alternator myself, e.g. replace the regulator/rectifier. And this one makes random knocking noises when running - though until now has been working fine. So I'm not sure I want to do aught with it. But I do have the last one that went - it must be somewhere in the shed.

But I do want a slightly bigger one than standard, as I've a 120 Watt electric fan fitted. Another 10 Amps should more than cover that, though. The stereo is not that big it needs special consideration.

Graham

You can change a right hang alternator to a left hang, at least on Lucas ACR types, simply by removing the 3 through bolts and turning the front end plate through 120 degrees and refitting the screws. Though I only do this in cases of severe need!

If it's chucking out 16v then the regulator is fubared, no question. My old GT6 did this on a run down to London and MELTED the battery! It's not that hard to put a kit in an ACR alternator, rectifier, regulator and brushes, but if it's knocking and grumbling I wouldn't bother, i've not had much luck changing bearings, the cases are too delicate for my hamfisted methods.

Steve

GrahamFountain wrote: ↑Tue Jul 25, 2023 11:41 am
But I do want a slightly bigger one than standard, as I've a 120 Watt electric fan fitted. Another 10 Amps should more than cover that, though.

Worth checking the real current draw of the fan. The 3 or 4 I have checked have drawn the rated current ONLY at startup, and immediately drop to half. However, I have not checked my Spal.

I gave up on the Lucas ACRs a few years ago. And wouldn't touch a modern version with a long bargepole. I have been using genuine Denso 40A alternators, but equally any genuine Bosch, delco etc would be a good shout. My 40A Denso happilly ran my Toledo with heater running, spotlights and stereo (which is diddly squat) for the entire RBRR. Twice. That car had an electric fan, but I doubt that cut in at all. Even if it did, it should only run for a few minutes.

I had a search around in here and found a recommendation for a later Lucas A127, 70 Amp one, which seems a cost-effective solution. So I've ordered one of those. It's probably OTT in output current, if it's correct, but I can't see any obviously significant downside to that.

Graham

The A127 (as fitted to the Montego, Maestro etc) is a direct replacement requiring no modifications; even the multi plug fits straight into the back of it.

Sprint (and some late 1850) was fitted with 17 ACR, smaller engined cars had the 15 ACR identifiable by the lesser number of bands creating a slightly shorter unit

The problem will come that I have to fit this right-hand alternator mostly left handedly, as my right is still wrong.

But I'm certain the long bolt is in from the back - the engine is a later replacement, and I did this job about 3 years ago. So I'm not going to have to pull the rad.

Hopefully this new alternator will last a bit longer than the one that's in.

Graham

There aren't many accesories that, in themselves, constitute a large battery drain and hence need more alternator power to cope. The only one I can think of that singularily demands a ton of alternator power and battery capacity is the electro/hydraulic PAS pump on Vauxhalls, even a Astra so fitted has a 180A alternator and it NEEDS every one of them! Whether the pure electric PAS fitted by the likes of Easysteer and used on Dolomite PAS conversions demand similar extravagant power I don't know, but I assume not so bad, as no-one who has converted has mentioned it.

But if you consider climbing a mountain on the RBRR at night, it's cold and raining and EVERYTHING is on, 280watts of Halogen main beam and 150 of spotlights, HRW, wipers, heater fan, maybe rad fan too and a dozen other minor lights and gadgets, the demand adds up fast!

I never count stereos as the draw they demand is usually negligible UNLESS you have a massive power amplifier, a very specialized bit of kit not normally associated with classic car owners.

Maybe i'm a bit paranoid, I come from the generation of dynamos and giant lead/acid batteries that take a long time to die. I still run on sidelights under streetlights to save power and don't switch the wipers on till visibilty drops to zero and then only 1 or 2 wipes.

Steve

I have the old one out with no real problems. However, the bolt holding the alternator mount adjusting strap on to the front of the engine was loose. Not at the point of falling out, as such, but not tight neither.

Is there a solution for holding that bolt, while allowing the support arm to move a bit? Or is it reaching round the back of the alternator to slack-off and re-tighten at each adjustment?

Graham

Carledo wrote: ↑Wed Jul 26, 2023 3:24 pm There aren't many accesories that, in themselves, constitute a large battery drain and hence need more alternator power to cope.

Steve

I'm only counting the fan, and then with appreciation of cliftyhanger's point that 9 to 10 Amps will be peak. I've also got an electric fan heater for the back window, but it's not that big an issue.

I don't think I've a problem with the stereo in the Doli that needs more power from the alternator. But I've got both supplies to it from the battery as thick and direct as possible - the switched one is through a relay rather than through the ignition switch. That's because there was some distortion on big bass excursions on the standard wiring - there don't seem to be a consensus on which needs a high capacity feed from the battery, so I did it to both (and the earth of course) while I was at it. But they're only 8" woofers in the back shelf, so it's not that OTT. I'd quote the wattage of the amp, but I don't even believe those from Pioneer.

Graham

I had a noisy bearing under load on my old “std” sprint alternator.

Put an a127 70A one on as recommended by the guys on here as a replacement. Seems to work fine.
(A right hang one)
Voltage and on the volt meter never drops below 13 even with fan, lights and the ICE on.