9 replies to this topic

[blackbelt1990]

Right.... need a new alternator as my original is in several pieces!

Can anyone tell me what the rating of my standard alternator was? What can I upgrade it to? I'd prefer and alternator that covers 'just in case' rather than 'it'll do!'

Thanks! Ryan

[Jordie]

45 i think. But go for a 70 if you can find one.

[Dan]

A Tahiti would have had an A127, 55 amp I think but it may have been a 65, it's right around the change point. If you get a 75 then you should seriously think about upgrading the wiring from the alternator to the starter solenoid.

Incidentally, when you ask that type of question please put what car it is in the body of your post. We aren't psychic and not eveyone will think to look in the side bar or know what year a Tahiti is from. I'm not sure myself but I took a guess.

[AlexM]

If your using those spotlights get a 70.

Alternator.

[Big_Adam]

Got my 75 amp from a Nissan bluebird.

[blackbelt1990]

Ok, thanks. It's a 1994 Rover Mini Tahiti 1275cc

If I go for the 70, what wiring will I need to change. Is it a big job?

Ryan

[AlexM]

Shouldn't need to change wiring for the 70 really. I might need to get a new alternator and I have no plans to change any wiring if i do.....Maybe this is wrong of me.

Edited by summergnu, 11 February 2007 - 02:06 PM.

[Dan]

The main harness in these cars was originally designed for the 55 amp A 127 and wasn't changed when the 65 amp was added. I seem to remember that the main alternator hookup in this loom is a pair of 4.5mm cables which is fine for 55 amps or 60 amps but 70 is right at the limit of it. Add 10 years of corrosion (which increases resistance) in the wiring and it's not a good combination.

All you need to do is take another core of cable, something like 3 square mm cable (you can get brown auto cable at Halfords in fairly heavy gauge, 3mm would be marked as 27 amp at Halfords) to run from the alternator connector to the starter solenoid main terminal. Crimp an 8mm ring terminal onto the end for the solenoid, run it along and tape it to the existing loom to the alternator block. Open up the alternator block carefully, strip the end of the cable and run roughly half of it's cores (there are 44 in 3mm cable) to each of the two large terminals in the alternator block, soldering them firmly in place (I don't normally like solder in cars especially on the engine but in this case it's the easiest thing to do, you could get a new alternator block and double crimp the wires into the flag terminals if you wanted to do a more secure job). Make sure all the bare conductor is fully inside the block when the cover is reattached and make sure that none of the cores or solder have gone astray and shorted to the small terminal as this will mess up the function of the no-charge warning and make the battery die fairly fast when the car is left for any period.

That's it, it's only the charging circuit that needs improving as long as any accessories you have fitted (such as spotlamps) have been carefully installed.

[Elfie]

I rebushed mine today, I'm very proud of myself!!!

[icklemini]

to be honest, big alts are needed unless big current is being drawn (an work it out quite simply), they are often fitted to overcome a problem with poor connections in the wiring...

running a big alt puts increased load on the pully.. or more specifically the rubber that holds the pully together..

strip the end of the cable and run roughly half of it's cores (there are 44 in 3mm cable) to each of the two large terminals in the alternator block

easier to run a suplemental cable from the large threaded take off on the A127's (the larger of the threaded take off under the little black caps) - this is what i do.. saves messing with the plug and the original wiring...

TTFN,
Dave

Edited by icklemini, 11 February 2007 - 11:00 PM.