Thread: Replacing the stock generator with an alternator

is it a generator proper or an alternator?

I'm happy to see about coming up with one for a swap if yours is complete and workable.

It's a proper generator, long black thing looks like a kingswood starter motor lol. My old man thinks I'm nuts but I need more juice. I'll take some pics tonight but I don't want to fabricate anything I just want a nice bolt in job so I can't promise a swap at this stage plus I find it hard to let go ha ha.

pretty sure setting up an alternator to go onto a 2.25 isnt something thats going to cause me any heartache.

Here is a pic.

I have also heard that I might be able to get an auto electrician to fiddle with the regulator to extract more juice from the generator but I'm not sure really.

Kind of thinking about it atm and looking for more info.

from memory they are good for 20-25A

The problem with generators compared to alternators is that they need a lot higher engine rpm to produce their rated current, mainly because they need to have a larger pulley to prevent exceeding their safe rpm at high engine speeds. This means that they you will sometimes find the battery going flat if you do only night driving at low speeds even with the standard lights. Fiddling with the regulator to increase the current regulator setting will not help this problem at all. (The advantage of the generator is that it will start generating with a completely dead battery, allowing the vehicle to tow or roll start in this circumstance, where an alternator cannot start generating without a battery in reasonable condition - I have struck the situation where an engine can be crank started but the alternator will not charge because the exciting voltage is too low.)

The simplest way of fitting an alternator is to get the alternator and brackets from a Series 3 and fit that. Bolt on job and wiring has only trivial changes, even though the alternator is not perhaps the best you could get. Note however, if it is a pre-1967 2a with positive earth, the polarity must be changed to negative earth. Especially if fitting a larger alternator, on this pre-1967 setup the dash mounted ammeter means a long feed from the alternator to the battery and a voltage drop that will reduce the maximum charging current and may lead to overheating wiring. Plus the ammeter will be overscaling and may be damaged.

John

P.S. I'm inclined to agree with your old man - fit headlight relays before fitting higher wattage lights or extra lights - if you don't, you won't get a lot more light and will almost certainly damage the headlight switch. But the alternator will be a lot more reliable than the generator!

Thx heaps John. So now I am contemplating fitting relays to my high and low beam circuits because I did fit some narva 72040 h4 lights in place if my originals? Will this act in it's self stop the drain on my battery when I turn the headlights on because ATM when I turn my lights on at night the charge indicator reads 0 on the 55w low beam and when I turn on the 100w high beam and spot lights it goes into negative. Will the relays relieve the drain on the 55w at the least?

Hey guys I just want to send a big thank you to Jonh for solving my problem and saving me a lot of cash. I fitted relays to my high and low beams and there is relatively no draw what so ever on the amp meter and when I turn on my high beam (100w) and my 2 hella spotlights (100w) also, the amp meter actually shows the same amount of charge as when I'm doing daylight driving - no draw what so ever.

So basically I have no need to replace my generator but I have no seen a good reason to justify a whole new wiring loom eventually. Now it's only my indicator and stop lights that show a draw on the amp meter but as they are only on when I need them I can put that job off for a while.

Oh and sorry blacknight but I'll be keeping the old geny as there's life in it yet