Thread: what alternator /

IMHO the easiest is a Bosch 85 amp from a Magna TE?ie the one around 1990. They cost about $200 or so new.
The brackets are in a similar position but you have to do a number of mods.
1 make up an extender for the adjuster, about 3 inches long.

2 if you want to use the normal belt, grind a notch in the mounting bracket about 1/2 inch deep to allow the alternator to swing in far enough.

3 Some of the alternators have multi rib pulleys so you have to find the smallest V pulley available, then muck round with it to align the pulley with the PS pulley. The Lucas pulley is juuust too big and is a sloppy fit, but remember the tacho depends on a pulley the same size as the Lucas to be accurate. AFAIK, none are available for Bosch as small . Mine is 67mm vs 63mm AFAIR.

4 You have to organise a field wire for the tacho. I bought mine from an auto electrician who wired it for $40.

5 If you are a purist like me drill out the holes in the mounting bracket to suit the larger holes in the alternator and use bigger bolts. I used the smaller holes for several years but found the alternator was slightly "jacking" to a slight angle vs the belt.

6 The alternators have an injector plug on top for the exciter so you have to wire the small wire for the light into it.

7 The Bosch is a battery sensed alternator so you have to run a wire directly to the battery from the injector plug.

8 You should reroute the wires from the distributor to the coil well away from the alternator as there is a known problem that Bosch cause a lot of "hash" that can cause the ignition to malfunction.

It sounds a lot but it is all pretty simple. The Boschs are reliable as far as bearings etc but the regulators are a bit sus. Mine died in Kakadu but the bottom line is the parts are easy to get. I was able to drive to Darwin on my other alternator and buy one ( Sorry Mate no Magna , but what about a Commodore? Yep Exactly the same ) at Repco for $52.

The Mechanic at Jabiru had 6 alternators but no regulators! but it would have only been a couple of days wait for one, vs who knows how long to fix a Lucas.
Regards Philip A

thanks for the help , will do

hi philip a your post was really interesting i have always had bosch alternators and i am interested to know what you mean by they create "hash" if you could please explain this concept further thanks in advance

I did similar to Philip but I used the Bosch from the v8 falcon ( I think au but may have been ba).

It cost $180 and only needed a spacer installed to fit. I had the auto elec put the pulley from old alternator on it.

hi philip a your post was really interesting i have always had bosch alternators and i am interested to know what you mean by they create "hash" if you could please explain this concept further thanks in advance 23rd February 2009 08:31 AM

There is a well known problem with RRC V8s with Bosch alternators that the engine starts to miss at 2.5K to 3K revs, and it is worse under high electrical load such as lights/aircon on.

The fix as told to me by Graeme Cooper many years ago is to move the wires to the coil from the dizzy away from the alternator, or to shield and earth at both ends.
Nobody knows exactly why they do it but the theory is the alternators are not shielded well enough and induce RF or stray AC into the coil signal.
Regards Philip A

Thanks thats really interesting and its great to learn something new, i think i will be moddifying my wiring (yet again). How do you earth both ends ?