Aussie members: Swap to a Falcon/Bosch alternator?

ewokracing

ewokracing

Active Member
Hello

was chatting to one of the guys at work that's into triumphs and the same sort of bikes as me and I said something about the Rover not charging. He asked if it had a lucas (which it does) alternator or a bosch. He suggested that there may be a direct replacement Bosch unit from one of the E or X series falcons - anyone off here done the same swap?

Also, what's the amp rating on the p6b alternator? I think I saw 70 somewhere, just that I know the early ford stuff is around 55/50 and I don't want to go backwards!

Cheers
 
Hello Geoff,

The Lucas 18ACR alternator which is what is fitted to your Rover and mine has a 45 Amp maximum output at 6000rpm. For all of the ancillaries fitted, it is sufficient. Where more modern alternators have the advantage is that they deliver more current at lower engine revs, so as an example at idle while in traffic with the headlights on, flasher going etc when the 18ACR will deliver a shortfall and the ammeter shows a discharge, the modern issue will cover the current drawn and the ammeter will sit on zero as it usually does when in a state of equilibrium.

The beauty of the 18ACR is that they are easy to work on, parts such as regulator and brushes, rectifier pack, bearings and slip ring are all readily available from suppliers in the U.K, and you can do the overhaul yourself. If your ignition light comes on and stays on then the problem is either worn brushes or the regulator has failed. If the light comes on at idle and then fades as engine revs increase, then one or more diodes within the bridge have failed. The slip ring should see more than 200,000 miles (320,000km) without too much of a problem.

I have never heard of alternators off Falcons being a suitable replacement.

Ron.
 
I don't know about replacing the whole unit but I certainly need to find a replacement cover for the spinning blade bit, I've almost taken my hand off about 3 times coming too close to the exposed spinning bit on mine as its cover is missing!!

Surely out of the factory there would be a plastic shield or something that's missing from mine?
 
SydneyRoverP6B said:
Hello Geoff,

The Lucas 18ACR alternator which is what is fitted to your Rover and mine has a 45 Amp maximum output at 6000rpm. Ron.
Click to expand...

:LOL: That is sort of like British or American horsepower, only in someones wet dream :roll: Unreal ratings pervade the motor industry, personally I would look for a Jap self contained unit if you want real amps at realistic RPM. Could you imagine your P6B at 6000 RPM???? in any driving style?? I would suggest that the real rating would be closer to 20 Amps max at normal road speed RPM and only if the Brushes and slip rings were in top order, whereas your nice reliable Jap unit will give you accurate face plate rated currents and many of these alternators are rated at 90 to 120 Amp to deal with the more modern power requirements of current cars.

Graeme
 
ghce wrote,...
That is sort of like British or American horsepower, only in someones wet dream Unreal ratings pervade the motor industry, personally I would look for a Jap self contained unit if you want real amps at realistic RPM. Could you imagine your P6B at 6000 RPM????
Click to expand...

Hello Graeme,

That is alternator rpm, not engine rpm.

Ron.
 
:oops: true lol. I have always liked the ACR alternators for thee inbuilt regulator and relative reliability and they do work well with traditonial flooded lead acid batteries but the low speed of the altetrnator at idle has always annoyed me, the factory really should have fitted a smaller pulley, I am quite sure the average motorist would rarely overspeed it in the V8.

Graeme
 
ghce said:
whereas your nice reliable Jap unit will give you accurate face plate rated currents and many of these alternators are rated at 90 to 120 Amp to deal with the more modern power requirements of current cars.

Graeme
Click to expand...

But don't Jap units have a disadvantage in that they're really difficult/cumbersome/expensive to overhaul? Granted they might be gazillion times more reliable than Lucas units and hardly ever need to be overhauled until a great amount of mileage/km's.
 
I guess that depends on your location, here in NZ where Jap cars predominate it is probably cheaper than a european equivilent, though still not cheap mainly because NZ has become a high cost economy due to wage expectation and silly goverment tax handouts to every one resulting in artificial non reality in pricing........bring back slave labour I say!

Graeme
 
darth sidious said:
But don't Jap units have a disadvantage in that they're really difficult/cumbersome/expensive to overhaul? Granted they might be gazillion times more reliable than Lucas units and hardly ever need to be overhauled until a great amount of mileage/km's.
Click to expand...

no, Japanese ones ie mitsubishi, units are usually very easy to disasemble or test etc.

I can only think of a few tricky ones (I can't remember the make or cars they come off) but you need to drill a small hole in the back of them to push a nail or a pin through to get the rear bearing out.

I will do some measuring at my friend's house this arvo - possibly if my face doesn't melt off in the heat.
 
I used a Bosch alternator (125 Amp) on my 4.6 engine. No issues with fitment, although you obviously have to be slightly creative in sorting out the connections from the loom to the alternator.

That said, I don't see any particular reason to change make when the Lucas one is so easy and cheap to repair. If you have already proved that you need more output perhaps, but I think you are a long way from that point.

Chris
 
ewokracing said:
darth sidious said:
But don't Jap units have a disadvantage in that they're really difficult/cumbersome/expensive to overhaul? Granted they might be gazillion times more reliable than Lucas units and hardly ever need to be overhauled until a great amount of mileage/km's.
Click to expand...

no, Japanese ones ie mitsubishi, units are usually very easy to disasemble or test etc.

I can only think of a few tricky ones (I can't remember the make or cars they come off) but you need to drill a small hole in the back of them to push a nail or a pin through to get the rear bearing out.
Click to expand...

I stand corrected then. :D
 
So a bit over 5 years later, I finally got around to test fitting a Bosch alternator. Yeah I'm a bit slow...

The reason for this is that 1) I don't think the Lucas one is efficient and 2) I want to be able to add in a few electrical 'toys' down the track and I think the Lucas one would struggle to charge the battery with headlights, heater, wipers and the radio etc

So here's where I am at:

Mine's a very late Series II car, so I have the three plug connector on the back of my Lucas alternator along with a single wire with a spade connector.

Three wires on the plug connector are:

- Brown with a white stripe x 2 - from the wiring schematic these are for the Ammeter and Ammeter shunt. (What's the shunt do?)
- Brown with a black stripe x 1 - from the wiring schematic this is for the Warning Light on the dashboard (more about this below)

The single spade connector wire is Brown and connects to the battery.


On the Bosch alternator I have got, I have a B+ connector, a D+ connector and D- and + markings.
From what I've read, B+ connects to the battery
D+ connects to the warning light

D- and + are not used.


Questions:
Do I connect the Brown/white wires to the B+ connector on the alternator along with the Brown wire?
I'm guessing that the Brown/black wire connects to D+ so that the warning light will work?
Why are the Brown/white wires a heavy gauge of wire along with the Brown/black wire (the ones on the one plug that goes to the back of the alternator), while the Brown wire which runs to the battery is relatively thin? Surely this should be a heavy gauge wire too?
Finally, what wattage is the warning light bulb? I've read that it must be 2 watts at least etc.

Pictures to follow....
 
The two wires with big spade connectors both do the same thing, from memory they both take the same silly route to the back of the Ammeter via the shunt. the shunt is a resistor across the back of the Ammeter which carries most of the current the two are in parralell so full current doesn't need to go through the ammeter. It is also used as a bus bar to connect other wires in. the wires themsleves go from alternator to the firewall then across to the other side of the dash and back again to the Ammeter. So if you short it out you melt the whole harness...also the 18ACR alternator really requires a shunt with higher resistance if you want the Ammeter to move at all.
 
The Lucas alternator on the later P6's is a battery sensed one . The brown thin wire carry's virtually no current, it is to pick up the battery voltage without any voltage drop associated with wires carrying a heavy current with umpteen terminals as well. Keeps the battery topped up better. Later Lucas versions went to machine sensed, ie uses voltage sensing at the alternator end not the battery .
 
So some people have said to bypass the ammeter completely, or to have it converted to a volt meter (but obviously keep the ammeter face to look factory.

Can I leave the two ammeter wires unplugged, then run a wire from the back of the Bosch alternator to the battery? I'm thinking this is probably the easiest solution!
 
So I ended up having a chat with some very bright electrical guys from the Uni I used to work with over a pint and problem sorted.

Can either run brown/white wires to charging point from alternator, no problem. Ammeter will work. Just need to be careful that the alternator doesn't put out over 60amp because thats all the gauge shows. However, given that I've read about ammeter equipped cars going up in flames, I was told to bypass altogether and just run a new wire to the starter.

So today a friend and I ran a new heavy 50amp rated wire from the B+ terminal on the battery to the point on the starter solenoid where the heavy gauge wire comes from the body.

Turn key, 14.05 volts output from the alternator, 13.9 with the high beam outer lights on (no idea but inner high beam lights have stopped working).

Warning light also connected, just made up a small jumper cable from loom to rear of alternator. The whole shebang is in bright read wiring, so it's not pretty looking but it works. The warning light stayed off the whole drive home tonight, whereas it used to flicker whenever I came to a stop.


Next up will be to upgrade and fix the headlights. I also need to perfect the alternator adjuster bracket as it is at the end of it's extension, so as the new belt stretches, the alternator output will drop, but I can't adjust it further. (or switch to a smaller belt).
 
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