Defender Alternator Options

[Craig]

Hi

I have a 1994 300TDi Defender. The alternator is only putting out 12.5 volts and doesn’t seem to be giving the batteries a good charge.

I am looking into replacing the alternator and have had some different answers from various suppliers.

I have also been reading a few threads on this subject and have a few questions.

1: I am told that the 65 Amp (A127-65) is standard, and that if I fitted the 100 Amp (A127-100) from a Discovery it wouldn’t have any warranty by one supplier, only to have another supplier tell me that the 100 Amp is the standard.

2: I have read that there is a Bosch alternative but I can’t seem to find any information about it. Does anyone know the part number?

3: I have 2 AGM batteries which I am told can take a very high initial charge rate. Is it worth getting the higher amperage on?

4: Does anyone have any details/opinions regard going for the OEM or aftermarket.

Thanks in advance

Craig

[Reads90]

I have put a V8 3.9 disco one on a 300 Tdi in the past. They are a 100amp alternators. Will got straight in

[ladas]

As I understand it.

The 65 amp a127 is standard on the Defender TDi

The 100 amp a127i is standard on the Disco TDi

The reasoning for this, so I have been told, is because the Disco has more electronic/electical gadgets than the Defender.

Can't see how fitting a 100amp would interfer with warranty, especially as the parts catalogue list a 100 and a 120 amp as alternatives.

[Rosco]

I have put a V8 3.9 disco one on a 300 Tdi in the past. They are a 100amp alternators. Will got straight in


Don't the diesel alternators also have a vacuum pump on the back for the brakes??

[Reads90]

Don't the diesel alternators also have a vacuum pump on the back for the brakes??


No
Well not mine anyway.
1st did it with my 200 Tdi 90 challenge truck. Put a 3.9 V8 alternator on. But just changed the serpentine pulley for the old 200 Tdi v belt pulley. Easy job doen and then twice the power

[rangieman]

I have a 100 amp alt of a transit van on my defender if you want a part number let me know and ill post it:D

[BigJon]

Don't the diesel alternators also have a vacuum pump on the back for the brakes??

No, the vacuum pump on a Tdi is mounted to the drivers side of the engine and is driven off the camshaft.

The TD5 alternator has a vacuum pump on the back.

[justinc]

Confirming that the Disco 300Tdi alt will fit and is a 100 to 120 Amp unit. It is also of better quality and is rebuildable properly, as the A127 65 amp defender one is a throw away when the rear bearing fails.

JC

[Blknight.aus]

12.5v is too low unless your trying to draw say 110-115% of rated amps...

might be an easy fix with a dodgy internal regulator...

the the v8 3.9l atlernator bolts onto a tdi20o IVe done that once but thats as far as I go..

[camel_landy]

The 100Amp unit is an optional fit for the 300TDi Defender, no modifications needed. My truck has the 100Amp unit.

As for charge... The alternator should be putting out approx 13.8v IIRC.

M

[Reads90]

The 100Amp unit is an optional fit for the 300TDi Defender, no modifications needed. My truck has the 100Amp unit.

As for charge... The alternator should be putting out approx 13.8v IIRC.

M

Hi Mark
I knew you be on here with all the details:) :)

BTW how was Gaydon:)
Did you see jules in his RR LSE

[Outlaw]

post away rangieman

[rangieman]

post away rangieman

Ok its a magneti marelli # MXA828
A12IR -100A-14V
AND A 3 YEAR WARRANTY:D
hope this helps guys

[rick130]

go here http://www.baxters.com.au/index.php?page=results for (http://www.baxters.com.au/index.php?page=results)
for a comparison of the different Magneti Marelli alternators.
Click on each one to give you a full description/specification (except rangieman's Transit one at the bottom of the page )

[camel_landy]

Hi Mark
I knew you be on here with all the details:) :)

BTW how was Gaydon:)
Did you see jules in his RR LSE

:)

Nope, didn't make Gaydon... Weather was 'changeable' and as the museum was closed I couldn't be bothered. I went out off-roading with Jnr instead... (Bent the bull-bar & both rear qtrs. :D )

Mind you, I've seen the LSE already... :cool:

M

[rangieman]

go here http://www.baxters.com.au/index.php?page=results for (http://www.baxters.com.au/index.php?page=results)
for a comparison of the different Magneti Marelli alternators.
Click on each one to give you a full description/specification (except rangieman's Transit one at the bottom of the page )

Well thats the one i have on my 300 Tdi defender the only mod i did was change the pulley:D

[rick130]

Well thats the one i have on my 300 Tdi defender the only mod i did was change the pulley:D

and you haven't mentioned the all important $$ yet ;)

[Reads90]

and you haven't mentioned the all important $$ yet ;)


Yeah come on spill the beans :)

[rangieman]

and you haven't mentioned the all important $$ yet ;)
$450.00
I needed it in a hurry so im sure the price could come down , i got it from a local auto elec he was very helpfull he just cross referenced it and came up with the ford transit 100 amp alt:D

[sclarke]

Damn i want a bigger one for like $100

Ahhh off to the wreckers

[Craig]

Thanks for all the replies guys,

Well its a few months later and I have my new 100 amp model from the Disc and ready to fit it to the Defender
However… the old one has two connections (B+ and D+) and the new one has three connections (B+, D+ and W).

Does anyone know if there is any special way to wire this up?

Thanks


Craig

[MacMan]

I've done it on my home jigged Bosch alternator out of a Magna Verada but I dunno about the Marelli one. Bloody stupid complicated italian rubbish! Splitting those required unsoldering of all the coils if they are anything like the original I had.

http://members.optusnet.com.au/mac.man/alternator_swap/

This shows how I did the W wire. It's a simple AC pickup from ONE of the field coils.

[MacMan]

BTW - the W terminal is the source for you're tacho. The others are the main output and the battery sense terminals.

[incisor]

Thanks for all the replies guys,

Well its a few months later and I have my new 100 amp model from the Disc and ready to fit it to the Defender
However… the old one has two connections (B+ and D+) and the new one has three connections (B+, D+ and W).

Does anyone know if there is any special way to wire this up?

Thanks


Craig
the extra one is for the tacho

on the old defender one it has a rubber cover over the unused tacho fitting point which is a screw on fitting not a blade (or mine did)

[rick130]

the OEX number for the Disco Tdi 100 amp MM alternator is

MXA 831

hole diam 8.2mm
adj hole to pivot 148mm
foot to foot 80mm
pulley diam 53mm, 7 PV groove.

[jik22]

I have a 100 amp alt of a transit van on my defender if you want a part number let me know and ill post it:D

That would be useful. Did yours have the extra terminal for the tacho feed?

[rangieman]

That would be useful. Did yours have the extra terminal for the tacho feed?
Yes it does its the same alt that suits a ford transit van:D

[RhinoH]

Sorry for the thread dig, but can someone tell me the part number of a 100 amp alternator that will fit in a 300TDI Defender?

[weeds]

Sorry for the thread dig, but can someone tell me the part number of a 100 amp alternator that will fit in a 300TDI Defender?

I ordered locally and ask for a 300tdi disco alternator.

[Reads90]

I ordered locally and ask for a 300tdi disco alternator.

That is what I have always done too

[mrb505]

Still have the box with the old one in it140009

[Don 130]

And here's a link (https://www.ebay.com.au/itm/LAND-ROVER-ALTERNATOR-300TDI-120-AMP-12V-YLE10113-MARELLI-TYPE-BRAND-NEW-/362167192425) to the 120 amp version.
Don.