Best of Both Worlds

[chadler]

I've just completed the install of a complete 300tdi wiring harness to the 200tdi. This was the change point that land rover went from individual bullet connectors to colour coded multiplugs, and makes the dash and instrumentation wiring neater and more reliable as individual plugs won't pop off and leave you wondering what they mate with. I'll put together a tech post with pictures when the final connections are done, as it's worth putting my aquired knowledge back into the forum in case anyone else ever comes to do this.

One question though at this stage; My 200tdi Alternator (A127-45) had 3 connections going to it, 2 large brown wires with black tracers which go from the main positive stud on the starter to 2 of the 3 pins on a multiplug that connects to the back of the alternator, the third connection is a thin brown and yellow that goes to the battery warning light in the dash. The 300 loom, has one fat brown and the thin yellow, these have ring terminals rather than multiplug connections at the alternator end. Do 300 tdi (65 amp) alts have post and ring connections on as standard? In which case i might as well fit a 300 alt and get the 20 amp increase in output, keeping the wiring standard. Or, if i were to adapt the new 300 wiring set up to use the 200 alt by putting the multiplug on, do i run a third brown wire from the third pin back to the starter positive post?

[Kim Horsevad]

I've just completed the install of a complete 300tdi wiring harness to the 200tdi. This was the change point that land rover went from individual bullet connectors to colour coded multiplugs, and makes the dash and instrumentation wiring neater and more reliable as individual plugs won't pop off and leave you wondering what they mate with. I'll put together a tech post with pictures when the final connections are done, as it's worth putting my aquired knowledge back into the forum in case anyone else ever comes to do this.

One question though at this stage; My 200tdi Alternator (A127-45) had 3 connections going to it, 2 large brown wires with black tracers which go from the main positive stud on the starter to 2 of the 3 pins on a multiplug that connects to the back of the alternator, the third connection is a thin brown and yellow that goes to the battery warning light in the dash. The 300 loom, has one fat brown and the thin yellow, these have ring terminals rather than multiplug connections at the alternator end. Do 300 tdi (65 amp) alts have post and ring connections on as standard? In which case i might as well fit a 300 alt and get the 20 amp increase in output, keeping the wiring standard. Or, if i were to adapt the new 300 wiring set up to use the 200 alt by putting the multiplug on, do i run a third brown wire from the third pin back to the starter positive post?

300tdi and 200tdi uses diffenrent alternator mountings - it is not a direct swap.

The alternator should be wired as such:

B+ (Main output terminal on alternator) to battery positive (or common point on starter)

D+ to charge warning light. D+ is often labelled "IND" on spade terminal alternators.

W+ to RPM counter.

[Mark]

Chadler, if you can fit the 300 alternator, then I would go down that route - ie use the ring terminals and 300 loom. if you end up trying to fit the 300 loom to the 200 alternator, then the multiplug is available from VWP or autosparks I belive, and you can just use the single wire in the 300 loom in place of the pair.

I hope that makes sense?

If you are planning to run an electric winch, it might be worth looking at upgrading to a higher output still - a 300 tdi discovery with aircon has a 120A alternator. You will need to upgrade the charging cable though, maybe doubling up as per the 200 loom. I am running a 120A on my 200 disco.

hth

Mark

[western]

Hmmm, my Marelli alternator supposedly from a air con fitted 300Tdi Discovery is a 100amp unit, if I'd known that 120amp version were about I'd have got one of them instead.

[Mark]

I'll check mine, but I thought it was 120A... I might of course be talking arse, and it is a 100A unit. Either way it's a good upgrade on the 65A or 45A units in consideration...

[BLACK CAB]

You may well find that you will have to rotate the front case 120 degs in order to align with the belt tensioning strap.

IIRC all 300 tdi's are studs and nuts, this is possibly more secure than the 200 TDI plug/wire clip.

Rod

[chadler]

300tdi and 200tdi uses diffenrent alternator mountings - it is not a direct swap.

can you elaborate on the differences? would it be an easy enough thing to modify, or failing that, are there 300 style alternators (preferable uprated output) that use stud connections on the rear that would fit the 200tdi mounting pattern?

[western]

the 100amp Marelli uses stud connections IIRC.

[Kim Horsevad]

can you elaborate on the differences? would it be an easy enough thing to modify, or failing that, are there 300 style alternators (preferable uprated output) that use stud connections on the rear that would fit the 200tdi mounting pattern?

If I remember correctly then the 300 tdi uses a alternator with this mounting pattern:

And the 200 tdi uses a alternator with this mounting pattern:

A direct comparison between the two types can be seen here:

It is, of course, quite possible to make som kind of custom adapter bracket.

The differences between the output terminals - studs or spade terminals - are really only just a minor inconvenience, as long as the alternator itself can be physically mounted to the engine.