Thread: Alternator changover

ALT on a V8 is on the right side.
ALT on 300 TDi is on the left is.

as you are a sparky by trade,

can you get a Bosch 120 or 100, that will fit on the left??????????????

I have no idea. I got a bracket cut, and I'll post up pics of the change-over. It's not as elegant as I'd like (though the bracket I got made is extra spiffy), but it does the job.

In terms of fitting a 120A 12121A to a TDi, well, I'll need a 300TDi to look at for a day or so. There are quite a few universal alternators (which is what a BXU12121A is) that have different mounting capabilities and different amperages, ranging from 85A and upwards. It's just a matter of finding what'll fit in the hole, then pulling your hair out for a few days! I do recommend bosch for alternators. They're the good stuff as it were.

Relay, did you consider Ford (or like) (Bosch) for the V8? I reckon PhillipA has done such a beast and there is a fair bit of shared info in various spots.

Could you share the reasons for heading the way you have?

Cheers

Pete

It's true, Ford units are fairly stable. Worldwide there are 'x' amount of alternator manufacturers. Of the x amount of manufacturers I find coming into the workshop the most likely and cost effective rebuild is bosch. The rest are normally just replace replace replace. For instance, your basic bosch reg (re60) costs around $40. Your basic Mitsubish reg costs $120. I haven't priced a delco reg in quite some time, but I doubt they're much better.
Not to mention that bosch normally keep an across the board product procedure. This means they have about 10 different regulators that suit all their alternators. Mitsu, delco and their likes have literally 100s. You order one, and the mounting hole might be 3mm out but that 3mm is enough to make you want to pull your hair out.
Parts for bosch are just easier to get. They dont go obsolete at the 15 year old mark. What bosch made 40 years ago, they are still making today. And in the long term interest of my county, I like that.
Bosch sizing on their alternators also has a very large bonus when fitting aftermarket to a car. This actually works on a lot of alternator manufacturers, but bosch, so far as I've found, have 3 common sizes of rotors (the bit that spins in the middle). This leads to 3 common sizes of brackets. When I bought the 12121A I knew immediately that if it didn't in the hole, due to it's larger foot, that I could find an old style Bosch off a Ford that had a front and back foot and rip the innards out and change them over. I didn't have to do this, but it was an option open to me, and when fitting something that's not exactly right for the job, you need as many options as you can get.
Why I went for the 12121A? I like it's performance curve. It's peak is at 3500RPM. Yeah, okay, so that's fairly high. I sized the pulley to be roughly 1/3 of the crank. (I say roughly, because it's the biggest pully you can get). This means I am getting maximum output at -idle-. I get a little more than that as I move up through the rev-range, but I know that I'll always have 120A capacity for charging my battery, running my spotties, fridge, laptop etc etc. This alternator is going to have an easy life, hence go the distance.

Sorry, if that's a bit long winded.

I've just replaced the alternator on my Disco (300tdi) with the new 100A Marelli one (turned out to be unecessary but that's another story). I was considering buying this one on Ebay.

Discovery Tdi 300 Range Rover 2.5Td, 2.5Tdi Alternator - eBay, Land Rover, Car Parts, Cars, Parts Vehicles. (end time 06-Apr-09 08:25:39 AEST)

Its 140A and was only going to be a little bit dearer (~$360) than the 100A one. I think it's a better option than modifying one that doesn't suit the engine.

Paul

Having just gone through 3 weeks searching for starter motor brushes out of a Marelli I'm kinda hesitant to fit them. Parts supply in Australia is pretty poor. I ended up going after market alternate design starter. It's great thus far.

But yes, if you had a rover that suited that alternator I can understand getting that alternator provided you can get replacement/repair parts for it. I hate searching for parts and not being able to find them!

Bosch is a good idea. I ended up replacing the MM unit on my 300TDi with a Bosch off a Statesman and a couple of brackets off a 40 series diesel 'cruiser. That way I can get bits wherever. Also by-passed that damned fan hub bearing while I was there and put a big lecky fan on.......

I Know you're a sparkie but for the benifit of those who aren't and are contemplating a bigger alternator...

be wary of you're charging rig if you go a massively uprated alternator and for those of you with diesels + aircon + belt drive power steering pumps be wary of the potential extra load your putting onto the belt and balancer.

in normal day to day applications its nothing to fret about BUT...

if you wind up with 1 (or more) nearly dead flat batteries or a short across something thats unfused the alternator will be trying to put out maximum amps until something gives up or the battery takes enough charge that the amps rate on the alternator can drop off. If your wirings not up to it (and IMHO I wouldnt trust the wiring on most landys for a real 55A@12V for anything more than about a minute)