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300tdi 100 Amp Alternators

23K views 72 replies 23 participants last post by  rdavisinva 
#1 ·
OK everyone... I have my 300Tdi apart to replace the timing belt, get the cooling configuration back to stock instead of the mess the previous owner had in there, and other various stuff... and noticed that my alternator is looking pretty worse for wear. I think most of this was due to the many times I spewed oil and coolant out of the engine trying to get to Alaska last year.

So the short story is I am trying to find the 100 Amp alternator that will fit on a 300Tdi. There are many threads speaking of an Iskra that fits, as well as other strange combinations. But it doesn't seem like any thread has the info you would need to order one.

In the end... does anyone have a *part number* for something that fits? Doesn't need to be LR, just something functional.

:confused
 
#2 ·
I've been pondering the same thing for a spare. I see that there are 3 part numbers out there:
AMR5245 97-98 disco
AMR4248 94-96 disco
YLE101113 ????
But I don't know what the real differences are. Is it just pulleys? I hears the Yle one replaces them all. And something to do with heat shields....but I don't know. So sorry not much help, but I would like to know the answer to the question too. That's all the info I have so far.

Pete
 
#4 ·
The Iskra fits, it's a 100 amps unit, cost around $180 brand new from supplier in FL. If I remember well the ref is in the old thread, but in case it's not I can retrieve seller, price and ref. I did had to swap pulley from old Magnetti, you'll need an impact wrench.
 
#5 ·
Yea me too on no heat shield with the current alternator. As I read it was a 3 bolt or 4 bolt mount on the heat shield but I really don't know what that refers to. So to the point I really don't get what the difference really means.

I think I understand that the smaller 4x mm pulley uses a 1580 mm long belt compared to the stock 1600 length. But I can't confirm that with part numbers and dayco cross reference. I have read that the belt should be smaller with the small disco pulley but looking up oem part codes and their actual lengths just yields the stock lengths, so again it doesn't seem to be conclusive. I imagine it will work with any stock belt.

Argh. Again I don't know. It seems like you can make anything stock disco work....
 
#11 ·
Yup. Will send u picture. What is your email or phone # so i can send u pics.

------ Follow up post added September 22nd, 2012 12:04 PM ------

Pete, i guess neil wants it.

For u though, i have an HS2.8L in parts waiting to be put together!! $6200. I have posted this a few times.
 
#12 ·
Am replacing the alternator on a 300 TDI in the shop and received the replacement today from Dingocroft in UK. It's manufactured by Denso IT - Part DAN 008 12V 100A 06M MSY63341-3210. There is no heat shield, but if the old shield and hardware from the factory unit won't fit am going to have a machine shop make the mounting studs and shield for this new unit. I think without a shield the heat from the exhaust will slowly fry the wires. It also worries me about not shielding the back where the diodes are typically located which are know for being heat sensitive.

Hope this helps.

RDavisinVA
 
#13 ·
There are lots of high output alternators. I can't imagine that there aren't several that fit. You should easily be able to find one that fits the mounting foot, puts out 200 amps at 1750 rpm and costs about $300.
 
#16 ·
100 AMP with heat shield for 300 TDI



We have a 100 amp disco unit with prototype heat shield.

PM for pricing as I won't have it until tomorrow.

For 200TDI the alternator conversion is an easy must to upgrade to 169, 200, or 220 amp output.
 
#15 ·
for posterity, I looked into this as well for my 2.8. The 2.8 comes with a Bosch 60A alternator and the vacuum pump is attached to the back of it, which is a constraint for substitution. Pendy told me if I wanted to go this route, look into seeing if the 2.8 block has the fittings to allow a 300tdi mechanical pump to it, to free it from the alternator. I have yet to pursue this, but if anyone else knows, I'd love to hear about it.
 
#21 ·
Anything that will line up with the belt and mounts can be used. The limitation is the stock wiring harnes as the charge wire is somewhat small. This can be easily over come by simply running a heavy gauge 10 wire from the back of the new alternator to the positive lug on the starter where the cable from the battery comes up in addition to the stock harness wire.

This is the one I used http://www.paddockspares.com/amr4248g-alternator-300tdi-a127i-100amp-denso.html?___SID=U
 
#25 ·
Thanks Doug! Great advice. I will upgrade the cable.

So what amp size for a dual battery set up? Is 100A enough? Is there a 120A that is a direct fit to a 300di?
 
#26 ·
It has nothing to do with the number of batteries. It has to do with the amount of draw that you will see. You need to look at how much load there will be and the duty cycle of the loads.
 
#28 ·
Dual batteries has to do with load as stated by John and Chris. Personally I think dual batteries are a waste unless you run an inverter while camping or have a lot of aux lights on while winching with a large winch. Defenders, especially tdi's require very little from the alternator in stock form. Even with the radio on, wipers on high and lights on high beam the 65amp alternator is sufficient. Some are all about additional capacity for that just in case moment which makes sense for those traveling alone in the desert or in very remote areas etc which we don't have here on the East coast so my perspective is scewed. If you run dual batteries alternator size becomes more about how quickly you recharge the batteries. Keep in mind alternators ratings are @ a specified rpm. Many alternators do next to nothing @ idle and really need to be @ 1200 rpm or higher to make the juice.
 
#31 ·
Between my Icom IC-7000 HF radio (during transmit of CW) and ARB fridge (when running) alone I was looking at ~30 amps.

It seemed like an easy job to drop in the 100 Amp alternator, and it was. Bolt in replacement. Now I just need to find a hand throttle during winching to keep the amps up. I miss the "Tac Idle" switches on military trucks.
 
#32 ·
While installing new intercooler hoses I tore off this inconveniently located inline fuse for my alternator. Two questions: 1. Can a drive around without the alternator fused? I assume it wouldn't charge the battery but are there other damaging effects? 2. Is this really the best way to fuse the alternator or is there a better way? I'm planning an alternator upgrade so that would be the time to fix this if its not done right.
 

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