Hi All,

edit--- title should be " '04 engine swap headaches"

I'm new here but far from new to cars. I've restored several datsun Z cars, Mercedes SLs, and tinkered on a couple BMWs.

Anyway...... I bought an '04 base model with a bad engine. I'm guessing the timing chain tensioner went out, and with some additional bad luck, bent several valves. Pulled the head, it was in pretty bad shape. I found a strong engine out of an '03 that I now have in the car.

NOW I find out the alternator was changed between '03 and '04 -- from a 105 or 110 amp to a 120 amp. The larger alternator has a larger case and does not mount on the '03 block. The '04 wiring is for a Valeo alternator and is 2 wire. Looks like the '03 alternator is a Denso and is 3 wire.

So, now the questions.... is there a wiring adapter kit to connect the 105 amp 3 wire alternator into a Valeo 2-wire system? Or is there a mechanical mounting kit to mount the '04 alternator into an '03 bl0ck?

Thanks!

Glen

 

So, nobody else has had this ...uh.... problem? Anyone?

 

wouldn't it be easier to just look for an '03 alternator?

 

Ill be on the same situation, maybe. I'm doing a 05 jcw into a 03 mcs. As far as I know the block for the base Cooper is the same as the S engine. Ill be interested to know your fix to this.

 

Yeah, the '03 alternator is the direction I need to go. The issue there.... the '04 engine harness is for a 2 wire alternator (Valeo), the only '03 alternators I've found are 3 wire (Denso). I have the Bentley manual, and it shows the differences, but doesn't give pin out detail and what that pesky 3rd wire does.

In short..... if a 2 wire '03 alternator exists, I'd be done..... So now I'm digging around trying to figure out how to connect the 3 wire alternator into a 2 wire harness.

While I think most (if not all) the internals of the 03 and 05 blocks are the same, the alternator mount is definitely different, the 04 alternator does NOT fit on the '03 block. Motor mounts are all the same though... so I have that much going for me.

 

i wonder if this swap issue is just for the natural aspirated cooper.
i looked at part numbers for the supercharged coopers and it listed that my 03 s uses the same part number as the 05 s. it listed for both 03 and 05 s that the alternators are 3 prongs. go to realoem.com to see part numbers. hope that helps.

 

Sadly, I think RealOEM is wrong on this one. They list a 105 amp alternator for the '04 and I know my '04 uses a 120 amp alternator --- 'cause I have it in my hand.

 

i guess this issue is isolated on the natural aspirated cooper.
i just called the local dealer parts department and that my 03 S and 05 S uses the same alternator. the 05 jcw engine that i have is from my wrecked 05 JCW and i don't have the 05 alternator anymore. I'm interested on what you find regarding your issue.

 

Miles -- I think you are correct. The Bentley manual shows only the Denso version on the Super. Guess Mini thought the 105 amps were ample and didn't see the need to change that to the 120 amp Valeo.

And the fun continues.

 

there's got to be someone here that did a project like yours and found a solution. good luck on your project. will follow this thread.

 

I don't know how much time you have, but I have had luck in situations similar to this by just hooking everything up (in your case an 03' alternator) and tinkering about with that 3rd wire haha. It takes forever and can be frustrating but sometimes you stumble upon something that works
Keep us updated!

 

http://www.maniacelectricmotors.com/hiou140ampal31.html
Perhaps this is worth a shot? Maybe ask them about their harness specs.

 

That high power alternator in the same mechanical enclosure is kind of interesting. Saw this a bit late, have a 105 amp on order from Autozone and the 3 pin connector from Mini. I had plans to do what you suggesting in post #11. The 3rd connection goes to the ECU -- I only hope it's an ECU input and not an output the alternator needs for something.

I'm always up for a good experiment!!

Thanks for all the comments -- I'll post how it turns out later in the week when all the goodies show up!

 

Without looking too deep in the manual i did a quick check if its a input vice output. Page 130-6 under performance control on the ECM its listing a alternator output. check it out.

 

Thanks for the pointer -- I read that and does "Generator Output" mean a signal from the alternator or an output from the ECU? I would kind of guess that section to be ECU centric...... Anyway, I'm going ahead with mounting the '03 and leaving the ECU unconnected for the 1st pass. If no luck there, then I'll try my hand at hacking the ECU connector to add in the wire and hope the '04 ECU has that function programmed.

Thanks again!

 

Well, it's official.... I'm dumber than a box of hammers. :-(

Following the Bentley manual on installing the alternator the drawing shows the two bolts to the bottom, single bolt on top. In that case, the 120 amp alternator wont fit. After looking around at some pictures and threads, I see the 2 bolts on the top. Huh.....

When I flip the alternator over, the two top bolts line up with the block mounts, the lower single bolt shares a mount with the water pump. Belt lines up great.

I'm calling this the curse of starting work no a disassembled car... one that I didn't take apart.

Now it's running!! Next challenge is to get the MFE back on and drive drive drive!!


Thanks to all for the help and comments -- you guys rock!

 

Glad to hear that you fixed that car. Yes drive drive drive but don't drive that tranny too hard.......
Ill save my 6 speed for you