F355 alternator rebuild update, with part numbers.

I bought Denso alternator parts from Nippondenso (Denso)Alternator Parts. A lot of info on their website (and nice pictures).

 

It gets mighty hot down there. Over 18 years of ownership I have rebuilt my alternator twice.

I also had the “sense wire” fail. (Post #96 in this thread, and others re. how to fix that)

One other thing I highly recommend, but rarely see mentioned is to repack the alt bearings with a quality grease. The first time I rebuilt, the bearing grease looked like dried out candle wax. The second time, the grease was still viable, but tired. Definitely worth doing every 10-years-or-so.

With a little bit of TLC I think these alternators can be maintained indefinitely.

 

It seems that Denso in California might have miss led Regitar on the part VRH2005-18a. I will have a definitive answer soon, but I didn't want anyone to buy that 18a over the VRH2005-4a because that might be the one for my alternator as well. The difference has to do with a clutch function I believe.

The 355 NipponDenso 140 amp would not fit in my car and seems to require a new upper bracket pn 149627. Anyone rebuilding the 155785 101211-5071 might want to consider that upgrade seeing how you can still buy them from Ferrari part shops, and the rebuild kits are strait forward.

Check your sensing wire. Several stooges have mentioned this, and it is important. My sensing wire was Red coming from the green plug and attaches to the B terminal of the Alternator's 8mm post. My unit got hot and some cracks appeared in that wire that I didn't see the first time I rebuilt the alternator. That caused a short that could kill a good regulator. Pop!

Regitar has gone above and beyond to help find a solution. They had one of their engineers in my area and he came over to help me trouble shoot, so I'll be calling them first from here on out.
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pn 155785 , 101211-5071 Smaller NipponDenso. Ferrari 348

Replacement parts used.
VRH2005-4A Regulator (Regitar)
INR739 Rectifier (Transpo)

Alternator is back up and running. 14.1 amps

Pro tip. Getting the belt on is easy if you deal with the tensioner last. Engage the larger pulley on the block first, then the smaller pulley on the Alt while bypassing the tensioner pulley. The tensioner is simple to get engaged at that point. The lack of groves makes sliding the belt into place much easier than the grooved Alt pulley.

I added an extra ground strap and made a carbon fiber oil shield. Dripping oil will damage these alts.
Be sure to double check the Sensor Wire that runs from the plug to the B+ terminal of the Alt. I had a ground fault short and was able to fix it.


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