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F355 alternator rebuild update, with part numbers.

Discussion in '348/355' started by jm3, Oct 10, 2006.

  1. jm3

    jm3 F1 Rookie

    Oct 3, 2002
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    Ok! This is a continuation of 2 threads I started about my adventures in improving the reliability of the F355 alternator. Read these linked posts for background if you desire.

    http://www.ferrarichat.com/forum/showthread.php?t=119436

    http://www.ferrarichat.com/forum/showthread.php?t=122889

    I will be making a how-to on this, I took pictures. I will post it in a reply.

    So, to make a long story short, I have successfully improved the F355 Nippondenso alternator. It would have taken one day, but I was sent on a wild goose chase by a defective-out-of-the-box regulator.

    The parts to buy are:
    A regulator, brand name Regitar, part number VRH2005-4A
    A rectifier (optional), which needs a minor mod, Regitar RN-02

    The only place I found that sells them online is
    http://www.holcombedirect.com/browse.cfm/2,55.html

    The defective part I bought was a Transpo IN220, and during my visit to the alternator dyno, they told me that they had occasional trouble with Transpo (assembled in Costa Rica) and had the best results with Regitar (says made in USA on the box fwiw)

    Dyno of totally stock alternator was 13.6 volts at 139 amps for 5 minutes.
    Dyno of improved alternator was 14.1 volts at 161 amps for 5 minutes.

    The gains are more from the regulator than the rectifier, we tested both.

    The goal however is increased reliability. The VRH2005-4A regulator has some features that the stock one does not have in terms of circuitry to prevent shorts or failure when confronted by a battery, belt or wiring problem. The RN-02 rectifier, which is where the diodes turn AC into DC, is very heavy duty. The new rectifier is all copper instead of steel, welded diodes instead of soldered, thicker mount for the battery stud. The 6mm battery stud from the new regulator needs to be replaced with the 8mm stud from the original rectifier. This is reversible for future concours, where the rectifier part numbers must be original.

    I also replaced all the tiny cheesy screws with allen bolts, which made life much easier. They are all 4mm x 0.7 pitch, and I needed 3 for the regulator 5mm long, 4 for the diodes 5mm long, and 2 for the regulator case at 20mm long. The local hardware store didn't have 5mm allens, so I shortened some 10mm ones on a sander.

    The guys at Leo’s electric were VERY impressed with this alternator.

    I will post a how-to for those who need it in a few days hopefully.


    JM
     
  2. Jeff Pintler

    Jeff Pintler Formula Junior
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    Jul 20, 2005
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    Thank you very much for documenting this and finally fixing this problem. Kinda makes you wonder why the dealers keep throwing factory alternators at the problem, at what, $1000 a pop? Again thank you.

    Jeff Pintler
    89 348tb, 86 TR
     
  3. gothspeed

    gothspeed F1 World Champ

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    Great post, this needs to be on the front page :D
     
  4. ernie

    ernie Two Time F1 World Champ
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    This is good to know about the parts.

    I tore apart the alternator out of my 348 last week because it left me stranded on the side of the road. What was weird was, when I took it to the alternator shop they tested it on their bench and the stupid thing was putting out 14.4 volts. I took it apart thinking it was bad brushes and those things were almost new. It also has the Transpo IN220 regulator in it. SO maybe that is the problem. But what the guy at the shop told me was that, these things aren't hit or miss. Kind of like a light bulb, there is no in between, either it works or it doesn't. So on his advice I put it back together and no problems, go figure. Maybe it was something with the belt?

    Whatever the case I'm glad to see you found some better parts. If I do need to put new guts in it I'll use those. What was the modification that you need to do to the recitfier?
     
  5. ernie

    ernie Two Time F1 World Champ
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    So that they can make a butt load of money. I asked the guy at the shop how much it would have cost me for new brushes, regulator, and rectifier, and he said about $60 for the parts.
     
  6. 285ferrari

    285ferrari F1 World Champ
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    Sep 11, 2004
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    I agree with Goth---this needs to be in a Sticky titled 355 parts/cross reference part numbers---I think I suggested that a month ago...

    http://ferrarichat.com/forum/showthread.php?t=125444


    Can a MOD please make this happen?? I think it will greatly help the 355 guys around here. The 348 guys as well as the 308/328 guys have them.

    The part fixing or mentioning should be in the title, that way anyone can scroll thru until you see what you may need.

    I will volunteer to do this myself---someone give me the POWER!!!!!
     
  7. f355spider

    f355spider F1 World Champ
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    Watch out Ernie. I buddy of mine had a similar recurring problem in his 94 348 spider, and pulled the alternator out a couple times and always tested fine. On the final time, he had them test it for 15 minutes....bingo! The voltage dropped off...the regulator would fail after it heated up some. New regulator, and all is well.
     
    geoffmc348 likes this.
  8. No Doubt

    No Doubt Five Time F1 World Champ
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    Sweet!
     
  9. f355spider

    f355spider F1 World Champ
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    BTW, the regulator listed, is no longer posted on the web link provided....
     
  10. No Doubt

    No Doubt Five Time F1 World Champ
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  11. jm3

    jm3 F1 Rookie

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    The 355 alternator, and I believe the 348 have a larger stud where the battery cable bolts up. It is 8mm diameter as opposed to the 6mm stud on 99% of other cars. There is a direct bolt-in regulator, INR 736 that is actually for a Honda Accord. The Transpo INR736 and equivalents have an 8mm stud, but are the same "grade" as the stock regulator, with the crimped (as opposed to welded) diodes.

    There is no "heavy duty" rectifier for the Accord, therefore no heavy duty rectifier with an 8mm stud. The Regitar RN-02 is heavy duty, with a 8mm stud that is machined down to 6mm to fit other cars. I pressed it out with a small hammer (into a 14mm socket) and replaced it with the solid 8mm stud from the stock Ferrari alternator. This took 2 minutes.

    It is still working perfectly, and I will do a how-to-page when I get less busy.

    Jay
     
  12. f355spider

    f355spider F1 World Champ
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    Actually that elreg site is not relevant, as JM3 is trying to stay away from the oem Denso part, and found the Transpo part he tried to be defective right out of the box. Specifically, it sounds like we need to use EXACTLY what he is recommending, the Regitar VRH2005-4A.

    I know you mean well, but your haphazard posting of irrelevant links only confuses and misleads the thread, rather than helping. If you have a specific, and direct link to something, then by all means, add it. But posting links to sites you have come across, without verifying that they have the part or not, does not really contribute to the knowledge base.
     
  13. ernie

    ernie Two Time F1 World Champ
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    ROCK ON!

    My alternator seems to be working just fine right now, but if it leaves me on the side of the road again I'll DEFINATELY be doing this upgrade. I think I'm gonna buy the parts and have them waiting on the side lines, if yaknowadamean. ;)
     
  14. f355spider

    f355spider F1 World Champ
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    I'm of the same thought...for the $40 or so investment, well worth having the parts on hand. Seems the alternators are otherwise robust....just the damn regulators that fail all the time. I will try calling the company listed in JM3's link later next week and see if they still stock the two parts.
     
  15. jssans

    jssans Formula Junior

    Jun 1, 2005
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    I just rebuilt my alternator using the info in these posts. Rectifier & regulator replaced for CHEAP($40)! I would like to add that I rebuilt the alternator without removing it from the car. If you have a right angle screwdriver it can be done.
     
  16. f355spider

    f355spider F1 World Champ
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    Josh,
    Can you post the sources for the parts?
     
  17. ernie

    ernie Two Time F1 World Champ
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    Dave,

    Just go to any good alternator shop and give them the part numbers. They'll be able to get them for you. Just don't tell them what they are going in.
     
  18. ernie

    ernie Two Time F1 World Champ
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    WOW! Was that for both, or each?
     
  19. jssans

    jssans Formula Junior

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    for both... 4real! (shipping included)
     
  20. ernie

    ernie Two Time F1 World Champ
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    DOUBLE WOW MAN!!!

    Well then I'm with Dave, what's the source? Cummon, fess up.
     
  21. ernie

    ernie Two Time F1 World Champ
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    RIGHT ON JOSH! Sweet find.

    I was looking on the site and it seems that the rectifier with the correct size bolt (8mm), or battery post, is part number RN10. The one that I used was RN02 and it had the 6mm bolt. But now we know which one to order the next time around. Heck, I may even order one anyway. Again excellent find, and thanks for sharing!!!!
     
  22. jssans

    jssans Formula Junior

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    #23 jssans, May 22, 2007
    Last edited by a moderator: Sep 7, 2017
    Yeah, I used the RN02 & used new nuts. RN10 & use the old nuts would be easier. But why in the description does it say "W / HOLE" & the RN02 description doesn't. I'm sure it'll work. It just worries me.
    Image Unavailable, Please Login
     
  23. ernie

    ernie Two Time F1 World Champ
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    I don't know? Maybe we should give them a jingle and ask?
     
  24. f355spider

    f355spider F1 World Champ
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    What is the difference between the 4A and 4DG? Something about the LRC according to Holcombe...
     

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