348 alternator removal & rebuild | Page 13 | FerrariChat

348 alternator removal & rebuild

Discussion in 'Technical Q&A' started by ernie, Mar 12, 2007.

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  1. ///Mike

    ///Mike F1 Veteran

    Dec 11, 2003
    6,097
    Bugtussle
    Glad it’s working again.

    Got the regulator from finditpart$$ and it at least seems to be a real Denso part (although counterfeiters have gotten pretty good these days).
     
  2. Ga68_

    Ga68_ Karting

    Jul 16, 2017
    71
    France
    Full Name:
    Gaetan
  3. dahveedem

    dahveedem Formula 3

    Mar 12, 2012
    1,586
    Maryland
    Full Name:
    David
    I'll post this on the various Alternator posts so it's everywhere.

    For those of us who need the 103mm rectifier, I did confirm with Regitar earlier this week the only difference between the RN-02 and the RN-04 is the size of the stud.

    RN-02 -- 6mm stud
    RN-04 -- 8mm stud

    Both are 103mm and have the 8-50Amp diodes

    so they are both interchangeble by tapping out the stud and putting in the one from your old rectifier.
     
  4. dahveedem

    dahveedem Formula 3

    Mar 12, 2012
    1,586
    Maryland
    Full Name:
    David
    Interesting convo with an alternator rebuilder today. The 105amp version in my car was superseded to a 5071 for the last 4 digits of the part number Mike provided.

    When looked at the BOM for parts...it did list the RN-04 as the rectifier but he found a different voltage regulator... 126000-1500.

    I just put new brushes in, new rectifier new VR. It put out plenty of volts but only about 25 amps on his test bench.

    Maybe his RPM werent high enough?

    Stator looked good.

    Thoughts?



    Sent from my SM-G965U using Tapatalk
     
  5. dahveedem

    dahveedem Formula 3

    Mar 12, 2012
    1,586
    Maryland
    Full Name:
    David
    Anyone put their rebuilt alt on a test bench and see how many amps it was putting out?
    mine with new Denso Reg, new Regitar rectifier and new brushes is only putting out about 20amps.

    maybe a stator issue? anyone have that part number?
    Also some mention in a thread about the windings.. but everything looks good with them at this time.
    I'm half afraid to take her any distance as she'll leave me sitting.

    I've checked all the grounds, even made a new ground wire from Alt to chassis as the other one had some corrosion. No parasitic draw either.

    Help?
     
  6. Mike Wroe

    Mike Wroe Rookie

    Jul 12, 2018
    1
    Full Name:
    David Michael Wroe
    Having had long time problems with the alternator on my 355 spider including multiple recoveries when it left me on the side of the road I took the plunge and rebuilt my alternator insitu using the parts recommended by Ernie only to find that it was still only putting out just over 13 volts as previously so I then trawled through the site and found the thread on 355 alternators and earth straps, back under the car and lo and behold there is no earth strap fitted to my alternator so I made one up out of heavy duty cable and fitted it and bingo 14+ volts so maybe I didn't need to rebuild the alternator after all. Just a warning to other 355 owners to check the alternator earth straps before getting into alternator rebuilds.
     
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  7. ernie

    ernie Two Time F1 World Champ
    Lifetime Rossa Owner

    Nov 19, 2001
    22,574
    The Brickyard
    Full Name:
    The Bad Guy
    Nice job, and good heads up.
     
  8. dahveedem

    dahveedem Formula 3

    Mar 12, 2012
    1,586
    Maryland
    Full Name:
    David
    So i never upated my thread on this?

    Whoops. Will post deets soon but a new stator and rotor fixed me right up.

    Sent from my SM-G965U using Tapatalk
     
  9. ernie

    ernie Two Time F1 World Champ
    Lifetime Rossa Owner

    Nov 19, 2001
    22,574
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    The Bad Guy
    Well get on it son!
     
  10. dahveedem

    dahveedem Formula 3

    Mar 12, 2012
    1,586
    Maryland
    Full Name:
    David
    wow... I'm a bit late.

    303-52003 Rotor 80A-100A --- paid $49.87
    340-52002 Stator 4 Lead -- paid 30.91
     
    ernie likes this.
  11. AceMaster

    AceMaster Three Time F1 World Champ

    Feb 6, 2009
    34,548
    Ontario, Canada
    Full Name:
    Mike
    Better late than never
     
    ernie likes this.
  12. Lolwut

    Lolwut Rookie
    Silver Subscribed

    Aug 21, 2019
    40
    Thanks for the thread. It was very helpful.

    That said, are there any special tricks for refitting the belt? I have the alternator back in but cannot get the belt back on for the life of me. I have the tensioner all the way loose and have tried to run the belt beside the tensioner for some extra slack without any luck. It is the correct belt (Dayco 199826).

    First time I have been defeated by a belt
    Help please!!
     
  13. ernie

    ernie Two Time F1 World Champ
    Lifetime Rossa Owner

    Nov 19, 2001
    22,574
    The Brickyard
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    The Bad Guy
    There where 2 different size belts. Take your old original belt with you to the parts store and just have them match it up. One belt is 774mm long while the other is 776mm long. Chances are you need the 776mm long belt.
     
  14. Qavion

    Qavion F1 World Champ
    Silver Subscribed

    Feb 20, 2015
    11,484
    Sydney
    Full Name:
    Ian Riddell
    Are you sure you're screwing the tensioner in the right direction? I've been told the adjustment is counter-intuitive.
     
  15. Lolwut

    Lolwut Rookie
    Silver Subscribed

    Aug 21, 2019
    40
    Just an update. I ended up undoing the top bolt and pivoting the alternator a bit. I tried this earlier but was more forceful this time and the belt fit. It was then easier to get around the tensioner.

    I would suggest refitting the belt this way for anyone else in the future. Car is running great again!
     
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  16. ernie

    ernie Two Time F1 World Champ
    Lifetime Rossa Owner

    Nov 19, 2001
    22,574
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    The Bad Guy
    Thanks for the tip Sundeep.
     
  17. dahveedem

    dahveedem Formula 3

    Mar 12, 2012
    1,586
    Maryland
    Full Name:
    David
    Hey gents

    Apparently my alternator is fried again according to my indy shop. He said its not putting out enough juice and looks pretty fried upon inspection.

    I had rebuilt the entire thing last date of this post - every part in it.

    How long are you guy's rebuilds lasting?

    Is heat killing it?

    Tia

    Sent from my SM-G965U using Tapatalk
     
  18. ernie

    ernie Two Time F1 World Champ
    Lifetime Rossa Owner

    Nov 19, 2001
    22,574
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    The Bad Guy
    Heat for sure, and then high loads when the radiator fans kick on. I don’t think they are high enough amps to begin with anyway
     
  19. dahveedem

    dahveedem Formula 3

    Mar 12, 2012
    1,586
    Maryland
    Full Name:
    David
    Hey all... have all my new parts for the rebuild except for the voltage regulator and I can't find it anywhere.

    126000-1500
    Anyone have a cross reference for it or know where it can be sourced? I'm all googled out.

    I also thought I used a different VR when I rebuilt it last time..... but I'm getting old and it was 3-4 years ago.
     
  20. dahveedem

    dahveedem Formula 3

    Mar 12, 2012
    1,586
    Maryland
    Full Name:
    David
  21. RC2211

    RC2211 Rookie

    Dec 30, 2018
    39
    Full Name:
    Rodolpho C
    I'm doing my alternator as well
    Thanks for all the info here! Helps a lot

    I found this as today 2023

    Specs and for sale Rectifier # INR736 https://store.alternatorparts.com/partnoin220.aspx
    I bought everything here;
    Denso Alternator Regulator https://www.finditparts.com/products/2379264/denso-126000-0400 - U$ 28,80
    Rectifier INR736 https://www.finditparts.com/products/16977245/wai-inr736 - U$ 58,03
    Brush Holder Assembly https://www.finditparts.com/products/2379112/denso-021620-2720 - U$24,35
     
    Minhwinn likes this.

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