'78 GTB Melted alternator belt; new one also squealing | FerrariChat
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'78 GTB Melted alternator belt; new one also squealing

Discussion in '308/328' started by wcelliot, Apr 18, 2017.

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  1. wcelliot

    wcelliot Formula Junior

    May 7, 2004
    577
    Maryland, USA
    Full Name:
    Bill
    #1 wcelliot, Apr 18, 2017
    My reliable driver '78 308GTB's alternator belt began occasional squealing at startup last fall... it seemed as the alternator "kicked in" and the generator light would go off, I had some slippage... but then it would "grab" and everything would be fine. Alternator is putting out good voltage and just a tiny glow from the alternator light when headlamps are on...

    This spring coming out of winter storage the squealing was a little worse, but I knew it was time for a belt anyway. However, I waited slightly too long and on the way back from the local gas station for some fresh petrol, the squealing never stopped and the belt melted down (really amazing... I had heard of this but never actually had to peel a belt off pulleys!). I was only a mile out and got the car home before the temps really started rising. Squeals stopped immediately when the belt went, so I know that was the source of the noise.

    I carefully examined the (likely original) alternator and (ancient) water pump when fitting the new belt. Everything was nice and smooth with no play or signs of leakage.

    However, with the new (Gates) belt on and (seemingly) properly tensioned, I got bad squealing on startup and it didn't go away when the alternator light went off.

    So I'm assuming that I have a bad alternator and/or water pump. Should I do further troubleshooting or just replace both proactively since I know they are both ancient?

    And if replacing both, should I do the two belt conversion I've heard about? And recommended sources for that conversion?

    Thanks for any advice!
    Bill
     
  2. johnhunt

    johnhunt Formula Junior

    Aug 9, 2013
    343
    Washington
    Full Name:
    John Hunt
    #2 johnhunt, Apr 18, 2017
    Just about any shop can rebuild that alternator. It is an inexpensive bosch unit. I'll bet it won't be more then a $100 and probably less.

    Just have it done and see if the problem goes away. If not then onto the slightly more difficult water pump.


    Sent from my iPhone using Tapatalk
     
  3. wcelliot

    wcelliot Formula Junior

    May 7, 2004
    577
    Maryland, USA
    Full Name:
    Bill
    #3 wcelliot, Apr 18, 2017
    Thanks!
     
  4. scowman

    scowman F1 Rookie

    Mar 25, 2014
    2,550
    Scottsdale AZ
    Full Name:
    Stu Boogie
    #4 scowman, Apr 19, 2017
    Tell them it's from a 1978 fiat spider with ac so they don't gouge you. Belt noise is usually a pulley alignment problem.
     
  5. mike32

    mike32 F1 Veteran

    May 13, 2016
    5,961
    Isle of man- uk
    #5 mike32, Apr 19, 2017
    Have a look at the profile of the belt pulleys, they may need changing if they are worn- try a straight edge down the slope of the V
    If it has worked on a single belt all these years why change it. Spin the pulleys to be sure they are running true and you dont have a bent alternator shaft etc
     
  6. Tire Fryer

    Tire Fryer Karting

    Feb 18, 2013
    154
    Farmers Branch, TX
    Full Name:
    Christopher Williams
    #6 Tire Fryer, Apr 19, 2017
    My 80 GTBi had the exact same symptom as yours. Squeal on start up and shredded a belt. I replaced the belt, still had the same squeal. I found if my battery had been on the tender for quite a while and was fully charged, it squealed less, so I removed the alternator and had it tested, it was failing. Like others posted, it is a simple Bosch unit, and mine was $110 bucks to rebuild. I had it upgraded to a 65amp output also, as it was a 55amp unit.
     
  7. kcabpilot

    kcabpilot Formula 3

    Apr 17, 2014
    1,607
    California SF bay area
    Full Name:
    Paul
    #7 kcabpilot, Apr 19, 2017
    An aspect of the two belt theory is that with a single belt, if it goes, you know immediately because your alternator light comes on whereas, with two belts, if the water pump belt goes you don't know until the engine overheats. Plus you have an additional idler bearing to think about. So there are pros and cons, it's not a slam dunk either way in my opinion.
     
  8. Qvb

    Qvb F1 Rookie
    Silver Subscribed

    Nov 9, 2003
    2,848
    Newport Beach Ca.
    Full Name:
    John Dixon
    #8 Qvb, Apr 19, 2017
    I had the belt melting issue and it was the water pump. If both the alternator and water pump spin freely without the belt, I think it is more likely the water pump.
     
  9. wcelliot

    wcelliot Formula Junior

    May 7, 2004
    577
    Maryland, USA
    Full Name:
    Bill
    #9 wcelliot, Apr 20, 2017
    Thanks for all the feedback!!!
     
  10. Rifledriver

    Rifledriver Three Time F1 World Champ

    Apr 29, 2004
    37,100
    Cowboy Capitol of the World
    Full Name:
    Brian Crall
    #10 Rifledriver, Apr 20, 2017
    I agree. Those water pumps have been known to seize momentarily and destroy the belt. Also those belts really need to be tighter than most people feel comfortable tightening them. It was not a good belt drive design and also one of the reasons they have a reputation for pump trouble. The 3 belt system was far better. When you get right down to it the 430 with a spring loaded serpentine was the first Ferrari with a well thought out belt drive accessory system.
     

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