348 Alternator Pulley

Discussion in 'Technical Q&A' started by Texas348, Aug 10, 2004.

  1. Texas348

    Texas348 Rookie

    Aug 10, 2004
    lookng for a alternator pulley for an AC Delco alternator 5 groove 2" diameter.
    This needs to be 2" so it's smaller then the stock one.
    We show a discharge at idle and as soon as we go up in rpm we get a positive result. Thinking of fixing the problem with a smaller pulley. Anybody else have had this problem ? The car is a '91 348TS
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  3. Miltonian

    Miltonian F1 Veteran

    Dec 11, 2002
    Milton, Wash.
    Full Name:
    Jeff B.
    The stock 348 alternator should be perfectly capable of keeping the battery charged when the engine is running at idle. If it's discharging, something inside isn't right, or it isn't grounded properly, or whatever. A smaller pulley will make it spin faster, but on an engine that can turn almost 7500 rpm, the alternator is going to be spinning awfully fast. I think you should take the alternator to a GOOD shop and have it bench tested. It can easily be rebuilt with common AC/Delco parts if they find a problem. Just my opinion.
  4. 348 Turbo

    348 Turbo Formula 3

    Jul 17, 2002
    well said.
  5. Texas348

    Texas348 Rookie

    Aug 10, 2004
    Thanks for the comments. This was actually done, and even the alternator has been upgrated to put out 140 watts, but it is still discharging at idle. What could be the cause ? Anybody know what new Delco (part #) replacement alternator can be used ?

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