HELP!! Just Discovered A Factory Update On 308 QV Alt/WP Belts

Discussion in 'Technical Q&A' started by Dr Tommy Cosgrove, Jan 11, 2006.

  1. Steve Magnusson

    Steve Magnusson Two Time F1 World Champ
    Lifetime Rossa

    Jan 11, 2001
    Full Name:
    Steve Magnusson
    Yes, adding a "high performance" water pump to the marginal early QV system with a single belt driving the WP and alt isn't a step in the right direction. Is the alternator still rated at the stock 80A, or was it also "upgraded" during the rebuild?
  2. To remove this ad click here.


    NYCFERRARIS Formula 3

    Mar 2, 2004
    Thanks Steve - I kept it stock -- I purchased the autoricambi (the fiat guys) famous 95A alt that they sell for the 124 and checked - it would fit nicely with just a few spacers - but I stayed with my OEM stock Bosch 80A for now.

    I have the early QV single WP/Alt belt run -- I did a lot of research and examination on this matter and this is what I found --- YOU NEED THE GATES 7M975 BELT - the 7M1000 which is OEM spec and what the parts shops will send you was, for me, too long and is hard to tension properly. Fitting the 7M975 solved all my problems. I bought the belt online at Blieber Belts in WV (something like that - I have no affiliation) for less than $20 -- including shipping. I also went to the Gates industrial catalog which has more info on these PolyFlex belts that you could ever imagine. Here is some of what they say and might explain why some belts fail and some don't. Gates is emphatic -- NEVER install the belt by "ROLLING" the belt onto the pulley. They say this will cause invisible damage to the belt that even the most experienced installer will not detect. This internal damage will cause the belt to fail quickly. Also - they caution about the tension -- the tension is very important -- inaccurate tension will cause heat and the belt will fail quickly. They insist on using a gauge and measuring the tension accurately, again they caution against even experienced installers going by feel. They also require periodic retentioning -- this may explain the mystery why the specific tension measurements are located in the 308 owners manual -- I guess we really need to retention the belt from time to time to prevent heat and failure. I used a Gates "Kriket" gauge and set it at 5lb. at point "A" I could not get the OEM spec belt of 7M1000 to tension reliably. For those interested - the Gates catalog has all kinds of engineering specs on pulley alignment and some extensive examination of idler pulleys - that might explain why the Ferrari engineers went with the set-up they did -- not withstanding that they really had limited space to put in something more robust - which is what they should have done.

    This is an old thread and I thank all those before me for their informed discussions and sharing their experience, photos and solutions - it assisted me greatly.

    NYCFERRARIS Formula 3

    Mar 2, 2004
    The Ferrari engineers really had some daring in this design -- that alternator pulley is spinning dangerously close to that hot aluminum water pipe that is only secured by rubber hoses. also the alternator adjustment bracket sits very very close to the spinning alternator cooling fan - the clearances here are sick.
  5. M.James

    M.James F1 Rookie

    Jun 6, 2003
    Worcester, MA
    Full Name:
    New reply, and an update. I brought my car to New England, and had IFS work on it, including adjusting the WP. On the drive home from their shop, I 'lost' my WP belt AGAIN. Same 'slippage', which causes massive friction on the belt. The heat causes it to 'melt', not snap, and the result is a molten hard-plastic 'donut' around one of the pulleys.

    Since this was late on a Friday, I called any shop that was still 'open' and reached Boston Sportscar, who sent a flatbed to retrieve my car. When they had a chance to diagnose my car, they found that upon throttle snap-release, the belt would greatly slacken and 'flap'. This flap would cause the belt to contact a mis-aligned A/C Compressor, whose washer/spacer assembly was incorrect. The impact with the A/C compressor bracket would retard the belt, and cause it to rub/slip on the pulley mechanism. They re-hung my A/C compressor, with the spacers mounted correctly, and it solved the belt problem. I had one other belt failure, caused when a mechanic mis-installed a coolant hose into the path of the WP belt - the belt sawed a hole through the hose before the heat caused the belt to melt-down again....boy, was HE embarrassed. I got a free membership to AAA after that, as I was two miles from his shop but couldn't return due to massive coolant overheat.

Share This Page