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AC Belt Size - 400i (1984)

Discussion in '365 GT4 2+2/400/412' started by SouthJersey400i, May 28, 2007.

  1. SouthJersey400i

    SouthJersey400i Formula 3

    Mar 14, 2007
    1,202
    Romulus, NY (Finger Lakes)
    Full Name:
    Ken Battle
    Can someone look at their AC belt and tell me the size? Or if you know for sure the size that was put on, that should do also.

    I bought a pair of belts from Algar In Philly (F dealer) and they appear to be about 2 inches short in circumference.

    They are not easy to get to, but not as bad as the PS belts, but there is no way these belts will fit on.

    Help please.
    Ken
     
  2. blkprlz

    blkprlz Formula 3

    Mar 24, 2007
    2,158
    Tampa bay
    Full Name:
    Bruce
    Hey Ken,
    Algar in Wynnewood, a nice bunch of people(I grew up in the Valley Forge area up until a few years ago).These are the #'s on my 2 belts, give them a call---if they can't help, I'm sure Dennis McCann out of Ohio can(www.allferrariparts.com}

    Made in Germany Continental 13X710/ A28 /A740 EL
    I'm sure the 13 & 710 are in mm

    Bruce
     
  3. SouthJersey400i

    SouthJersey400i Formula 3

    Mar 14, 2007
    1,202
    Romulus, NY (Finger Lakes)
    Full Name:
    Ken Battle
    Bruce
    Thanks for the numbers. Yes, I agree parts guy at Algar is great.

    He sent me the Conti 13 x 710 and it is impossible to fit. It is clearly about an inch too short in circumference. I am at the full limit of adjustment. I had the Conti belt at a parts store this evening and we measure the Conti belt and it is only 670 to 680 on the metric scale in the shop. How is that possible?! 710 mm is 27.9" and I only measure it to be about 26". Though measuring belt length is a bit problematic.

    I can match the belt with a generic domestic metric size belts. ON my first try I was too big.
    Ken
     
  4. blkprlz

    blkprlz Formula 3

    Mar 24, 2007
    2,158
    Tampa bay
    Full Name:
    Bruce
    Hey Ken,

    Weird!! Your 670/680#'s surely reflect the 1" difference of the 710mm. I would have no problem switching to a Gates or comparable, just be sure cross-section profiles match. AdvanceAuto Guys let me go back to search for the right part w/them---Just tell them it's for your Ferrari--They don't get exotic car owners in their stores often!

    Good luck, Bruce
     
  5. SouthJersey400i

    SouthJersey400i Formula 3

    Mar 14, 2007
    1,202
    Romulus, NY (Finger Lakes)
    Full Name:
    Ken Battle
    Bruce
    I have a good local shop I have been bugging for 10 years for various one-off parts for my Lotus and Cosworth motor. They shake their heads whenever I drop by.

    Last evening we worked out the cross section and selected two sizes to try but both proved too long. One more try and I will have it.

    I'll post the final size when I have it installed, tightened and tested.
    Ken
     
  6. blkprlz

    blkprlz Formula 3

    Mar 24, 2007
    2,158
    Tampa bay
    Full Name:
    Bruce
    Hey Ken, as a suggestion--Cut a piece of string or paper(anything will do) to the 710mm length and wrap it around the sample belt laying on the table to close in on that size.
    Good Luck! Bruce
     
  7. SouthJersey400i

    SouthJersey400i Formula 3

    Mar 14, 2007
    1,202
    Romulus, NY (Finger Lakes)
    Full Name:
    Ken Battle
    Bruce
    That was the first thing I did when the Conti belt did not fit. I have a small tape measure; both it and a string go much farther into the groove than the belt will go. IN spite of that it said the Conti belt was over an inch too short.

    Here are two belts that will work for sure from NAPA:
    - 25-9295
    - 25-9300
    25 is the metric cross section and the two lengths are 29.5 and 30" respectively. Both go on easily and leave room for stretch when tensioned. Two other national parts stores did not carry any of the right cross section belts. An 'A' belt is a standard US profile but it is narrower and has a deeper Vee.

    I am still amazed that Conti miss-marked the belts. German error? PREPOSTEROUS!
    Ken
     
  8. blkprlz

    blkprlz Formula 3

    Mar 24, 2007
    2,158
    Tampa bay
    Full Name:
    Bruce
    Ken,
    German mismarked part--strange! Made note of these #'s in the event--Good deal.
    Bruce
     
  9. SouthJersey400i

    SouthJersey400i Formula 3

    Mar 14, 2007
    1,202
    Romulus, NY (Finger Lakes)
    Full Name:
    Ken Battle
    Bruce
    I know from my plant work that when you have multiple belts for one set of pulleys, you need to use "matched belts". This is like the racers creating stagger with small differences in "identical tires". There are small differences in belt sizes. When I tensioned the belts one is tight to spec or a bit more and the other has a bit of slack but still doing some work. Hopefully the shorter one will stretch fairly quickly and they will equalize.

    I bet those two undersized Conti belts are matched.

    I road tested the car today and all seems fine. The one worry I had was that the AC belts failed because of a bad compressor, but AC is fine. :)
    Ken
     
  10. 4redude

    4redude Formula Junior

    Jan 13, 2005
    674
    Someplace new
    Full Name:
    Brian Keegan
    The factory publications all say 13x710 which is like putting Oprah into Spandex. You should actually try 13x715 belts. They will be a snug fit to get on but will work fine. Seen that movie, know how it ends. ;-)
     
  11. Choptop400

    Choptop400 Karting

    Oct 10, 2014
    85
    Huntington, NY
    Full Name:
    Frank L Caponi
    Installing new belts on 400i. Having difficulty finding the continental belts in NY or on line for that fact.
    I am able to get the NAPA belts 25 9300 ($12.38 each) at local NAPA store. Checking to see if these really work?
     
  12. jacques

    jacques Formula Junior

    May 23, 2006
    830
    Los Angeles/Florida
    I need to check my belts this week. All from NAPA. As I'm sure you've guessed, the last set of ###'s is the length. Just cut the belt(s) and take them to the store and buy two of each. Worked for me. Jq.
     
  13. Choptop400

    Choptop400 Karting

    Oct 10, 2014
    85
    Huntington, NY
    Full Name:
    Frank L Caponi
  14. Part Time

    Part Time Formula Junior
    Silver Subscribed

    Dec 16, 2013
    471
    Port St. Lucie, Fl
    Full Name:
    Gary Shore
    Frank....the slots on the inside of a v-belt are there so the belt can bend around a small diameter pulley. Makes no difference compared to the original.

    Gary
     
  15. Choptop400

    Choptop400 Karting

    Oct 10, 2014
    85
    Huntington, NY
    Full Name:
    Frank L Caponi
    Thanks Gary, that is what I thought. Just like to have someone else in the ship as I go over the end of the earth. LOL Will update when all done for giggles.
     
  16. SouthJersey400i

    SouthJersey400i Formula 3

    Mar 14, 2007
    1,202
    Romulus, NY (Finger Lakes)
    Full Name:
    Ken Battle
    NAPA belts 25-9295 (29'5") and 25-9300 )30") are both okay. However, when you buy the two belts have the shop measure them both on there little sizing gig. There are big variations in size that will not be obvious until you tension them. If they are not a matched set one will do all the work until it breaks or stretches to the size of the larger one.

    You can by a MATCHED SET from McMaster Carr or similar industrial supply house; they sell Gates belts Gates number is Ax28 X Type.

    I think NAPA can order all the small M-series belts. I choose to buy them from a Gates distributor. You order from them and they are drop shipped from the factory in a couple of days.
    Ken
    p.s. I just scrolled up and saw that we had this same conversation back in 2007; one year after I bought my car.
     

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