96 F355 and Hill Bearing Surprise

Discussion in '348/355' started by yelcab, Dec 13, 2010.

  1. ronrob

    ronrob Formula Junior

    Jan 15, 2007
    Var, S.E. France
    Full Name:
    Ronald Brown
    Great post Paul. Clear and precise. Thanks for taking the time and trouble.
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  3. davehelms

    davehelms F1 Rookie

    Jan 3, 2004
    Full Name:
    Dave Helms
    #27 davehelms, Dec 21, 2010
    Last edited by a moderator: Sep 7, 2017
    The ones that I now weld on all the drive gears for every model. Left un welded I consider them a highly effective replacement valve sales tool. By the time the 360 came around Ferrari learned this was required but on that model they only placed two stitch welds 180 degrees apart from one another. The right idea but with only two welds it leaves too much unsupported material to flex. Learning the proper way to weld these without causing distortion and then finding a plating procedure that had legs, would last and not cause collateral problems..... That has been the latest quest I have been testing for just short of 5 yrs now, how to eliminate rust as a wear factor on the belt thus retaining tighter timing control over the course of the belt life. Some might remember a picture I sent Daniel and he posted a few years back showing how much these belts really wear in the course of a 'normal' life, it is significant. All indications to date show this has been successful and I have now collected a shelf full of gears to weld, re plate and exchange. What's included in a major?

    This concept was justified only after Paul designed, built and offered a bearing of the quality level that the Hill bearings are. I had not even considered the possibility that there was still a 355 running around with the early bearings as in this case. Those have not been available for a good many years and my inability to consider this possibility might have called to question the Hill bearings in some minds. This could not be further from the truth, the Hill bearings are the only choice for this application. My apologies if I left anyone confused on this point with my earlier replies.
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  4. AceMaster

    AceMaster Three Time F1 World Champ

    Feb 6, 2009
    Calling a penalty
    Full Name:
    I agree with FBB - ditch them and put on a brand new set.
  5. yelcab

    yelcab F1 World Champ

    Nov 29, 2001
    San Carlos, CA
    Full Name:
    Mitchell Le
    yes, a new set of belts and bearings went on. So, the exercise is not priceless, it is ... $800.

    And I made an error above. The clearance is 0.5mm and 0.45mm.
  6. mad dog

    mad dog Formula Junior

    Jan 5, 2006
    suffolk uk
    Full Name:
    #30 mad dog, Dec 22, 2010
    Last edited by a moderator: Sep 7, 2017
    Sorry to be dim. I'm confused by measurements of over 4 mm . even the 0.5mm is more than I'm getting - can i confirm this is where we are talking about and as its 0.25 in there does that need increasing? Just a thought - We are all talking mm not inches aren't we?
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  8. yelcab

    yelcab F1 World Champ

    Nov 29, 2001
    San Carlos, CA
    Full Name:
    Mitchell Le
    I did not want it to interfere under stress of the engine running so I took 0.75mm off the brackets and after the installation, i got 0.45mm clearance which makes me feel pretty good.

    0.25mm is technically clearance, but if it were my car, i would be more comfortable with 0.5mm clearance. By the way, it is good for you that you are checking the clearance. Good luck.
  9. fatbillybob

    fatbillybob F1 World Champ
    Consultant Owner

    Aug 10, 2002

    While the pros have known about this for years I think you have the first post on this issue seen by "lay" people. Thanks for posting your pain. In the future you may be credited with saving someone elses engine. Your post is a very important one.
  10. yelcab

    yelcab F1 World Champ

    Nov 29, 2001
    San Carlos, CA
    Full Name:
    Mitchell Le
    Thanks for the good words. Something is bothering me about this. I can't put my finger on it yet so I'll need to think about it some more and take a break over the holidays and then see.

    Merry Christmas everyone.
  11. UConn Husky

    UConn Husky F1 Rookie

    Nov 11, 2006
    Full Name:
    Very nice work Dave, thanks for the explanation!
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  13. berlinetta f355

    Jan 11, 2015
    Full Name:
    Trevor Skutezky
    Excuse my ignorance but I am not clear as to where the bracket has to be machined. I am currently doing an engine out service and have just taken delivery of Hill tensioning bearings. I have not tried yet to install them as I am also changing the drive pully bearings and the oil pump chain tighteners. All that has to go back together first. Please advise what clearance is being referred to and what may need machining.
  14. Ricambi America

    Ricambi America F1 World Champ
    Sponsor Owner

    Early 355's (1995) used tensioner bearing 158157 which was replaced by bearing 167464. Those two bearings are not identical, and have the dimensional differences. When Ferrari released 167464, it advised (or maybe mandated) that during installation on 158157-equipped cars, a new tensioner bracket kit was needed to solve clearance issues. The bracket kit 70000973 was basically a new tensioner bracket plus a washer that moved the bearing 1.5mm away. This 'gap' was critical, because the new bracket itself had a winglet that interferes with the bearing otherwise.

    Whether you use a Ferrari-supplied bearing 167464 or a Hill Engineering PT355, this issue remains. Either of those two bearings must have the clearance checked during installation. If your bearing scrapes, seizes, or rips the belt to shreds, it'll be a lousy holiday season.

    I think I've got these photos right --- they're so old I had them on my TRS-80.

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  15. surfwolf

    surfwolf Formula Junior
    Silver Subscribed

    Oct 14, 2012
    Bethany, OR
    Full Name:
    Michael Wolfe
    Thank You Daniel! You really are a wellspring of knowledge for the older Ferrari's. You have helped me numerous times with advise/recommendations on parts for my 1995 348 Spider. Do you miss having your 348?

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