Robs 308 GT4 Clutch Service Adventure Take 2 | Page 4 | FerrariChat

Robs 308 GT4 Clutch Service Adventure Take 2

Discussion in 'Technical Q&A' started by robertgarven, Sep 29, 2018.

This site may earn a commission from merchant affiliate links, including eBay, Amazon, Skimlinks, and others.

Page 4 of 4
  1. Ferrari Tech

    Ferrari Tech Formula 3

    Mar 5, 2010
    1,126
    Georgia
    Full Name:
    Wade Williams
    #76 Ferrari Tech, Apr 1, 2019
    Rob,
    I have had some fit and some don't. The last one I had fit, the one before that did not fit and I used lapping compound to clearance the nut. The nut is softer than the shaft and it works when you need it. I rarely remove the top nut. What I did was make a tool from a clutch disc hub that I can clamp in a vise and torque it there before it goes on the car. I haven't had to do that here at ***************** so I haven't made one here yet, but I am sure I will as I have many 3#8 cars coming through. You said on the phone that only one side had been staked on the old nut, use it again and stake the other side with just a touch of LocTite.
     
  2. robertgarven

    robertgarven F1 Veteran
    Owner

    Feb 24, 2002
    5,269
    Ventura, California
    Full Name:
    Robert Garven
    #77 robertgarven, Apr 2, 2019
    Wade,

    To torque that without rotating the engine (the wrong way), put in all transfer gears, put in reverse, handbrake on and rag in gear teeth??
     
  3. absostone

    absostone F1 Veteran
    Silver Subscribed

    Jul 28, 2008
    9,280
    #78 absostone, Apr 2, 2019
    sound right to me.
     
  4. Ferrari Tech

    Ferrari Tech Formula 3

    Mar 5, 2010
    1,126
    Georgia
    Full Name:
    Wade Williams
    #79 Ferrari Tech, Apr 3, 2019
    S
    Sounds like a plan to me.
     
  5. robertgarven

    robertgarven F1 Veteran
    Owner

    Feb 24, 2002
    5,269
    Ventura, California
    Full Name:
    Robert Garven
    #80 robertgarven, Jun 13, 2019
    Friends,

    I have been busy with the band, so just getting around to working on the Dino. I found a clutch shaft ring nut at Dinoparts that fit perfectly. I torqued both ring nuts down, tapped in the indents, hooked up all the helper springs connections and went to put the transfer gear cover on. As I was torquing the 8x1.25 nuts down two of the studs started to pull out! @#$%!! For a second I was think screw it the others will hold the cover but, hey this is a Ferrari.

    I figure I'll take it apart an put in some timeserts. Turns out all the studs had helicoils inserted!! Anyway one broke and came halfway out and the other one was pulling out but I could not get removed by double nutting... I am hoping Wade or one of you other experts can help me. I have a few questions. BTW I was using hardly not torque on these.....

    Is there a helical removal tool that I can use to take that broken ones out? One pulled out into the cover (see pic)
    Now that it has been drilled out can I still use a timesert? I have never liked helicoils because I used a timesert first and so have no experience with them.
    How do I remove the other stud with the alignment dowel that would not come out double nutted?

    As always thanks in advance for any help. I was hoping to drive this very expensive Dino someday! Hoping there are some help-coil experts here!

    Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login
     
  6. absostone

    absostone F1 Veteran
    Silver Subscribed

    Jul 28, 2008
    9,280
    #81 absostone, Jun 13, 2019
    Sorry for the bad luck Rob
     
  7. 2dinos

    2dinos F1 Rookie

    Jan 13, 2007
    2,780
    #82 2dinos, Jun 19, 2019
    FWIW:
    I replaced clutch recently on my GT4. Put in last ~30 years ago (~20kmi). Reason for doing the job - release mechanism felt "Dry". Anyway, previous clutch action with carefully setup helper spring, and all fresh mechanism bearings etc felt perfect.

    Short story- Hate the feel of this new clutch! All original bits. New everything associated etc. Smooth as can be, but the release action is vague and wimpy. I've been reducing helper spring more and more, still not right. Thinking too that the PP might be to blame. I buy my parts from very solid established sources. I guess, could still be defective?? Thanks for any input.

    How we love them so!
     
  8. robertgarven

    robertgarven F1 Veteran
    Owner

    Feb 24, 2002
    5,269
    Ventura, California
    Full Name:
    Robert Garven
    #83 robertgarven, Jun 19, 2019
    That is what started this whole episode. The clutch felt 100% different than on my 1975. I switched all the parts but
    haven't got it back together yet....
     
  9. 2dinos

    2dinos F1 Rookie

    Jan 13, 2007
    2,780
    #84 2dinos, Jun 19, 2019
    Last edited: Jun 19, 2019
    Do you think there's anything different about the PP? I know the Daytona PP has a higher clamping force, which the 308 doesn't need, and some people use these. I drove a car which had Daytona PP, and the pedal pressure was annoying imho. I also was told years ago, that the Ferrari 308 clutch pack is identical to the Jaguar, but the Ferrari parts were more expensive because Ferrari X-Ray examined because of the higher stresses associated with higher rev's. I'm just suspecting variability in the diaphragm spring / the way it's installed / stamped cover anomalies.

    Slightly off topic - 40+ years ago, I replaced my Fiat X1/9 clutch. It was packed in grey/orange packing which looked identical to stock Fiat parts. The price was ~30% less, it lasted 3-6 months before the PP seized. I got it from a local foreign car parts place that used to pepper areas back in the 70's. I bought the replacement from a dealer and paid the premium. Definitely orig FIAT parts, and this one lasted forever. Point here is the 308GT4 clutch pack I bought was from a very reputable dealer ? PP still could be bad? It works - I mean the car drives, but feels awful. The dealer would probably stand behind it, but hate to hassle it.

    Just had a thought: Wonder if you can find spec on release pressure at the finger springs for the PP? Set up PP on a scale, and devise a way to press down on release spring and check value. AP Racing must have this info?
     
  10. 2dinos

    2dinos F1 Rookie

    Jan 13, 2007
    2,780
    #85 2dinos, Jun 19, 2019
    Just found this from the AP Racing Website.

    For 308GT4

    https://www.apracing.com/product_details/performance_upgrades/special_tuning_clutches/vehicle_applications/ferrari/308_gt_4.aspx

    For Daytona:
    https://www.apracing.com/product_details/performance_upgrades/special_tuning_clutches/vehicle_applications/ferrari/daytona.aspx

    Not quite what I was looking for, but still interesting. I pinged their tech page with this question about vague clamping feel. Curious if they respond, and what they might offer.
     
Page 4 of 4

Share This Page