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Technical 8BA & 39 trans questions

Discussion in 'Traditional Hot Rods' started by cederholm, Nov 16, 2018.

  1. cederholm
    Joined: May 6, 2006
    Posts: 1,621

    cederholm
    Member

    I have just finished rebuilding a '53 8BA and have it on a dolly-stand the allows me to test fit other parts. Can I attach a 39 transmission to it WITHOUT supporting the trans - or is that just dumb?

    Also, what clutch size would you use? This combo will go into a full-fendered A. The 8BA came out of a truck and the flywheel looks to have had an 11" clutch. Should I keep that? ....and lastly, should the flywheel be lightened?

    Thanks,
    Carl
     
  2. Well Carl, it seems to me that once you fully bolt up the Trans it will be supported just fine. If you have an 11" clutch, run it. No, a flywheel does not "NEED" to be lightened. If you balanced the motor while doing the rebuild, it and the P.P. should have been part of that job.
    The Wizzard
     
    Black Fifty likes this.
  3. Wizz,
    Pardon my ignorance, but is "P.P." referencing pressure plate?

    Thanks.
    Mike
     
    barrnone50 likes this.
  4. Correct;
     
    Black Fifty likes this.

  5. Thank you. I didn't realize that the disc and pressure plate would be part of that final balancing. That's why I joined the HAMB! ;)
     
  6. tubman
    Joined: May 16, 2007
    Posts: 6,045

    tubman
    ALLIANCE MEMBER

    I think an 11" clutch might be a bit much for an 8BA in an "A". Opinions vary, but they can be hard on the left leg. I would seriously consider going to a 9 1/2" unit from a passenger car or a 10" truck unit. The car flywheel should be easy to find (I have a couple just laying around myself) and you would end up with a better balanced power train. Not to say the 11" won't work out, but a smaller clutch might make life easier.

    Oh yeah, the pressure plate should be part of the balancing, since it is fixed in position to the flywheel. The clutch disc, however, rotates with the transmission main shaft, so you will just have to hope that it is properly balanced as is. I am sure all quality units are.
     
    Hnstray and Black Fifty like this.
  7. Petejoe
    Joined: Nov 27, 2002
    Posts: 11,230

    Petejoe
    ALLIANCE MEMBER
    from Zoar, Ohio

    I have an 11” in my flathead pickup. I just had them install the lightest springs available for the pressure plate. Works perfectly.
     
  8. tubman
    Joined: May 16, 2007
    Posts: 6,045

    tubman
    ALLIANCE MEMBER

    Was this an expensive procedure? I probably wouldn't have thought of it, because I would want a new clutch assembly in a car I was building. I believe the smaller clutches cost less and have significantly less rotating mass. As I said in my original post "Opinions vary". Finally, a pickup is a much different animal than a Model "A". I stand by my advice to the O/P.
     
  9. oj
    Joined: Jul 27, 2008
    Posts: 6,312

    oj
    Member

    You'd think the 11" with greater contact area would need less pressure than a smaller wheel. It is pounds per square inch, the 11" would have greater inches. I am in the same point in my build and hopefully others will clarify.
     
  10. Petejoe
    Joined: Nov 27, 2002
    Posts: 11,230

    Petejoe
    ALLIANCE MEMBER
    from Zoar, Ohio

    No not expensive at all. Found a nearby shop who rebuilds them.
     
  11. 19Fordy
    Joined: May 17, 2003
    Posts: 7,517

    19Fordy
    Member

    Please post a photo of what your dolly/stand looks like to aid in answering your first question.
    11 inch clutch and PP is overkill. Go with 10 in. I am using a 50 Merc 10 in. clutch and PP and 50 merc flywheel and bellhousing in my 40 Ford that has an 8BA block. A 39 trans. will bolt up to it. Go over to Fordbarn as this has been discussed there plenty of times.
    Be sure and read all this plus links.
    https://www.jalopyjournal.com/forum/threads/need-help-8ba-in-40-coupe.1060915/
     
    Last edited: Nov 16, 2018
  12. I don't get it. If he has a good 11" clutch, flywheel and pressure plate why not use it? Over kill and Not necessary, how is that. Works to good maybe? Why should he spend more $$$$ just to get less clutch? To much pedal pressure, might mean it's time to go to the Gym a little more often. Maybe that's why they came out with that Flat-O-Matic pussy thing.
    The Wizzard
     
    LWEL9226, barrnone50 and 504640 like this.
  13. thirtytwo
    Joined: Dec 19, 2003
    Posts: 2,641

    thirtytwo
    Member

    I run a 9” clutch in my 32 roadster that was 0 balanced to the flywheel , it was a typical rebuilt off the shelf clutch, it slipped in 3rd gear , I sent it to soutland clutch in sandiego they put heavier springs in it and better lining on disc, works perfect now

    The bigger the clutch the more reciprocal weight, depending on car I would go small as you can obviously a 9” clutch probably wouldn’t be happy on a Merc , but my little car works great

    I have stock pedals /geometry and can still push pedal in with my arm... I don’t know what all this gym talk is
     
    Last edited: Nov 16, 2018
  14. Fortunateson
    Joined: Apr 30, 2012
    Posts: 4,546

    Fortunateson
    Member

  15. 19Fordy
    Joined: May 17, 2003
    Posts: 7,517

    19Fordy
    Member

    If you do go with the 11 inch clutch you need to use the cast truck bell housing that came with it.
    Be sure to use the correct starter plate.
     
    deucemac likes this.
  16. 51504bat
    Joined: May 22, 2010
    Posts: 3,396

    51504bat
    ALLIANCE MEMBER

    Thanks
    If you're using a stamped steel 1/2 bell from a Merc to attach the 39 trans to your 8ba you can't use an 11 inch clutch. If you have a cast iron 1/2 bell from a truck you can use an 11 inch or smaller clutch.
     
    deucemac likes this.
  17. cederholm
    Joined: May 6, 2006
    Posts: 1,621

    cederholm
    Member

    Really great into guys - thank you!

    For clarity, I have the cast iron truck 1/2 bell and starter plate. If used, the flywheel could use a resurfacing, the pressure plate would need to be rebuilt and the clutch needs replacing.
     
  18. Fortunateson
    Joined: Apr 30, 2012
    Posts: 4,546

    Fortunateson
    Member

    With an 11" you wouldn't need to go to the gym!
     
    cederholm likes this.
  19. tubman
    Joined: May 16, 2007
    Posts: 6,045

    tubman
    ALLIANCE MEMBER

    He has said he has an 11" truck flywheel that needs re-surfacing and a used pressure plate and disc that need rebuilding. If that's the case, he can save a bunch and have a more satisfactory drive train by getting a car flywheel and a smaller clutch. If I had a good flywheel and a new complete 11" clutch assembly, I might use it, but I wouldn't spend anything rebuilding it.
     
    cederholm likes this.
  20. cederholm
    Joined: May 6, 2006
    Posts: 1,621

    cederholm
    Member

    That was my line of thinking.

    Thanks,
    Carl

     
  21. V8 Bob
    Joined: Feb 6, 2007
    Posts: 2,818

    V8 Bob
    ALLIANCE MEMBER

    You could also check to see if a diaphragm replacement pressure plate is available that uses that Long bolt pattern. This should be cheaper than rebuilding the 11" Long, as well as requiring less pedal effort.
     
    Last edited: Mar 20, 2019
  22. speedshifter
    Joined: Mar 3, 2008
    Posts: 312

    speedshifter
    Member

    I run 13lb alu flywheel & 9" Long press plate modified 324 Olds engine 39Ford trans 3.10 rear 31" tires 2400lb roadster. Guaranteed it does not slip& the instant engine acceleration when revd up in neutral sure sounds cool! Greg
     
  23. speedshifter
    Joined: Mar 3, 2008
    Posts: 312

    speedshifter
    Member

    Had Ft Wayne Clutch rbld press plate. Can not remember if they installed heavier springs, have put 15000 miles on clutch since rbld. Works perfect, could not be happier Greg (see above post)
     
  24. PHIL COOPY
    Joined: Jul 20, 2016
    Posts: 409

    PHIL COOPY
    Member Emeritus

    Had clearance problems with an 11".....went to a 9 1/2...
     
  25. rusty valley
    Joined: Oct 25, 2014
    Posts: 3,157

    rusty valley
    Member

    11" truck clutch is...well...for a truck. get rid of it. no need to try and spin all that extra weight
     
  26. Flathead Dave
    Joined: Mar 21, 2014
    Posts: 3,637

    Flathead Dave
    ALLIANCE MEMBER
    from So. Cal.

    Curious...What was the cost of your rebuild?

    Sent from my SM-G930T using The H.A.M.B. mobile app
     
  27. cometman98006
    Joined: Sep 4, 2011
    Posts: 223

    cometman98006
    Member

    The 11 inch clutch works great, had one on my 34' 5 window but I would recommend having the clutch / flywheel assembly balanced. I didn't and mine came apart at a little over 100 mph drag racing Thank goodness I had built a scatter shield that worked.
     
  28. speedshifter
    Joined: Mar 3, 2008
    Posts: 312

    speedshifter
    Member

    It costs a little more to have Ft Wayne Clutch rebuild your press plate than what it costs for a new China press plate, but in my opinion you then have a product that is so much better there is no comparison. Greg
     
    rusty valley likes this.
  29. cederholm
    Joined: May 6, 2006
    Posts: 1,621

    cederholm
    Member

    Dave, I'm sorry I'm just seeing your question now. I forget the exact amount but i think it was around $200. Bearing, bushing, syncros, all my gears were good. ...Check with VanPelt, all my parts came from him.

     
    Flathead Dave likes this.
  30. Flathead Dave
    Joined: Mar 21, 2014
    Posts: 3,637

    Flathead Dave
    ALLIANCE MEMBER
    from So. Cal.

    For the rebuild of your motor?
     

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