250 Valve Adjusting Screws- Original or Footed? | FerrariChat
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250 Valve Adjusting Screws- Original or Footed?

Discussion in 'Vintage (thru 365 GTC4)' started by jusdriveit, Apr 14, 2012.

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  1. jusdriveit

    jusdriveit Karting

    Sep 11, 2005
    177
    #1 jusdriveit, Apr 14, 2012
    I am looking for the pros and cons to the use of the original valve adjusting screws vs the 911 style adjusting screws which has a swivel foot on the end of the screw where it contacts the valve stem. Please let me know your preference and anecdotes.
    Aloha,
    Mark
     
  2. davehelms

    davehelms F1 Rookie

    Jan 3, 2004
    4,629
    Full Name:
    Dave Helms
    #2 davehelms, Apr 15, 2012
    If you intend to tease redline often, original, they worked pretty well for decades.

    Any valve float will allow the footed type to flip, with the results being a round ball peen hammer on the tip of the stem. Used in a conservative, 500 short of redline manner, with new springs and correct rocker geometry, the Porsche type are fine.
     
  3. prance

    prance Formula Junior

    May 4, 2005
    513
    Agoura Hills
    Full Name:
    morris
    #3 prance, Apr 15, 2012
    Are the footed ones made by Roeloffs? I'm considering them as well.
    I too would be curious of experiences other owners have had.
    Morris
     
  4. jusdriveit

    jusdriveit Karting

    Sep 11, 2005
    177
    #4 jusdriveit, Apr 15, 2012
    I have looked at Roelofs system very carefully and a couple of issues come up
    1) They require more running clearance
    2) They use a smaller roller than the 30 mm stock roller.
    This changes the valve train geometry, as a result I suspect the duration is shortened.
    If someone has some better insight on this i would enjoy discussing it.
    Aloha,
    Mark
     
  5. 246tasman

    246tasman Formula 3

    Jun 21, 2007
    1,446
    UK
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    Will Tomkins
    #5 246tasman, Apr 18, 2012
    Try the ball end adjusters (no foot) from T Rutlands. I think you'll find that the travel is limited so that they can't get jammed if you get valve float.
     
  6. John Vardanian

    John Vardanian F1 Rookie

    Jul 1, 2004
    3,080
    San Francisco Area
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    John Vardanian
    #6 John Vardanian, Apr 18, 2012
    Last edited: Apr 18, 2012
    I just got a standard set from GT Car Parts, along with the jam nuts. Anyone now where these are manufactured, cause the finish and quality appears superb?

    john
     
  7. Motob

    Motob Formula 3
    Professional Ferrari Technician

    Nov 11, 2003
    2,368
    Frederick, Maryland
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    Brian Brown
    #7 Motob, Apr 18, 2012
    The ball adjusters are junk. I have seen the balls come out. The balls also tend to spin around when you insert a feeler gauge in to check the clearance. The ends of the valves have to be perfectly flat (new) for them to work, so you cannot install them on a used valve that has any wear from the original screws.

    Why complicate things when the original screws work fine as long as you use good screws with properly hardened ends that don't wear?
     
  8. 246tasman

    246tasman Formula 3

    Jun 21, 2007
    1,446
    UK
    Full Name:
    Will Tomkins
    #8 246tasman, Apr 22, 2012
    Thanks for this input Brian.

    What sort of mileage would you expect to get from proper new original screws starting off with new valves on a well maintained engine using the full rev range?
     

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