Distributor advance question | Page 2 | FerrariChat

Distributor advance question

Discussion in 'Technical Q&A' started by Sledge4.2, Dec 20, 2013.

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

  1. Sledge4.2

    Sledge4.2 F1 Rookie

    Oct 19, 2007
    4,789
    Marin
    Full Name:
    Geno
    #26 Sledge4.2, Dec 24, 2013
    Last edited by a moderator: Sep 7, 2017
  2. Steve Magnusson

    Steve Magnusson Two Time F1 World Champ
    Lifetime Rossa

    Jan 11, 2001
    26,932
    30°30'40" N 97°35'41" W (Texas)
    Full Name:
    Steve Magnusson
    That seems a reasonable arrangement. You are, maybe, still not to the point of even worrying about this issue (a few degrees shouldn't make a huge difference compared to the runability problem that you have now). Once you get it working, you can always set it without vacuum, to X deg, and then see what happens when you connect the vacuum.
     
  3. stuartlarman

    stuartlarman Karting

    Feb 17, 2009
    57
    Tucson az
    Full Name:
    stuart larman
    Have you tried putting a bottle of gas 'drier' into the tank; you may have some water in there.
     
  4. Sledge4.2

    Sledge4.2 F1 Rookie

    Oct 19, 2007
    4,789
    Marin
    Full Name:
    Geno
    #29 Sledge4.2, Dec 28, 2013
    Last edited by a moderator: Sep 7, 2017
    I set the initial static timing per the WSM, lining up 13 degrees timing mark on the crank with #1 in TDC, the put the distributor rotor pointed dead-on with the mark on the distributor housing.

    Then I started it up and timed it while running, with the vacuum retard connected. Then I stopped the motor, rotated the flywheel back to initial timing and took this picture:
    Image Unavailable, Please Login
     
  5. Sledge4.2

    Sledge4.2 F1 Rookie

    Oct 19, 2007
    4,789
    Marin
    Full Name:
    Geno
    #30 Sledge4.2, Dec 28, 2013
    Last edited by a moderator: Sep 7, 2017
    Then i repeated the same procedure with the vacuum retard disconnected, and took this picture.


    With an addition 10 degrees of advance, the rotor moves ever further from the hash mark.

    Car runs like crap without the vacuum advance connect.


    Seems like i have a phasing issue, but would be interested in any thoughts.
    Image Unavailable, Please Login
     
  6. 2NA

    2NA F1 World Champ
    Consultant Owner Professional Ferrari Technician

    Dec 29, 2006
    18,221
    Twin Cities
    Full Name:
    Tim Keseluk
    Reposition the pickup to get things lined up.
     
  7. Steve Magnusson

    Steve Magnusson Two Time F1 World Champ
    Lifetime Rossa

    Jan 11, 2001
    26,932
    30°30'40" N 97°35'41" W (Texas)
    Full Name:
    Steve Magnusson
    +1 -- or move the 8?-point "star" wheel on the shaft relative to the rotor. How is the star wheel attached to the shaft/rotor? Does it have a bolt pattern that is not a divisor of 8 that can be assembled "wrong"? It could be OK as-is, but hits me a little odd that your present condition photo shows the "star" pattern not being bilaterally symmetric wrt the rotor --not mathematically wrong to do this (as long as the fixed side of the pick-up is in the correct corresponding place), but, if I was the Designer, I would've gone symmetric on that just to keep it easy to remember...and the same thing might apply to the fixed pick-up side of things (although that pattern looks asymmetric in your photo and would only go one way...just a thought...
     
  8. Sledge4.2

    Sledge4.2 F1 Rookie

    Oct 19, 2007
    4,789
    Marin
    Full Name:
    Geno
    #33 Sledge4.2, Dec 28, 2013
    Last edited by a moderator: Sep 7, 2017
    There is no way to adjust the pickup that i can see.

    the 8 point star is keyed to the distributor shaft (only one way)

    the pickup sensor bracket is welded on the plate, and that plate gets screwed to the body with no adjustment possible.

    The secondary bottom plate screws one way onto the top plate. The inner winding only goes in one way, in a fixed position.

    The mechanic advance spring clip preventing the spring from popping off is broken, and when i took it apart one of the springs was off, but not sure if it came off as a result of me taking the dist apart or if it was already off. The advance seems to be stiffer with it on, but i recall the distributor advancing properly if not a bit early.....
    Image Unavailable, Please Login
    Image Unavailable, Please Login
    Image Unavailable, Please Login
     
  9. Sledge4.2

    Sledge4.2 F1 Rookie

    Oct 19, 2007
    4,789
    Marin
    Full Name:
    Geno
    The two pickup wires were reversed coming out of the distributor to the MSD box (mislabeled, so plugged in wrong). If you get the polarity mixed, it can cause up to 10 degrees of advance at the distributor, which is what was happening. Swapped the connectors, and it times perfectly.
     
  10. 2NA

    2NA F1 World Champ
    Consultant Owner Professional Ferrari Technician

    Dec 29, 2006
    18,221
    Twin Cities
    Full Name:
    Tim Keseluk
    Good to hear. It really is frequently the easy stuff.
     
  11. Sledge4.2

    Sledge4.2 F1 Rookie

    Oct 19, 2007
    4,789
    Marin
    Full Name:
    Geno
    its amazing how well that little car runs with the right advance....

    :)
     

Share This Page