Checking cam timing on Mondial T - confusion... | FerrariChat
Buy

Checking cam timing on Mondial T - confusion...

Discussion in 'Technical Q&A' started by nicce12, Aug 16, 2015.

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

  1. nicce12

    nicce12 Karting

    May 22, 2013
    76
    Stockholm, Sweden
    Full Name:
    Niclas Olovsson
    #1 nicce12, Aug 16, 2015
    Last edited by a moderator: Sep 7, 2017
    Hi!

    I am in the process of doing an engine out service on my Mondial T (1990) and I decided to check the cam timing before I re-install the engine, I have looked at the threads by fatbillyboy http://www.ferrarichat.com/forum/technical-q-sponsored-algar-ferrari/148917-degreeing-cams.html and the summary by adsphelan http://www.ferrarichat.com/forum/technical-q-sponsored-algar-ferrari/356085-348-cam-timing-instructions.html.

    WSM lists Not Catalyzed as
    Intake open @14* Before Top End Center (TDC), closed @ 53*After Bottom End Center (BDC)
    Exhaust opens @ 53* Before Bottom End Center closed @ 10*After Top End Center (See Picture)
    and WSM lists Catalyzed as
    Intake open @12* Before Top End Center, closed @ 56*After Bottom End Center
    Exhaust opens @ 54* Before Bottom End Center closed @ 10*After Top End Center (See Picture)

    I started with determining TDC and the notches on the cams aligns pretty good with TDC, picture of typical example.

    Then I measured Intake, and it seem to be reasonable aligned with the catalyst setting for 348 (I have cats on my Mondial):
    Intake open 12,5 Before Top End Center, intake close 57 After Bottom End Center (see pictures)
    Image Unavailable, Please Login
    Image Unavailable, Please Login
    Image Unavailable, Please Login
     
  2. nicce12

    nicce12 Karting

    May 22, 2013
    76
    Stockholm, Sweden
    Full Name:
    Niclas Olovsson
    #2 nicce12, Aug 16, 2015
    Last edited by a moderator: Sep 7, 2017
    Continued:

    The troubles comes when I measure the exhaust:

    I get a opening at 57 before Bottom End Center, with is off by 3-4 degrees (I think I read somewhere that a cog is 2,4 degrees) - but when I measure closed I get 52 After Top End Center (see Picture) which is way off from the expected 10 After Top End Center - and now I am utterly confused since I would have expected that I would be off the same amount both on opening and closing - am I miss-thinking how it works or could the clutz that worked on it before have mounted the wrong cam on the exhaust side???


    I have re-measured the exhaust several times from scratch, this evening I fabricated a better mount for my dial clock but I still get the same results. ...the engine seemed to be running a bit fat on this bank (high cat temp on the right and slightly high on emissions test) and was powerless when I was driving it, but since the cam belt age was unknown I did not push it in anyway and initiated the engine out service.

    Cheers, Niclas
    Image Unavailable, Please Login
    Image Unavailable, Please Login
     
  3. Ferrari Tech

    Ferrari Tech Formula 3

    Mar 5, 2010
    1,217
    Georgia
    Full Name:
    Wade Williams
    #3 Ferrari Tech, Aug 17, 2015
    I was taught that the most important numbers to use on Ferrari 4 cam engines is: Intake opening, get that right, and exhaust closing, get that right.
    I have measured cams before and they are not always dead on with open/close numbers in the books. You can't change how the cam is made, so, intake opening and exhaust closing being spot on will give great performance.
     
  4. ferrarioldman

    ferrarioldman Formula 3
    Professional Ferrari Technician Silver Subscribed

    Jun 19, 2002
    1,033
    Summerfield, NC
    Full Name:
    Tom Jones
    #4 ferrarioldman, Aug 23, 2015
    +1
     
  5. ernie

    ernie Two Time F1 World Champ
    Lifetime Rossa Owner

    Nov 19, 2001
    22,614
    The Brickyard
    Full Name:
    The Bad Guy
    #5 ernie, Aug 23, 2015
    Last edited: Aug 23, 2015
    Did you by accident swap the exhaust cams? Maybe you have the exhaust cams on the wrong sides?

    Also did you find top dead center (tdc) on #1, put the 1/4 intake and exhaust cams on the marks? Then find tdc on #5 and put the 5/8 intake and exhaust cams on the marks? You need to find tdc on both sides independently and then put the corespondent cams on the marks after you have found tdc. THEN go back and verify the timing. At least that's how I would do it.
     
  6. Ferrari Tech

    Ferrari Tech Formula 3

    Mar 5, 2010
    1,217
    Georgia
    Full Name:
    Wade Williams
    #6 Ferrari Tech, Aug 24, 2015
    If you are timing by the notch marks on the cams, you have to be on TDC of the #1 cylinder and all four cams line up at the same time. Do not switch to #5 for that bank of cams.
    When checking timing you will change TDC from #1 to #5.
     
  7. ernie

    ernie Two Time F1 World Champ
    Lifetime Rossa Owner

    Nov 19, 2001
    22,614
    The Brickyard
    Full Name:
    The Bad Guy
    #7 ernie, Aug 24, 2015
    Well son of a gun, I have it mixed up. Thanks for the correction.
     
  8. Mark 328

    Mark 328 Formula Junior

    Nov 6, 2003
    510
    Orange, Ca
    Full Name:
    Mark Foley
    #8 Mark 328, Aug 25, 2015
    I have not done that for a while, but you may want to check your before BDC and After BDC or could you have the numbers for the wrong bank? I thought my printable degree wheel had 0 at TDC and BDC like this one. I think you are probably too far off to be looking at cam wear. Also, I thought I did something to set TDC on both banks, or is 1 & 5 180 Deg apart? The 328 Technical Specifications manual goes over that pretty well.
    https://www.google.com/search?q=printable+degree+wheel&sa=X&hl=en&biw=1280&bih=829&site=webhp&tbm=isch&tbo=u&source=univ&ved=0CCwQ7AlqFQoTCLrHy9atxccCFZcziAodbWkK1g#imgrc=oCEcdQRz_3hGXM%3A
     
  9. Mark 328

    Mark 328 Formula Junior

    Nov 6, 2003
    510
    Orange, Ca
    Full Name:
    Mark Foley
    #9 Mark 328, Aug 25, 2015
    Hi,
    Looking again at your valve timing question, I think you need to have TDC for bank 1-4 then for 5-8. I would look at:
    GT4 Service Manual (basis for the V-8 Ferraris)
    328 Tech Specs
    328 Workshop Manual
    These are all available on-line here Private Ferrari Document Collection
    Also I liked this degree wheel printed in 11 x 17". This one has 0 at TDC and BDC
    I half wrote a Cam Belt change for a 328 (adapted from this one Timing Belt for a carbed 308) if you want email me back and I'll send it to you in draft from home.
     
  10. nicce12

    nicce12 Karting

    May 22, 2013
    76
    Stockholm, Sweden
    Full Name:
    Niclas Olovsson
    #10 nicce12, Sep 30, 2015
    Last edited by a moderator: Sep 7, 2017
    Hi again!

    Sorry for the lack of updates, life stuff came in-between the last weeks but now I took a fresh start with a better degree wheel with 0 at both TDC and BDC as Mark suggested, I fashioned a proper piston stop and replaced the steel wire with a magnetic line laser. I started with the first bank and now I got the following values:
    Intake opening 15deg bef TDC, Intake closing 56 deg after BDC
    Exhaust opening 56 deg bef BDC, Exhaust closing 1 deg bef TDC
    The exhaust seem off but at least the range of the values make sense, I must had failed in my conversion from the 360 degree wheel or my measurements... :$
    Now I just need to adjust the timing for the exhaust (intake will have to do) - I will go with Wades recommendation and aim for a correct closing at 10 degree after TDC.

    Thanks for all the help!
    Image Unavailable, Please Login
    Image Unavailable, Please Login
    Image Unavailable, Please Login
    Image Unavailable, Please Login
     
  11. Rifledriver

    Rifledriver Three Time F1 World Champ

    Apr 29, 2004
    37,105
    Cowboy Capitol of the World
    Full Name:
    Brian Crall
    #11 Rifledriver, Sep 30, 2015
    In one of your pictures the degree wheel looks very off center. That will cause readings to be very inaccurate. It needs to be perfectly centered. It is every bit as important for the dial indicator spindle to be exactly parallel to the valve stem being measured.


    Like Wade said, the In. Open and Ex. Close are the most important events.
     

Share This Page