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Timing Belt Change Question

Discussion in '308/328' started by twright, Feb 27, 2010.

  1. twright

    twright Karting

    May 15, 2005
    225
    Indianapolis USA
    I have just changed the timing belts on my 308GTBi.

    Do the front cams have timing marks on them like the rear ones do? Is there a way to verify that I have the front belts on at the correct location?

    It is easy to verify that the rear cam is timed correctly on the rear bank. Just look through the oil filler hole at TDC. Is there a similar way to do it on the front bank? Or can it be be verified by removing the front valve cover?

    I just want to check everything before I put it all back together.
     
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  3. Hans

    Hans F1 Veteran

    Feb 17, 2006
    7,723
    Hilversum, Netherlands
    Full Name:
    Hans Teijgeler
    Remove a plug and put a long screwdriver in?? Easy to spot TDC that way...
     
  4. twright

    twright Karting

    May 15, 2005
    225
    Indianapolis USA
    Yes, but how do you know if the cams are in the right location at TDC?
     
  5. yelcab

    yelcab F1 World Champ
    Consultant

    Nov 29, 2001
    10,668
    San Carlos, CA
    Full Name:
    Mitchell Le
    If you remove the valve cover, you can see the marks like the 1-4 bank. If you really worry about it, then degreeing the cam will get you there. But, it is almost a concensus that the 308x cams are forgiving enough that the marks will get you there.
     
  6. gonzo350

    gonzo350 Karting

    Apr 3, 2004
    207
    Lafayette Indiana
    Full Name:
    Myles
    #5 gonzo350, Feb 27, 2010
    Last edited by a moderator: Sep 7, 2017
    On my QV there is a metal pointer on the fiberglass backer that attaches to the pulley covers (this is on both the front and rear banks) that points to a mark on the cam. These marks are in the same alignment as the marks on your cam & cam cap, and thus provide and external way to verify cam timing w/o removing the valve covers. NOTE: These are NOT as accuriate as looking at the cam itself due to the ability of the fiberglass to move around....DO NOT use it as a sole reference when doing your cams....this is just a way to double check things.
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  8. CliffBeer

    CliffBeer Formula 3

    Apr 3, 2005
    2,192
    Seattle, Washington
    Full Name:
    Cliff
    Ditto the above - if you're at TDC on the flywheel and you pull the cam covers and the marks are on the money on the cams/caps then you're in good shape. Certainly, degreeing the cams is a more precise method no doubt, but you shouldn't have to degree the cams every time you change the belts.....
     
  9. twright

    twright Karting

    May 15, 2005
    225
    Indianapolis USA
    Thanks for all the help. I pulled the front valve cover (not a real pleasant task) and all is good.

    I just have to put the rest of it back together now.
     
  10. docmirror

    docmirror Formula Junior

    May 6, 2004
    772
    Ft Worth TX
    My experience was different. I've only done three belt jobs but I checked the degree on all of them. They were all out of spec on the front cams. On two cars, both cams were > 2 deg out of spec, and on the last car, the exhaust was > 3 deg wrong, and the rear exhaust was also off.

    For a DIY guy, knowing what I know now I won't do a belt job without valve lash and degree check. YMMV
     

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