belt change gone south | FerrariChat

belt change gone south

Discussion in '308/328' started by race27, Jun 5, 2017.

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  1. race27

    race27 Rookie

    Nov 11, 2003
    17
    between robzworkz and birdman getting the belts nd tensioners changed over was going pretty well until it came to tensioning. Decided to use the verell technique with the cams locked. While rotating the crank to get the correct tension the lock on at least one bank of cams failed so the cams jumped timing. realize i now have to remove the valve covers to reset the cams but cannot seem to find any info on how to reset the cam timing. Please help!!! Thanks
     
  2. spicedriver

    spicedriver F1 Rookie

    Feb 1, 2011
    3,859
    That's why you should mark the pulleys with whiteout, or touch up paint, so you don't have to pull the cam covers to see where they should be set.

    The camshafts have a little "dash" timing mark on them. You should be able to see one through the oil fill cap.

    If a camshaft moves a little from spring pressure, that is not enough to damage anything. Just make sure everything is lined up before you turn the engine. You can easily bend the valves just by turning the engine by hand.
     
  3. Martin308GTB

    Martin308GTB F1 Rookie

    Jan 22, 2003
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    Martin N.
    #3 Martin308GTB, Jun 5, 2017
    Last edited by a moderator: Sep 7, 2017
    I don't understand completely. You had the cams locked while trying to turn the crankshaft?
    What car? Some camshafts have a mark on the pulley flange and there's a Ferrari tool for checking timing without taking off the camshaft covers. Should be possible to fabricate oneself.

    Best
    Martin
    Image Unavailable, Please Login
     
  4. 4redude

    4redude Formula Junior

    Jan 13, 2005
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    Fungus Corner
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    Brian Keegan
    See Service Bulletin 10-3 dated 7-10-1980. It describes the tool and says that the external
    marks on the camshafts started with F106 USA engine # 00801.
     
  5. Rifledriver

    Rifledriver Three Time F1 World Champ

    Apr 29, 2004
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    That tool is for the 2 valve. His profile is empty so no knowing what car he has.
     
  6. race27

    race27 Rookie

    Nov 11, 2003
    17
    car is an 87 328. cam sprockets are marked. so what i am understanding is that if i remove the belts again, go to tdc, make sure the cam with the marks that line up in the oil hole are in line then move the other cams to the marks on the sprockets then i won't need to take off the valve covers to reset cam timing???
     
  7. 308 milano

    308 milano F1 Veteran

    Jan 15, 2007
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    ?? Yeah, what's up with that?
    If that seemed like a good idea then its clear you better call someone with experience to help you out. I would be less concerned with the minimal job of pulling those cam covers if necessary to make absolutely, positively sure things are correct... or you stand a very good chance of having an expensive week.
     
  8. Martin308GTB

    Martin308GTB F1 Rookie

    Jan 22, 2003
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    I agree 100%
    Here's disaster waiting to happen. Do not touch or try to turn anything. An experienced mechanic could now recover things depending on how much you are off from TDC and how much the timing is off.
    I just imagine being in the same situation. I would not only take off the covers. If things would be severely off I would also remove the camshafts before turning the crankshaft to TDC.

    Best
    Martin
     
  9. Glassman

    Glassman F1 World Champ
    Rossa Subscribed Silver Subscribed

    The idea is that with the cams locked you apply pressure on the crank with a breaker bar to take all slack out of the belt, then tighten the tensioner bearings. The concept is to not lean on the breaker bar. I have used this technique a few times. I now use the factory directions.
     
  10. spicedriver

    spicedriver F1 Rookie

    Feb 1, 2011
    3,859
    Understand that there is not clearance between the valves and pistons. So moving the camshafts, or crank independently of each other can result in bent valves with no compression.

    Also, the crank spins twice every time the cams spin once. So just because the crank was at TDC, doesn't mean the cams were, unless you checked for that timing mark before you started. They could be 180 degrees out.

    Find out where exactly the timing marks are first before you move anything.
     
  11. johnk...

    johnk... F1 World Champ
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    Jun 11, 2004
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    #11 johnk..., Jun 6, 2017
    Last edited: Jun 6, 2017
    I'll start by asking some necessary question.

    1) Were the timing marks lined up before you applied torque to the crank?

    2) You say the cams jumped timing. By that I presume the belt jumped a tooth or two, or more. Is that correct? Or did they just rotate with the crank and therefore move off marks?

    3) How far off TDC did you rotate the crank (not the cams)?

    Remember that when the crank is at TDC 2 cylinders are at the bottom of the stroke and two at the top. For those at the top one is at the top of the compression stroke and one is at the end of exhaust, start of intake. If the crank was only rotated 10 or 15 degrees, or less, there should be little concern of valves hitting pistons if the belt is removed, cams marks realigned and crank repositioned at TDC (rotating backwards, slowly). I would think that would be the case if you were just applying torque to tension the belts. But the above questions need to be answered before doing anything.

    Of course, caveat applies. Proceed at your own risk.

    Just don't rotate the engine significantly w/o the belt on and positioned correctly.
     
  12. mike996

    mike996 F1 Veteran

    Jun 14, 2008
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    I know this is too late but, from the description, I gather that although you locked the cams, you had NOT marked their position first with a paint line OR set the crank/cams at TDC. Therefore, you have no reference as to where the cams were in relation to the crank before removing the belt.

    Always mark the cam position - you can't "lose" the setting if the cams are marked, no matter what happens. If the cam shifts when the belt is removed - and that is quite common - you simply rotate the cam(s) back to the marked position when you install the new belt.

    Obviously, if you are so inclined, you can line the crank/cams at the provided TDC marks before removing the belt but I would mark the cams anyway because it's much easier to see the paint marks than the engine marks.

    Based on my understanding of your post (and I may be MIS-understanding) if you moved the crank after reinstalling the new belt and the cams moved with the crank, there is no problem - everything is still in the same alignment it was. Tensioning the crank and then having the "lock" slip does not change the alignment of the cams unless the belt was missing!

    FWIW, if the cam(s) are marked at whatever position they are in when the engine is stopped and before removing the belt/chain, that is all that is necessary to ensure it will be correct when the new belt/chain is installed. Obviously if you want to verify the correct timing, then before removing the old belt/chan, rotate the engine to align the appropriate marks and proceed from there.
     
  13. race27

    race27 Rookie

    Nov 11, 2003
    17
    Gents,
    Thanks for the help. Engine was at tdc and cams were marked prior to original belt removal. Belts were marked on cams as well. Crank was moved clockwise maybe 15* degrees only to take the slack out of the long side of the belt per verell method when the lock failed. i then moved the crank counterclockwise back to tdc and none of the marks were in line. At this point I do not want to guess if all is well I want to remove the cam covers and make sure. Can anyone tell me how to do this. Thank You
     
  14. yelcab

    yelcab F1 World Champ
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    Nov 29, 2001
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    Mitchell Le
    May I suggest that you fill in your profile with car and location so that one of us may be able to lend you a hand personally?
     
  15. Rifledriver

    Rifledriver Three Time F1 World Champ

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    That is an exceedingly poor procedure and it is unfortunate it ever got into the public domain but so goes the internet. If the crank moved 15 degrees to tension the belt the cams were destined to be out of time even if the belt had not slipped so this entire fiasco is a blessing in disguise.

    Stop where you are, take the valve covers off, take the cams out and do it right.


    There are some short cuts here but so much has already happened, far better to not consider them.
     
  16. JasonMiller

    JasonMiller F1 Rookie
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    Jul 16, 2004
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    exactly! Where are you located? Maybe someone can help.
     
  17. Martin308GTB

    Martin308GTB F1 Rookie

    Jan 22, 2003
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    #17 Martin308GTB, Jun 6, 2017
    Last edited: Jun 6, 2017
    Though this doesn't help I think it's a pity, that a procedure invented by some reputable FChat-tech-buddies went so severely wrong.
    But I also have to admit, that I always thought it is a risky procedure and I proceeded using the factory directions from the WSM.
    Regarding paint or whiteout marks. I agree, that it's mandatory whenever one takes off the belts with the camcovers installed.
    I even do it on my 2-valve car, where the cams -as opposed to the QV-engines- do not tend to move with the belt removed. So there's also no need for a clamping device. I only do without paint marks, when the covers are off anyway during a big service with valves, camshaft seals, cams off, etc.
    I never needed the marks so far, but better safe than sorry. And on my drysump car I wouldn't even have the chance to see the inner cam marks through the oil filler, since there's no such thing.
    (wouldn't help anyway on the forward bank)

    15 deg. to take out the slack? Did you already miss one belt tooth while fitting the belt? Though I believe this would make putting the belt onto the tensioner impossible. But who knows. I'm not familiar with the 328 engine. On the 2-valve cars it's tight putting the belt onto the tensioner. Even when all is correctly set. (tensioner fully released)
    No brute force needed, but tight.

    Best
    Martin
     
  18. MNExotics

    MNExotics F1 Rookie
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  19. Rifledriver

    Rifledriver Three Time F1 World Champ

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    I suspect that for whatever reason he had all the slack on the long portion of the belt after installation. That is why the 15 degrees. Who knows how it came to that. If it really happened that way the cams were going to be out of time at the end of the job.
     
  20. johnk...

    johnk... F1 World Champ
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    Jun 11, 2004
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    +1
     
  21. Dr Tommy Cosgrove

    Dr Tommy Cosgrove Three Time F1 World Champ
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    I have never changed a timing belt before but I don't understand why you would ever turn the cam once it is off.

    How is that ok to do under any circumstance, especially on an interference engine?
     
  22. Rifledriver

    Rifledriver Three Time F1 World Champ

    Apr 29, 2004
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    Its OK if you know where all the internal parts are. I don't hire people that cant look at a cam and not tell me where the piston is. That level of understanding is a minimum standard as far as I'm concerned.
     
  23. Blackandbluedino

    Apr 16, 2013
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    Newport News VA
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    Thomas Gonnella
    I don't have any real good solutions but I thought I would add this caveat... A few weeks ago I was at Radcliffe Motorcars for their annual Ferrari/All Italian Car Day and we had a great tech session with Tom Yang about the timing belts on the V-8s. What it boils down to is there isn't any correct way to change the belts without removing the cam covers and lining up all of the timing marks. Doing anything else is less than correct and can have mechanically catastrophic consequences.
     
  24. Martin308GTB

    Martin308GTB F1 Rookie

    Jan 22, 2003
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    Hmmm.... kind of very stringent view.

    Best
    Martin
     
  25. Dr Tommy Cosgrove

    Dr Tommy Cosgrove Three Time F1 World Champ
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    I guess with the engine on an engine stand too, right?
     

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