Cam Timing Dilemma | FerrariChat

Cam Timing Dilemma

Discussion in '360/430' started by dennis_maine, Aug 23, 2018.

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  1. dennis_maine

    dennis_maine Karting

    Sep 11, 2007
    196
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    Full Name:
    Dennis Haines
    The car is a 1999 360 Modena, 18,000 miles. I have owned it over 2 years, and it always ran strong, pulling like a race horse in all 6 gears.
    I have an invoice from a well-regarded Ferrari dealership that states that the variators and the left hydraulic tensioner, along with a major service, were done in 2005 at 8,000 miles, under warranty.
    I also know that the car was in storage for most or the time since then, so I knew the timing belts were on borrowed time, to say the least. So, I am in the process of doing a major service. What I found has me stumped. At TDC for number 1 cylinder (front-most on the left bank), the timing marks on all 4 cams are off by, I would guess, 30 degrees. If this is true, how did it run so well?
    Could someone look at the attached photos and comment? There is a photo of the timing marks with #1 at TDC, or within a very few degrees. The other photo is of the left cylinder head, looking toward the front. The intake cam is above, or to the right of, the spark plug hole.
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  2. mike32

    mike32 F1 Veteran

    May 13, 2016
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    Isle of man- uk
    Are you sure you are turning the engine in the correct direction
     
  3. Mickster

    Mickster Formula Junior

    Oct 24, 2015
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    Mikael Andersson
    Well - Like a girl once told me: You’re in the wrong hole...

    Nr1 cyl is in the right bank closest to the passenger (if you drive on the right side of the road ;)).

    After I did the timing on mine I did a comp test (wet cylinders). Picture is showing the results and cylinder numbers.

    Oh - How it went with the girl? I told her: I’m sure it’s correct and kept on planting potatoes.
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  4. timwu12

    timwu12 Formula Junior
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    Oct 31, 2014
    919
    TX
    yup, your #1 cylinder is not on the left side, it's on the right side (passenger side for LHD cars)
     
  5. dennis_maine

    dennis_maine Karting

    Sep 11, 2007
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    Dennis Haines
    Wow-that's embarrassing. But its better than the timing being that far out! Thanks everyone!
     
  6. ItalGerBrit

    ItalGerBrit Formula Junior

    Mar 15, 2016
    804
    S La
    "Well - Like a girl once told me: You’re in the wrong hole..."
    Better in wrong hole than in no hole at all!
     
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  7. dennis_maine

    dennis_maine Karting

    Sep 11, 2007
    196
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    Full Name:
    Dennis Haines
    Well, I replaced the right bank hydraulic tensioner. I replaced the belts and set the tension by the frequency method. With the right bank tension set within specs, the gap at the top of the tensioner is below spec (about 1.2 mm). The left tensioner gap is zero. So, some more questions:
    1. What can be done if I cannot get both the gap and the frequency in spec at the same time? Which one governs?
    2. Since the left tensioner gap is zero, should I replace the tensioner on that side too?
    3. OK, this isn't a question. I owned a Mondial; for 11 years. On that car, you changed the belts, rotated the crank two times, and locked down the spring-loaded tensioner. All done. Also, it had clear TDC marks on the flywheel. Just saying.
     
  8. FlyingHaggisRacing

    FlyingHaggisRacing Formula 3

    Jul 2, 2013
    1,368
    To me it's a bit 'tai-chi'...
    if the tensioner and belt are all good, both the gap and the frequency will be within spec -
    It's not one or the other, but largely controlled by the tensioner pulley .
    I found it took 2 turns for things to settle after each adjustment and in the end even the pin would slide in and out.

    If the other tensioner is at zero - then it's buggered or you did something wrong.

    :confused:
    I'll admit in public to my secret mistake - this will make the experts laugh.
    The 1st time i did it, i rotated the belt tensioner pulley in the wrong direction (didn't look at the photo of how it was before i took the belt off).
    All seemed fine, but the gap would not come right even though the freq was spot on.
    Took hours for me to figure it out. I feel much better now for sharing that dark secret.
     
  9. Ghostdiver

    Ghostdiver Formula 3
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    Mar 18, 2005
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    Wally Hollar
    #9 Ghostdiver, Sep 4, 2018
    Last edited: Sep 4, 2018
    1. I would say gap overrides frequency for the simple matter that if the belts are too tight and they cause the tensioner pulley arm to bottom out on the body of the tensioner assy. you run the risk of jumping time. HOWEVER....notice the caps....both will come into align, as I had both L&R gapped and tensioned correctly when I sent it out...I was just off a few teeth (as long as we are telling on ourselves!). This only happened after I replaced both tensioners with OEM NIB parts and a lot of contorted positions and words. Be sure to use the proper tool or a suitable one to both hold the tensioner bolt and torque it at the same time.
    2. Set the tension on the left side the same way you did on the right, If the tensioner bottoms out after sitting for several hours, I'd say change the tensioner assy.
    3. DOHC Ferrari's are a special beast and are the most finnicky engines I've dealt with and I've played with some real winners before!
     
  10. Ghostdiver

    Ghostdiver Formula 3
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    Mar 18, 2005
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    If you've never heard the term tolerance stacking....this is what you are dealing with. Both the tensioner gap and the frequency have a range. Get either one too high, too low within that range and it could and will throw off the overall...It takes time and a whole lot of patience....beer helps but only if your not prone to throwing tools....
     
  11. dennis_maine

    dennis_maine Karting

    Sep 11, 2007
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    Dennis Haines
    Flying Haggis Racing: Thanks for admitting to a mistake. Makes us mere mortals feel better. Both idler pulleys are rotated CW to increase tension, correct?
    Ghostdiver: Thanks for all of your help. I am familiar with tolerance stacking. I'm an old guy with plenty of time, so I'll keep playing until I get it right.Or what I think is right.
     
  12. 24000rpm

    24000rpm F1 Rookie

    if you rotate the bearing it in the wrong direction, can it still "hold" and run correctly? , assuming the frequency is right.

     
  13. FlyingHaggisRacing

    FlyingHaggisRacing Formula 3

    Jul 2, 2013
    1,368
    When i did this, it seemed to hold just fine, but the tensioner gap wouldn't fall in spec.
    It was close but i could not get the pin hole to align as everyone talks about.

    As to what would happen if the engine ran that way - who can tell, but it wouldn't surprise me if it would run perfectly fine.
     
  14. 24000rpm

    24000rpm F1 Rookie

    i might got mine rong. ah!!! i might have to do it again!

    my gap is around 4mm, and the frequency is right! new tensioner, new tensioner bearing, new everything


     
  15. 24000rpm

    24000rpm F1 Rookie

    so what's the correct direction then?

    so
     
  16. Ghostdiver

    Ghostdiver Formula 3
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    Dennis, what are you using to do this....the WSM alone or do you have the edited version Black360 wrote up some time ago?
     
  17. dennis_maine

    dennis_maine Karting

    Sep 11, 2007
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    Dennis Haines
    I am using every single word I can find on the subject! WSM, Aldous Voice, this site, other Ferrari sites.
     
  18. Ghostdiver

    Ghostdiver Formula 3
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    Mar 18, 2005
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    Wally Hollar
  19. dennis_maine

    dennis_maine Karting

    Sep 11, 2007
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    Dennis Haines
    Thank you. I was just about to post that I couldn't find Black360's writeup.
     
  20. FlyingHaggisRacing

    FlyingHaggisRacing Formula 3

    Jul 2, 2013
    1,368
    Rotation
    Not 100% sure now - but CW seems to be what i remember.
     
  21. dennis_maine

    dennis_maine Karting

    Sep 11, 2007
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    Dennis Haines
    Well, now I have another question (after taking time off to go to Watkins Glen for the SVRA weekend). For bolt torque setting, my WSM says "Tightening of belt tensioner bracket", and "Tightening of belt tensioner to bracket" both "M10 x 1.25, torque 49 Nm. That's what I did, using new bolts. Then, I thought about it. Those bolts aren't M10, they're M8. The torque should be half that. So, are the bolts going to snap in service? Also, I can't find any data on the idler pulley bolts. Anyone know the torque for those?
     
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  22. andytr

    andytr Rookie

    Dec 13, 2016
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    Andy Murray
  23. dennis_maine

    dennis_maine Karting

    Sep 11, 2007
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    Dennis Haines
    Thank you. It is a good article but does not mention bolt torque values.
     
  24. Ghostdiver

    Ghostdiver Formula 3
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    Mar 18, 2005
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    Wally Hollar
  25. dennis_maine

    dennis_maine Karting

    Sep 11, 2007
    196
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    Full Name:
    Dennis Haines
    Thank you. My WSM , Section A 3.04, says Generator-Water Pump: 100 Hz; AC Compressor: 145 Hz; Steering Pump: 100 Hz. It's a wonder these cars ever get fixed right. Not only that, my trusty Craftsman torque wrench died Saturday, and the local store won't have a replacement until Monday. If it ain't one thing,........
     

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