how far can the factory cam marks be off? | FerrariChat
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how far can the factory cam marks be off?

Discussion in 'Technical Q&A' started by jackgt, Aug 9, 2015.

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  1. jackgt

    jackgt Formula Junior

    Jan 27, 2015
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    #1 jackgt, Aug 9, 2015
    Last edited: Aug 9, 2015
    I am still working on my 360 engine. FINALLY I understand how Ferrari gets the numbers they do for checking timing. And also finally saw the +- tolerances in small numbers after the specs. I have a question. How far can the factory marks be off? My ex cam is only rising .1mm after 9 deg BTDC and I have checked it 3 times--Also, hang with me, I am almost done with this and hopefully some others have learned from all the, sometimes dumb questions!!!
     
  2. 360+Volt=Prius

    360+Volt=Prius Formula 3
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    #2 360+Volt=Prius, Aug 9, 2015
    Jack, I'm not a pro but something sounds off. Some of the pros say they can be pretty badly off. I know both of my exhaust cams were off (by how much I don't recall). So you may need to adjust the exhaust cams. Before you do
    -are you SURE TDC is stillcorrect. Re check it.
    -are you sure the dial gauge is mounted properly and exactly perpendicular to the lifter.
    -are you sure you are turning the crank enough.
     
  3. 360+Volt=Prius

    360+Volt=Prius Formula 3
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    #3 360+Volt=Prius, Aug 9, 2015
    Wait, you just changed the variators so you must have taken the cam pulleys off, so how did u put them back on? Even if u marked them it really won't be possible to get it back spot on without adjustment. That assumes the new variators pulley bolt threads were to be in exactly the same place, which I highly doubt is possible. The more I think about this the more it seems ex cans need adjusting. You can maybe pm or ask for one of the pros to chime in.
     
  4. jackgt

    jackgt Formula Junior

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    #4 jackgt, Aug 9, 2015
    well I hope one of the pros or someone that has had this situation chimes in. I did change the variators, but the marks on the cams at each end line up perfectly on all 4 cams. I did recheck TDC and ALL of the factory marks still line up. the first intake was 1.70, real close. .5mm seems like a bit far off. I turned the crank so the ex valve opened and was closing, zeroed the dial indicator at 9 deg befpre TDC and it only went to 0.1mm when turning the crank clockwise 1/4 turn.
     
  5. 360+Volt=Prius

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    #5 360+Volt=Prius, Aug 9, 2015
    Ok, but the cam pulleys were taken off right?
     
  6. jackgt

    jackgt Formula Junior

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    #6 jackgt, Aug 9, 2015
    yes I did, but all of the cam marks from the factory line up. I marked the ex cams in relation to the pulleys before I took them apart. did as much marking as I could through the whole process. a paint pen is your friend on this job!!!!
     
  7. 360+Volt=Prius

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    #7 360+Volt=Prius, Aug 9, 2015
    sounds like they need to be degreed, that's what I would do. I know cause I painstakingly marked mine but they all4 needed to be adjusted when I removed the pulleys to change the 4 seals.
     
  8. 360+Volt=Prius

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    #8 360+Volt=Prius, Aug 9, 2015
    And don't forget you are bolting the old pulley to the new variators and the marks even if previously accurate may no longer be relevant.
     
  9. jackgt

    jackgt Formula Junior

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    #9 jackgt, Aug 9, 2015
    the intakes were easy, I changed the seals also. I just put them back where the same washer marks were. the first one was perfect. I just want to throw out there how far my ex cam is and to make sure I am checking it right.
     
  10. 360+Volt=Prius

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    #10 360+Volt=Prius, Aug 9, 2015
    Sounds like you are!
     
  11. jackgt

    jackgt Formula Junior

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    #11 jackgt, Aug 11, 2015
    Well, went to a mechanic that knows his stuff, since nobody out there has had much experience on how far the marks have been off. He said that he also has not seen too many that were off of factory marks. I will check the other bank just for the hell of it and leave the cams on the factory marks and call it good.
     
  12. 360+Volt=Prius

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    #12 360+Volt=Prius, Aug 11, 2015
    Jack, I think that may be a mistake. Like I have said before, You have removed the variators.

    Let me ask u this, when u are at TDC where are the aft scribe marks now? Are they spot on?

    I would PM rustybits and rifledriver to comment on this and your prior degree cam thread..

    Lastly, rifledriver has posted that he has seen 360 factory marks off by larger margins then one would expect.
     
  13. Ferrari Tech

    Ferrari Tech Formula 3

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    #13 Ferrari Tech, Aug 12, 2015
    As a Master tech, every major service gets a re-set with a degree wheel and dial indicator.
    If you had the pulley off of a 360, use the factory method and get it in spec. If it is off, adjust it. The cams are small and you probably won't notice the marks move much with the adjustment you need.

    Oh, to answer the original question, I have seen cam marks that are not close at all when properly timed. It happens.
     
  14. jackgt

    jackgt Formula Junior

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    #14 jackgt, Aug 12, 2015
    Thanks Wade. I hear so much back and forth on these engines that I wanted to hear from someone that has done a bunch of them in the past. this is a project car and a lot different that what I have done before. Not hard or complicated, just different the way things are done!!!!
     

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