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400i valve timing

Discussion in 'Technical Q&A' started by timthetooth, Jun 6, 2004.

  1. timthetooth

    timthetooth Rookie

    Dec 18, 2003
    33
    The original marks on the camshaft caps on my car are present, but someone has made new marks on the tops of the caps. These new marks generally are very similar in position to the originals but not exactly. My question is are the original marks accurate, or is it possible a previous owner/mechanic has timed the cams differently? Is the stock timing best, or are there advantages to altering the timing?
     
  2. Dale

    Dale F1 Veteran

    Oct 7, 2003
    5,211
    uk
    Full Name:
    Dale Juan
    The origanal marks are a referance only,line them up and it works,its that simple,sorry i think not,manufactures dont put ajustable cam gears on for fun,
    dial gauge and engine out,its accurate,fun,and job satisfaction,you dont have to work on number 1 cylinder pick any on each bank,once the cam covers are off right down the firing order,the camshaft is the by far the most complex part of any 4 stroke engine,when a new profile of cam is fitted theres no need to put new marks anywhere,just dial them back in during cam belt service,new cam profiles should be kept with the cars service history so the tech as half a chance to set it back up well when new belts are fitted,

    cheers
    Dale.
     
  3. tbakowsky

    tbakowsky F1 World Champ
    Professional Ferrari Technician Consultant

    Sep 18, 2002
    15,098
    The Cold North
    Full Name:
    Tom

    400i are chain not belt. Set cam timing with a degree wheel and dial gauge for TDC. Basicly it'd set and forget on these cars. Just be sure your chain is not streached, and all guides and tensioners and in good working order. With all these parts in good shape you will have no problems settinf the timing and keeping there for a long time.
     
  4. Dale

    Dale F1 Veteran

    Oct 7, 2003
    5,211
    uk
    Full Name:
    Dale Juan
    Tom as you say chain is fit and forget,and how far as the valve timing moved when tappet service carried out,not far to be a big issue,good servicing never hurts any engine,its even better on chained,gear,cam drive systems to get the oil out at the right time,so my basic rules of setting the valve timing are not far away,

    cheers
    Dale.
     
  5. ferrarifixer

    ferrarifixer F1 Veteran
    BANNED

    Jul 22, 2003
    8,520
    Melbourne
    Full Name:
    Phil Hughes
    The single duplex chain of the 365/400 engines stretches an incredible amount. The timing on the cams can end up being miles retarded, and progressivley worse for each cam as it gets closer to the tensioner. I suspect your extra marks my be some precautionary ones done by a previous mechanic who was unsure of correct procedure.........

    If your chain adjuster has been wound all the way in already, you'll need a new chain to be installed. This is easily done by removing the camshafts and feeding the new chain in by connecting it to the old one, and turning the crank. Reset the sdjuster screw right out before you do this, and don't release the tensioner with the chain disconnected.

    I've dialled in several 365/400's, and in my experience, as with all Ferrrai's I've dialled, the marks can be trusted. They're never more than a degree or two off, and that's probably my human error in the test procedure.

    All the chain replacement and valve timing can be done with the engine in position. It only adds about 4 hours to a major service procedure.
     

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