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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?
     
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  3. Dale

    Dale F1 Veteran

    Oct 7, 2003
    5,211
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    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.
     
  4. tbakowsky

    tbakowsky F1 World Champ
    Professional Ferrari Technician Consultant

    Sep 18, 2002
    16,925
    The Cold North
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    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.
     
  5. Dale

    Dale F1 Veteran

    Oct 7, 2003
    5,211
    uk
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    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.
     
  6. ferrarifixer

    ferrarifixer F1 Veteran
    BANNED

    Jul 22, 2003
    8,520
    Melbourne
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    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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  8. Piston.Broke

    Piston.Broke Karting

    Mar 5, 2009
    50
    Australia
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    Rick
    Hi all.
    Can anyone post a picture of the cam timing marks on a 400i. Also can anyone confirm that the cam timing marks should be aligned when No.1 cylinder is at TDC for both banks?
    Thanks.
    Piston.Broke
     
  9. Ferrari Tech

    Ferrari Tech Formula Junior

    Mar 5, 2010
    839
    Georgia
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    Wade Williams
    The marks are all set off of the number one cylinder at TDC. I do not have a picture of the cam marks on a 400i.
     
  10. Piston.Broke

    Piston.Broke Karting

    Mar 5, 2009
    50
    Australia
    Full Name:
    Rick
    Thanks Ferrari Tech,
    I have the cam chain covers off with No.1 at TDC but can only see a scribe mark on one cam.
    Cheers!
    Piston.Broke
     
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  12. Piston.Broke

    Piston.Broke Karting

    Mar 5, 2009
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    Australia
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    Rick
    Great raemin.
    Very helpful - is the timing mark a dot or a scribed line?
    Cheers!
    Piston.Broke.
     
  13. raemin

    raemin Formula 3

    Jan 16, 2007
    1,216
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    R. Emin
    A scribed line. There was a bit of paint on top of the line on my camshaft, not stock obviously, but easier to capture with the camera.

    You can have a bit more advance on the inlet camshaft: on the 412, they added 4° compared to the 400i. So if your camshaft is slightly advanced, no need to worry.
     
  14. Piston.Broke

    Piston.Broke Karting

    Mar 5, 2009
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    Rick
    Great info!
    Thanks again for your assistance.
    (Unfortunately, I cant find the scribed line on one of the cams).
    I'll see what I can do to check the timing/adjustment.

    Cheers!

    Piston.Broke
     
  15. Steve Magnusson

    Steve Magnusson Two Time F1 World Champ
    Lifetime Rossa

    Jan 11, 2001
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    Steve Magnusson
    You have to be with No. 1 at TDC and also No. 1 at the end of its compression stroke (i.e., the location where No. 1 is ready to fire with both valves fully closed). Are you sure that you are not off by one crankshaft revolution?
     
  16. Piston.Broke

    Piston.Broke Karting

    Mar 5, 2009
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    Australia
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    Rick
    Thanks Steve,
    Good advice - but yes, I made sure that No.1 was on compression and initially set it up using the PM 1 and 6 marking on the flex plate. This seemed to be fairly accurate but I am happy for any further advice on this. (I dont have a dial gauge and was just going to initially check if the cam timing marks were 'in the ballpark').
    It is possible that the cam chain may have stretched somewhat, hence my desire to check the actual timing marks whilst at TDC.

    Thanks.

    Piston.Broke
     
  17. Piston.Broke

    Piston.Broke Karting

    Mar 5, 2009
    50
    Australia
    Full Name:
    Rick
    #15 Piston.Broke, Apr 24, 2021
    Last edited: Apr 24, 2021
    OK.
    An update on the cam timing and ignition check on the 400i.

    I removed the distributor to check that the fly weights (for high rev ignition advance) were working properly. The distributor was easy to remove and dissassemble, so that you can check and lubricate the centrifigal fly weights in the base of the distributor. Once this was done I set the ignition timing (staticly) using the 8 deg advance mark on the flex plate. (This is done from under the car, so it helps to have a car lift available).
    Note:
    Be advised that even though the 400i uses a single distributor and coil for ignition, it still has timing marks for A bank and B bank on the flexplate
    (My car is an Auto). This is an issue as when I first set up the distributor with the lower peg of the rotor set to No.1 spark plug (there is an index mark for this on the distributor body) I thought (incorrectly) that the timing was all set to go. But no, she wouldnt fire. Back under the car again to check the timing marks and guess what - yes, there are two sets of ignition timing marks! This must be a hang over from the earlier cars which utilised 2 distributors and 2 coils, both with slightly different timing requirements.
    So, for a 400i make sure you use the timing mark AF 8 deg marked as A bank.
    It was relatively easy to simply set it on the correct mark at AF 8 deg and then pull the distributor and re-set it in the drive splines so the rotor was once again pointing at No.1 (use the ref mark on the distributor body for this).
    Once this was done, I removed both cam chain covers to check the camshaft timing.
    Again, this is not difficult to do, provided you take your time. On the RHS cam chain cover you do have to remove the vacuum pump and the Oil filler. You will also have to release the Oil dipstick to allow the RHS cover to come off. You will also have to remove bith fuel injection warm up regulators but these can be moved to the side whilst keeping the fuel lines undisturbed.
    At this point, (as I dont have a dial gauge) I just wanted to check that the cam timing marks looked OK with No.1 cylinder at Top Dead Center (TDC). A number of owners have reported that the relatively long chain drive to the cams can stretch over time and disturb the cam timing. It is very important when doing this to make sure that No. 1 Cylinder is on its compression stroke and that it is set at TDC. As I was working on my own, I simply set up a compression tester in No.1 Cylinder and used the starter to turn the car over until I got the start of compression pressure indictaing in No.1 Cylinder. After this I got under the car again and set the timing marks on the flex plate (set at the factory) to PM 1 6. This indicates TDC for both cylinders 1 and 6. (I think in Italian the PM represents 'Punto Morte' meaning 'Dead Point' - same as TDC).
    Once this was done, it was back up top to view the cam timing marks and see how far out they might be. Well, amazingly, they all apeared to be within 1 or 2 deg of the factory timing mark except for Cam No.3 which (ofcourse) has absolutely no timing marks on it at all !!
    As all the other cams look good and seem to be timed correctly, I will leave well enough alone and assume that No.3 cam is set up properly. (I assume that No.3 cam may have been replaced prior to my ownership and that it wasnt marked up after installation).
    In a couple of days, she goes all back together and hopefully all will be well.
    I hope this info has been helpful, as although I have had my 400i for around 15 years - I havent really delved into the mechanicals very much in the past.
    Cheers!
    Piston.Broke
     

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