Timing chain replacement | FerrariChat

Timing chain replacement

Discussion in '365 GT4 2+2/400/412' started by Godspeed!, Aug 31, 2008.

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  1. Godspeed!

    Godspeed! Karting

    Dec 1, 2006
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    Mandeville, Louisian
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    Dave Foley
    #1 Godspeed!, Aug 31, 2008
    Searched for a while, but did not come across any threads (might be something I am not doing correctly)which cover timing chain replacement, especially removing the front cover. From those who have done it, is it possible to do with the engine in place? Kinda in the study faze so any info pics etc will be greatly appreciated.

    Seems like the tensioning procedure is fairly straight forward, but would appreciate any tips. In the past, I did a couple Schnitzer twin cam F2 motors which are converted to manual tensioners similar to the 400's.

    Well, wife and daughter are off north, thank God the storm is so far going west a bit and not gaining the strength they expected!

    Godspeed!
    Dave
     
  2. Rifledriver

    Rifledriver Three Time F1 World Champ

    Apr 29, 2004
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    Brian Crall
    #2 Rifledriver, Aug 31, 2008
    The front cover will not come off in the car.

    The front cover is not removed to do a timing chain.

    Hook the new chain to the old one and roll it in.
     
  3. 2NA

    2NA F1 World Champ
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    Dec 29, 2006
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    Tim Keseluk
    #3 2NA, Sep 1, 2008
    Do you loosen the cam bearing caps so the valves are out of the way?
     
  4. Rifledriver

    Rifledriver Three Time F1 World Champ

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    #4 Rifledriver, Sep 1, 2008
    By the time you do that might as well just pull the cams.

    I've done it with and without the cams in the car.
     
  5. FERRARI-TECH

    FERRARI-TECH Formula 3

    Nov 9, 2006
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    #5 FERRARI-TECH, Sep 1, 2008
    I have done it both way's as Brian states, but just for my own comfort levels I pull the cams, and that is just me being anal, nothing wrong in either procedure
     
  6. Godspeed!

    Godspeed! Karting

    Dec 1, 2006
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    Dave Foley
    #6 Godspeed!, Sep 1, 2008
    Gee, this is good news. Figured this was possible, but wanted to wait till I heard from those who have done this before. Thinking this through in my mind, is this a two person job where tension is maintained on the feed out of the old chain as the new is rolled in? Should the tensioner be backed off? Any tips would be great. Being very cautious. Thanks soooooooo much for all the input.


    Having a nice cup of Java with my lab, watching the storm rool in. Winds 40-50 mph, pine trees waving to and fro...............
     
  7. wrxmike

    wrxmike Moderator
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    Mar 20, 2004
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    #7 wrxmike, Sep 1, 2008
     
  8. 2NA

    2NA F1 World Champ
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    #8 2NA, Sep 1, 2008
    It always helps to have another pair of hands/eyes. You'll probably want to remove the tensioner till the chain is in.

    Good Luck with the storm!
     
  9. judge4re

    judge4re F1 World Champ

    Apr 26, 2003
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    Dr. Dumb Ass
    #9 judge4re, Sep 1, 2008
    Check the condition of the tensioner while you're at it.
     
  10. SouthJersey400i

    SouthJersey400i Formula 3

    Mar 14, 2007
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    #10 SouthJersey400i, Sep 1, 2008
    Can the tensioner be changed through the same opening when changing the chain? Does the tensoiner all come out the side of the motor or out the top by the cams?

    Ken
     
  11. Rifledriver

    Rifledriver Three Time F1 World Champ

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    #11 Rifledriver, Sep 1, 2008
     
  12. SouthJersey400i

    SouthJersey400i Formula 3

    Mar 14, 2007
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    #12 SouthJersey400i, Sep 2, 2008
    Brian
    That makes the job sound a bit tougher. Do you turn the motor from the crank and keep the chain laid over the cams to keep everything in timing? If you do it with the cams out this will obviously be different. Why don't the valves hit the pistons in the latter case or do they not contact pistons in any configuration of misalignment?
    Ken
     
  13. Godspeed!

    Godspeed! Karting

    Dec 1, 2006
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    #13 Godspeed!, Sep 3, 2008
    Thanks for all the info. Some conflicting views. Yes, it would be hard fo rme to see how the chain would snake through with out turning the crank. But.......I have not done it. Originally I thought it possible to attach the new chain via the master link and with spk plugs out, slowly turn the crank with a ratchet.

    Observing the normal crank rotation, it appears that the lead in and out would take place at the drivers side exhaust cam. Is it possible to remove the actual tensioner rail through the tensioner piston/tensioner "access hatch" ? Seems like a large opening for just the tensioner piston bore. Then again the rail pivot pin would have to extract from the outside of the timing case in order to be able to remove it.

    My thoughts so far are from studying the parts diagrams, so any details from those who have done it are very much appreciated.

    Godspeed!
    Dave
     
  14. Rifledriver

    Rifledriver Three Time F1 World Champ

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    #14 Rifledriver, Sep 3, 2008
    Keep the chain engaged on the cams so they stay in time. The other choice is to pull the cams. The chain cannot simply just be fed through and pulled up the other side.
     
  15. timthetooth

    timthetooth Rookie

    Dec 18, 2003
    33
    #15 timthetooth, Oct 11, 2008
    It's extremely difficult to change the chain with the cams in their normal place, I have tried and failed!

    After gaining access to the cams remove the timing adjustment pins from the cam sprocket, and loosen the bolts that secure the sprockets to the cam so they can turn on the cams. Wind off the tensioner to give some slack in the chain. Loosen all the cam bearing nuts to let the valves remain more or less in their seats, then connect the new chain to the old one. I think it is better to do this on the tensioner side, then draw the chain over all four cam sprockets by winding the engine over from the bottom pulley on the crank.

    This is a two people job, get someone under the car turning the engine in it's normal running direction, and someone feeding the chain in, and pulling the old one out on top.

    You could just pull the cams out completely, but I found they helped to support the chain as it is wound in if they are still there. It was a couple of years ago I did this and I cannot remember if I had to remove all the bearing caps to allow the engine to turn without valve/piston contact, or if it was enough just to loosen them and let the cams rise.

    While you are inside the cam covers you can reset the valve clearances, and obviously get the valve timing spot on. I would get the chain tension roughly right static, and finally adjust to optimum with the engine warm and running.

    This is a fairly long job as you have to remove a lot of plumbing and parts to get at the cams, but you can be sure of getting their in the end!
     

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