Ferrari 400/412 Timing Chain Adjustment | FerrariChat

Ferrari 400/412 Timing Chain Adjustment

Discussion in '365 GT4 2+2/400/412' started by 360modena2003, Mar 20, 2022.

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  1. 360modena2003

    360modena2003 Formula 3

    Jul 11, 2009
    2,329
    Now that the engine is running as it should, I was able to accelerate it and I believe I heard the timing chain rubbing against the timing chest. I have removed the small cover and can see a bit of wear against the aluminum.

    My car has barely over 30,000KM, so I assume the chain is original - the guides are in very good condition.

    The adjustment screw is standing proud by at least 20/25mm, so there is adjustment left. I read somewhere that the screw should have at least 5mm thread showing, otherwise the chain needs to be replaced (although not mentioned anywhere in the WSM).

    My question is, how much slack should there be measured between the two camshaft sprockets? (at #8).

    The "adjust until noisy and then 1/4 turn back" method is with the engine at idle, the "noise" I take it is a "grinding"/high friction sound from an over tightened chain - any suggestions here?

    Interesting to note that the WSM mentions up to 0.7% of stretch is permissible.

    Another point of inconsistency (unless something was improved and this was the intention), is that the 400i WSM calls for timing chain adjustment (restore) every 5000km, whereas the 412 owner's manual states to only "check" every 10,000km.



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  2. raemin

    raemin Formula 3

    Jan 16, 2007
    1,825
    Lyon (FR)
    Full Name:
    R. Emin
    Somewhere in the WSM, the adjustment is better explained, if you apply a 10kg pull to the chain between sprookets 13 and 14, the deflection should be less than 1cm (not sure about this last figure).

    The tensioner mechanisme is slightly different on the 412 (see @Al Campbell post), so it does not protrude the same way as the tensioner described in the WSM (less protrusion in the 412 if I understood correctly).

    Marks on the aluminium are not good.

    Do you have the records that do certificate the mileage? 30.000km on the oddometer could well be 130.000km on the asphalt.

    The newer oils were better for cold start wear, but worse for the chain, that's maybe the reason why the maintenance of the distribution is different on the 412, but such shorter period seems overkill.

    Finally you should read the instruction in Italian, as the English ones were messed up (and say exactly the opppsite as far as chain tension is concerned!).
     
  3. 360modena2003

    360modena2003 Formula 3

    Jul 11, 2009
    2,329
    #3 360modena2003, Mar 20, 2022
    Last edited: Mar 20, 2022
    Thank you raemin, as usual very valuable contribution. Do you have the link for the post from Al Campbell, I was not not able to find it.

    I am quite sure it has 30,000km, as it stood for a very long time. I have some records from 1995 to 2002, after which the car stood for a very long time.
     
  4. 360modena2003

    360modena2003 Formula 3

    Jul 11, 2009
    2,329
  5. 360modena2003

    360modena2003 Formula 3

    Jul 11, 2009
    2,329
    What is the current consensus on where to buy the chain, GY06B2 - Renold Synergy Chain?

    Sent from my MAR-LX1M using Tapatalk
     
  6. SouthJersey400i

    SouthJersey400i Formula 3

    Mar 14, 2007
    1,591
    Romulus, NY (Finger Lakes)
    Full Name:
    Ken Battle
    360
    Did you look at the condition of the rubber on the chain tensioner? It can finally to to bare metal (on 400i). Changing tensioner is a lot more work than the chain. Do not over-tighten chain; it will wear the tensioner more than the chain! (Lesson learned!)
    Ken
     

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