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Maserati Mistral Timing Chain Tension

Discussion in 'Maserati' started by Ettore66, Jan 28, 2020.

  1. Ettore66

    Ettore66 Rookie

    Oct 23, 2015
    18
    Orlando, FL
    Full Name:
    Michael Coffman
    I urgently request help in determining the correct tension for my 4-liter Mistral timing chain. Measured from the edge of the cam cover to the maximum deflection I measure 2-inches, and with the chain tensioner at its maximum tightness I measure 1 1/2-in. Measured horizontally between the two cams, 1-inch separates the top of the chain to the edge of the cam cover. This chain tension obviously affects the engine timing and is critical to valve/piston interference. This chain is however a new replacement and I am concerned it is not correct for an injected engine. Image Unavailable, Please Login
     
  2. Heymj73

    Heymj73 Rookie

    Jun 24, 2019
    5
    Full Name:
    Mathew Jonston
    Hi,
    this pertains to the V8, but there will likely be similarities. I just finished doing valve shims on my 4.7. There are some links below that may be helpful, plus i remember coming across tensioner info for the inline 6 as well if you search the forum.
    With mine i set the timing chain tensions before dialling the cams in. I spent considerable time turning the engine over as if it were running and moving the slack to the tensioner, i.e. took the slack out of the 'drive' side of the camshaft chain. There was ample adjustment in the tensioner to remove this 'totality' of slack, the manual calls for around 10lb/ft on the tensioner eccentric. Everything, i.e. all bits of the chain i could access, felt 'firm' nce this was done. As you point out the tension is critical for camshaft timing. I then reset the camshafts after the tension was set. The engine runs well. Good luck and perhaps others have actual measurements.

    https://www.ferrarichat.com/forum/threads/maserati-4-9-v8-engine.246454/page-10

    https://www.ferrarichat.com/forum/threads/4-9l-time-saving-tips-for-timing-chain-adjustments.392395/
     
  3. Ettore66

    Ettore66 Rookie

    Oct 23, 2015
    18
    Orlando, FL
    Full Name:
    Michael Coffman
    Sincere thanks for your reply. I agree the slack must be removed from the drive side of the chain, requiring any movement of the crankshaft to be in total sync with the cams. In checking some of the Maserati parts sources in the event a new chain was necessary, I was intrigued by the listing in the Heinbrand.com list that shows two different chain tensioner sprockets for the inline-6, one with 21 teeth and another with 24 teeth. This variation may be great enough to account for the slack I'm having a hard timing removing. The parts manual does not show separate parts listings for these different timing chain sprockets but somehow a Maserati expert in Aachen, Germany figured it out I will now remove my timing chain sprocket and attempt to locate a chain that matches it and go from there.
     

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