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  • Timing Chain Cover

    I have a question for some of the experienced mechanics. I have a 1998 Lumina 3.1L and have replaced the timing chain cover gasket, the first time I replaced it was over 5 years ago and went well from what I remember. This time I was confident that it would be easy. I have a Chilton's and a Hayne's manual for this vehicle, same company prints both manuals. The Hayne's lists (for 1998 & 1999) three bolt sizes for the timing chain cover: small (15 ft-lb), medium (35 ft-lb), and large (41 ft-lb). There are three sizes of bolts on the cover if you count the two small bolts that hold the crankshaft position sensor. After installing the cover and the balancer, I noticed that the Chilton's shows only small cover bolts (15 ft-lb) and large cover bolts (35 ft-lb).

    I have already cranked the small??? or medium??? to 35 ft-lbs. The small bolts holding the crankshaft sensor basically tore the plastic mounts on the sensor and now I'm wondering if the small or medium bolts (whichever they are) should have been torqued to 15 ft-lbs instead of 35 ft-lbs. I don't think any threads gave during install, but what is the actual torque specs for these bolts and do I need to back them off to 15- ft-lbs.

    This could be a real mess and I'm not happy at all with the Haynes manual.

  • #2
    After looking at the torque specs on this website, it looks like the smaller bolts should have been torqued to 15 ft-lb (as Chilton's said) and the crankshaft sensor to 89 in-lb.
    I AM NOT HAPPY WITH HAYNES!!!

    What are my options??? Have I screwed up threads? Can I back out the bolts, put some thread locker on and put them back in at 15lb-ft? I need a little professional mechanic advice. Have I stressed the timing chain cover and warped it?

    Comment


    • #3
      You can loosen them off and re-torque to proper specs, you will probably want to replace the crank position sensor since you say it has physical damage. Note that teh CPS has it's own torque specs are not included as "front cover bolts".

      To be honest though, I don't typically torque the front cover bolts, just tighten them by hand, until a bit past snug. *shrug*

      Why are you not likely the Haynes manual, it sounds like the torque specs are the same, at least for the small and medium bolts, and there are 3 different size of bolts, on the gen3 engines.
      James: 1985 GMC Jimmy, 3.2L turbocharged, intercooled hybrid 13.873 @ 99.08 218HP & 270FT/lbs @ the wheels
      The Daily: 2000 GMC Yukon
      1973 Datsun 240Z: Turbo intercooled LX9, running on '7749 with $59 and DIS. 12.71 @ 115

      "If you're not living on the edge, You're taking up too much space."

      Still waiting for the 1st or second Ostrich I was promised, from Paul.

      Comment


      • #4
        You can loosen them off and re-torque to proper specs, you will probably want to replace the crank position sensor since you say it has physical damage. Note that teh CPS has it's own torque specs are not included as "front cover bolts".

        To be honest though, I don't typically torque the front cover bolts, just tighten them by hand, until a bit past snug. *shrug*

        Why are you not likely the Haynes manual, it sounds like the torque specs are the same, at least for the small and medium bolts, and there are 3 different size of bolts, on the gen3 engines.
        James: 1985 GMC Jimmy, 3.2L turbocharged, intercooled hybrid 13.873 @ 99.08 218HP & 270FT/lbs @ the wheels
        The Daily: 2000 GMC Yukon
        1973 Datsun 240Z: Turbo intercooled LX9, running on '7749 with $59 and DIS. 12.71 @ 115

        "If you're not living on the edge, You're taking up too much space."

        Still waiting for the 1st or second Ostrich I was promised, from Paul.

        Comment

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