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Thread: Head bolt torque

  1. #1
    Join Date
    Dec 2010
    Location
    Mirboo North Victoria
    Posts
    429
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    Head bolt torque

    I have been running my new motor briefly to check it’s operation and test clutch and gears, so far the motor has run approximately one hour. My question is has anyone had issues with head torque, specifically re-torquing. After initial assembly where I torqued the head to manufacturers specifications I decided to check the bolts two weeks later even though I hadn’t operated the motor. To my surprise the bolts moved approximately 1/8 of a turn, after installing the motor and test running I again checked the bolts they all moved without me overcoming any resistance. The head gasket is a copper composition two layers of copper with some material between the layers, I have been a heavy diesel mechanic for over fifty years and rebuilt multiple engines over that time. I have never experienced this bolt movement before, I don’t remember the last time I installed a copper composite head gasket as they were originally manufactured with asbestos as the fill material between the copper layers and as such were deemed a health hazard and discontinued. I do remember some stationary Diesel engines having composite gaskets on the head and exhaust manifolds but I do not remember having any torque issues after initial test running and obligatory re-torque and tappet reset. Has anyone experienced this problem and did it resolve itself after engine run in or do I keep checking head bolts. The bolts are not damaged and there is no evidence of waisting ie thinning of the shank I removed two bolts to check.

  2. #2
    Join Date
    Nov 2015
    Location
    Black Rock
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    993
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    You're testing my memory, and I'm assuming you're talking about the 2.25 petrol engine, but I used to torque to 65ft/lbs and let it run for a day or so and then recheck the torque by backing each bolt off a fraction and re-torquing to spec. 1/8th of a turn sounds about right. It never occurred to me to do it again! I wonder if I would have found the same as you?
    I recall using both the original copper head gaskets and the (then) new you beaut composite ones. From memory, I used Hylomar on the copper ones but I forget if the composite ones were meant to be installed dry. If not, I would have used Hylomar, too.
    I'd be inclined to let the motor run for a week or two (assuming it gets driven every day) and check again. If it's not nice and snug then there may be an issue with the gasket.
    The last series engine I worked on was a SIII 2.25 diesel. I don't recall the head gasket material, but it torqued up fine and the re-torque was probably a waste of time as it was nice and snug anyway.
    2013 D4 expedition equipped
    1966 Army workshop trailer
    (previously SII 2.25 swb, SIII 2.25 swb & lwb, P38 Vogue, 1993 LSE 3.9V8 then HS2.8)

  3. #3
    Join Date
    Sep 2012
    Location
    Westlake ,brisbane
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    This is normal, I was taught as an apprentice motor mechanic to retorque cylinder head after 1000miles. Back then 55 odd years ago when new vehicles came in for there After Sails Service 1000miles you retorqued the head bolts & they would need about 1/8 of a turn. Also, overhead rockers would need adjusting along with checking all bolts on suspension, it was all part of the A.S.Service.

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