Forums General Counties Cars Discussion A70 torque settings

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  • #5141
    ToadofToadHall
    Participant

    Hi all,

    I am rebuilding a 2.2 litre engine and looking for some advice. There are no torque settings for big end and main bearing nuts. I found a pdf on here with torque specs but the A70 column is blank.

    The manual I have simply says to fully tighten them. I am a little afraid of over or under tightening them.

    Does anyone have a technique or torque they have found successful?

    Many thanks

    #5143
    PeteJS
    Keymaster

    I don’t have anything specific to the A70 or the Sixteen, but the specs for the Healey 100 engine, which is very similar, are:

    Big end caps (piston rods) are 50 ft-lbs
    Main Bearing Caps 75 ft lbs.

    #5145
    ToadofToadHall
    Participant

    Hi Pete.

    Yes just been looking at those online. I was thinking 50 ft lbs for the big ends and 65 for the mains. Might be an idea to sneak up on the mains, maybe see how it feels getting them to 60 and go from there.

    The 100/4 gives 75 ft lbs for the cyl head but in my manual it says 65 ft lbs for the head nuts. So perhaps slightly under 100/4 spec and shouldn’t be too far off the mark. Not sure if that makes any sense.

    Thanks, Paul

    #5147
    number5
    Participant

    Whilst it would be possible to overtighten the cap bolts,  the engines that have split pins to secure the caps don’t have torque values as the parts are machined to tollerances that take the thicknesses of the shells.  Once the mating surfaces are seated, the only requirements is to tighten to ensure that the nut aligns to the nearest split pin slot.  Once the faces are secured, the “fixed” diameter for the bearing shells remains constant.

    Not sure when it was instigated, but later A70 were fitted with nyloc type nuts, as were many BN-1 Healeys,  although my BN-1 still had split pins on all of the caps. My Healey manual still references the caps fitted with split pins.  I have undertaken a number of the 2.2 and 2.6 engines over the last 55 years, and never had any hassles with the shell caps.  Always though,  be sure to use new good quality split.

    Happy days-Peter.

     

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