Arp main studs

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  • pasbogdan
    S2Forum Extremist
    • Sep 2009
    • 1160
    • Country: Romania

    #1

    Arp main studs

    Do you know something about shortening main stud/studs at main cap nr 3 or removing "ceck valve" when installing arp mains?
    Time has come to put engine together and i was getting info about torques and recived this info..
  • G60Rallye
    S2Forum Extremist
    • Dec 2006
    • 1321
    • Country: United Kingdom

    #2
    If you do a search on here it has been covered before. If you remove the restrictor and screw the stud in you will get an idea of how much it needs to be shortened.

    Comment

    • pasbogdan
      S2Forum Extremist
      • Sep 2009
      • 1160
      • Country: Romania

      #3
      I screw the stud hand tight and the nut is level with the top of stud when installing cap.What am i missing?All nuts are level with studs at each cap,not just nr 3.And the valve is in its place

      Comment

      • Trankelstein
        S2Forum Enthusiast
        • May 2008
        • 119
        • Country: Sweden

        #4
        stud

        Sounds like your checkvalve´s already removed if you can screw the stud until flush with the cap? either that, wrong studlenght or your checkvalve is quite crushed!

        Some people claim their ARP main stud kit contained one shorter stud (my kit didn´t!), the shortest stud should then go into the no 3 bearing hole that is connected to the oilchannel.

        Best to remove oil pressuresender, thread adapter and checkvalve (the torxscrewed one inside the hole) and use a flashlight so you see the stud coming from above (assuming engine is upside down). Either way don´t reuse a checkvalve that you suspect have been damaged by the stud, the ballvalve inside seize easily and the results when starting is not funny! it´s quite cheap to buy new
        sigpic
        80 quattro 1984..... S2 sedan 1994

        Zermatt silver......... Brilliant black

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        • pasbogdan
          S2Forum Extremist
          • Sep 2009
          • 1160
          • Country: Romania

          #5
          The valve is in its place,got it out it is not damaged.All studs have same lenght and all get leveled with nuts when installing caps and shims.All stud bores are2/3mm deeper than the one with the valve but the studs do not get to the bottom because of flat end of stud versus conical shape of bore.That is why i think all get the same lenght..I do not imagine something else.I will ceck deeper but i think it is nothing to modify.Thank you for answering

          Comment

          • V6quattro
            S2Forum Maniac
            • Sep 2008
            • 949
            • Country: Netherlands

            #6
            Here are some photo's of mine. The APR mains are from 034 :corey: and already had a sorter stud. Just make sure you have the stud fully in and don't hit the valve.

            And how much torque do you set them? I did 88Nm (65ftlb).
            But i had some problems with bearing clearings when tighten to 88Nm. So i had my mains's line honed.
            1360kg/600Whp Avant 0-200km/h 9sec

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            • V6quattro
              S2Forum Maniac
              • Sep 2008
              • 949
              • Country: Netherlands

              #7
              The photo's
              Attached Files
              1360kg/600Whp Avant 0-200km/h 9sec

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              • pasbogdan
                S2Forum Extremist
                • Sep 2009
                • 1160
                • Country: Romania

                #8
                Torque to 90nm(i always add a little more).Also i try to get a little more with short tool to torque(because nm torquing tool has 1 meter long ) because i like to feel in my hand what is going on with the screws/studs/nuts.But guess what?At 90nm torque clearance is about 0.05mm.If i try to push a little more(2 or 3 degree,just a little as my hand feels it will go further) clearance becomes 0.03 mm.So to tight.
                About torque..
                I checked h beam rods for roundness and caps were tighten just a little.I got scared:0.03 mm +at longitudinal measurement.After torquing to spec it got round.Those arp tighten things,not only joking

                NOW I SEE..
                My all mains are short.Yours are not.The nut is fully engaging screw but nothing remains outside
                Attached Files
                Last edited by pasbogdan; 21 September 2012, 21:30.

                Comment

                • Trankelstein
                  S2Forum Enthusiast
                  • May 2008
                  • 119
                  • Country: Sweden

                  #9
                  Sorry, i realize i misinterpreted you, thought the studs went flush with the bearingcap

                  Sounds like your conclusion is right, but as long as all threads are engaged nothing to worry about i would think?
                  sigpic
                  80 quattro 1984..... S2 sedan 1994

                  Zermatt silver......... Brilliant black

                  Comment

                  • pasbogdan
                    S2Forum Extremist
                    • Sep 2009
                    • 1160
                    • Country: Romania

                    #10
                    What about nuts flush with studs?I am not an engineer but i noticed all automotive builders use screws that get a little further than nuts,specially in important areas.Usually no screw is flush with nut.I imagine it is something about strenght and internal tensions in the screw/stud.It is as this for easy mounting also but something has to do also with strenght.I imagine millions of screws shorter would mean money but they do not do it.
                    What do you advice?

                    Thank you

                    Comment

                    • pasbogdan
                      S2Forum Extremist
                      • Sep 2009
                      • 1160
                      • Country: Romania

                      #11
                      Does anybody have any feedback for this short studs?

                      Thank you

                      Comment

                      • stocious
                        S2Forum Maniac
                        • Jul 2012
                        • 838
                        • Country: Ireland

                        #12
                        back the studs out a thread or two ? are they the same thread either end ? some of the studs in your pic look like they are a thread or two below the nuts !! seems odd that some are flush and some are not even on the same cap ? as far as i know a stud does not have to be bottomed out or even tightend for that matter, finger tight if anything. im gonna say back out the studs a little untill you get same height on all of them with at least a thread or two above nuts! or first of all check your part# with a known good stud set used by someone on here. hope this helps.. probably not
                        1991 S2 3B Coupe, KW v1, solid sub frames, poly bushed, chipped, about 260 ish

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