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Re-torquing fresh ARP head studs after first race on NA KA24DE...

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  • Re-torquing fresh ARP head studs after first race on NA KA24DE...

    Just wanted to read some thoughts about re-torquing newly installed ARP head studs that were put in during head gasket service (OEM head gasket) after the first use/heat cycling period (i.e.-endurance racing weekend).

    I know this is recommended practice for some engines by factory service procedures. Generally, I believe they are aluminum block engines. However, would you recommend, or not recommend, doing this on a race car with an NA KA24DE that saw almost 20 hours track time after the initial installation?

    All ARP procedures (with ARP fastener lubricant) were followed when installing the studs.

    Cheers,
    Tom
    Core4 Motorsports
    CLICK HERE for Wilwood FSL6R Radial Bracket & Rear Wilwood BBK GROUP BUY
    S14 VQ AER Endurance Racing Team

  • #2
    It isn't as if you are seasoning a NEW block. and the iron block shouldn't change temper as if it were aluminum.

    If I were to "retorque" them I would loosen in factory specified order then re-torque per ARP specs

    Personally, I wouldn't be bothered with it. for whatever that is worth.
    I am SKULLWORKS

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    • #3
      The purpose of retorquing thermally cycled fasteners is that residual friction/misalignment will usually get "removed" during the thermally cycling process. So it is entirely normal to retorque the fasteners after a few heat cycles.

      ARP knows their chit. Do what they say.
      '18 Chevrolet Volt - Electric fun hatch for DD duty!


      DefSport Koni Sleeve and Spring Perch Buy!!!
      http://www.nissanroadracing.com/showthread.php?t=5902

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      • #4
        Originally posted by Def View Post
        The purpose of retorquing thermally cycled fasteners is that residual friction/misalignment will usually get "removed" during the thermally cycling process. So it is entirely normal to retorque the fasteners after a few heat cycles.

        ARP knows their chit. Do what they say.
        We are leaning toward re-torquing. I'm going to call ARP and see what they recommend for our application. Will update here...
        Core4 Motorsports
        CLICK HERE for Wilwood FSL6R Radial Bracket & Rear Wilwood BBK GROUP BUY
        S14 VQ AER Endurance Racing Team

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        • #5
          When I've retorqued ARP studs in the past, I've done it in factory order by breaking one loose and then retorquing before moving to the next one. I've had luck in not disturbing the oil and coolant galleys by doing it that way. See how ARP recommends to proceed as I'm curious. My method was learned from working with veteran mechanics.

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          • #6
            Just got off the phone with them. Re-torquing after the fist heat cycling of new head gasket install is to compensate for the compression of a fresh head gasket. Nothing was mentioned of residual friction or mis-alignment, although I didn't ask about those issues. This is probably based off of the assumption that all threads were inspected, cleaned, and their assembly lubricant was used.

            He mentioned that some head gasket manufacturers claim it isn't necessary to do it. I used OEM, I'm going to do it. He said to just back off the nuts about 1/2 turn, then preload them back to spec in factory recommended order so it seems like you were pretty much on the money, Hijacker. Since our first heat cycling was an entire endurance racing weekend, we're going to do it, ha!
            Core4 Motorsports
            CLICK HERE for Wilwood FSL6R Radial Bracket & Rear Wilwood BBK GROUP BUY
            S14 VQ AER Endurance Racing Team

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            • #7
              Yes, the gasket plays a role, but even in a circumstance with two rigid surfaces bolted together - you thermally cycle it a few times and you'll typically lose a small amount of torque on a decent percentage of the fasteners.
              '18 Chevrolet Volt - Electric fun hatch for DD duty!


              DefSport Koni Sleeve and Spring Perch Buy!!!
              http://www.nissanroadracing.com/showthread.php?t=5902

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              • #8
                My application isn't NA, but I was pressurizing my coolant system with ARP's and a fel-pro head gasket on my KA. It wasn't until I loosened them all and re-torqued them in the specified order that the problem was fixed.

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                • #9
                  Originally posted by Def View Post
                  Yes, the gasket plays a role, but even in a circumstance with two rigid surfaces bolted together - you thermally cycle it a few times and you'll typically lose a small amount of torque on a decent percentage of the fasteners.
                  Absolutely. Every head gasket job I've retorqued, the fasteners will move usually a quarter turn to a half turn past where it was on the initial torque.

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                  • #10
                    I know this is an old post, but I can tell you from experience on my CA18, I HAVE to re-torque the ARP head studs every time I have ever pulled the head. They ALWAYS loosen up after a heat cycle. I don't know why the KA would be that much different.

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                    • #11
                      Follow nissan procedure, use arp torque values

                      Every time you change the headgasket, nissan specs torquing in stages, warming up the engine fully, and backing off halfway, retorque again... if you follow that, nothing should ever blow

                      Remember the arp studs will stretch even less than the headbolts would
                      http://responsetype.com/shop/

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                      • #12
                        Bringing this back with a related question.

                        I'm pressurizing my coolant system in boost, engine is a KA with ARP studs and a Cosworth head gasket. Temps never got above 195 so I'm ruling out a warped head, I did hit overboost protection though (22psi) early on in the day. No coolant in the oil, no smoke from the exhaust, idle/normal driving is perfect, however the coolant has an oily sheen to it.

                        I'm hoping to get away with just re-torquing the head, it's worked for me before however that was with a fel-pro head gasket. It seems like the consensus was to loosen and re-torque the studs one at a time in factory order as to not disrupt the coolant and oil passages. Since I already have a leaking coolant passage should I loosen them all before re-torquing, or should I just do one at a time.

                        It might also be worth noting that I hit overboost protection around 10 am, I continued driving until around 1:30 pm without issue. It was only after I let the car cool down for ~3 hours and went back out on track that the problem presented itself.

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                        • #13
                          Same on an SR20 with Cosworth HG? Lot of work to pull the cams but a bad step to skip.

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