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Thread: A.R.P. Stainless Bolts Backing Out

  1. #1

    Steve >> aka: GoDadGo
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    A.R.P. Stainless Bolts Backing Out

    Hey Gang,

    1. Have any of you had any issues with Stainless Hardware backing out?
    2. Specifically, I am looking for information when dealing with Aluminum Intake Manifolds and Aluminum Valve Covers installed on Iron Heads?
    3. I've got an issue that I'm working through on the Chevy Cobra and wanted to hear from the group regarding this subject so please chime in.
    4. If you do information and have any comments, suggestions or solutions then please share them with me.

    Steve

    PS: I'm Running Iron Eagle Heads On A Stock Iron Block!

  2. #2
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    Hi Steve,
    Can't say I've had that problem specifically. Could it be that the gaskets are taking a set? Are these bolts or studs? You can locktite studs in.
    I have had problems with bolt heads digging into aluminum manifolds on that other brand of engine, so torque would not stay consistent. Had to put washers under them.

  3. #3

    Steve >> aka: GoDadGo
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    Quote Originally Posted by PeteH View Post
    Hi Steve,
    Can't say I've had that problem specifically. Could it be that the gaskets are taking a set? Are these bolts or studs? You can locktite studs in.
    I have had problems with bolt heads digging into aluminum manifolds on that other brand of engine, so torque would not stay consistent. Had to put washers under them.
    > All hardware was ARP Stainless Bolts with ARP Stainless Washers underneath.
    > No Studs on the Aluminum Intake which were installed on Iron Eagle Dart Heads.
    > The Intake bolts were torqued between 25-30 lbs when originally installed, but backed off to about 10-12 pounds.
    > Had to turn roughly 1/4 turn to click the torque wrench at 15 pounds.
    > I've burned around 9 gallons of fuel just breaking things in and have now driven between 25-30 miles.
    > Lots of starts and runs up to operating temperature, then shut down and/or parked until the next weekend.

    The question is: Did they stretch or did they simply back out via heat cycling like header bolts?

  4. #4
    Seasoned Citizen NAZ's Avatar
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    Can't say I've had any more problems when using SS fasteners vs cad plated steel on intake manifolds and valve covers. One of the problems is the gasket compliance from these rather thick gaskets that will diminish the pre-load over several heat cycles. I usually have to re-torque all these fasteners at least once after the first dozen or so heat cycles. A fastener works like a spring -- it stretches when tightened and that pre-load helps to keep it from backing off. Loose the pre-load and you have a loose fastener that vibration will tend to spin even looser. You can use the penetrating type thread locker (the minimum strength stuff) on these fasteners. Or what I use on the valve covers is a serrated flange nut that helps keep the cap screws from loosening. I like to run 4" (or longer) cap screws on my valve covers with a flange nut spun to the end of the thread and tightened before installing the fastener into the head. These longer fasteners are much easier to get off for adjusting valves. Obviously the flange side goes against the valve cover. This longer cap screw (bolt in layman's terms) puts the hex head higher where it's easier to get a wrench on them and when loose, your fingers on them so you don't drop them. On the SBC I also use the old Corvair style spreaders on stamped valve covers to distribute the cap screw load over a larger area. This keeps from distorting the sheetmetal (causing leaks) and minimizes gasket compliance. They're not really needed on the thick cast aluminum valve covers.

  5. #5
    Member JRD56's Avatar
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    I've built a lot of hot rods over the years and have always had to re-torque intake bolts, particularly on aluminum intakes. I usually have to do this twice. I've always believed it was due to the heat cycle as mentioned above. I've used various types of fasteners but have always had to re-torque them all.

  6. #6
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    Steve,

    It is normal to retorque those manifold bolts a few times from the heat cycles.

  7. #7
    Senior Member Lowrod's Avatar
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    If using locktite make sure you use the cleaning spray, it has an additive that ensure curing when used on nonferrous metals.

  8. #8

    Steve >> aka: GoDadGo
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    Thanks Gentlemen For Your Comments!

    They are appreciated.

    Steve

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