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1G Torque plating the cylinder head.

Posted by SasaniFab, Jul 12, 2020

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  1. SasaniFab

    SasaniFab Freelancer

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    I was having a conversation with Jeff bush and he mentioned that he torque plates the block as well as the head. I can’t imagine that many of you have considered doing that to the head. For fun I decided to torque plate a head to check for distortion and I couldn’t believe how much the valves moved. Jeff also mentioned that Hes NEVER gone over 99 ft lbs with head studs and that over torquing will the distort the head . He said that’s the #1 mistake guys make. I’m really tempted to put a motor together and do a leakdown at 98 ft lbs and again at 110. I’ve always torqued the head to 110 with l19s. I probably get away with it because my motor is torqued plated At that spec. I wonder how many guys are creating head gasket issues on stock motors with arps. It is very possible that they are distorting the head.
     

    Street Build 4K  20

    1992 Eagle Talon TSi
    645 whp · 498 lb/ft · 1G DSM
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  2. JCL84

    JCL84 Proven Member

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    McHenry, Illinois
    I was told by an engine builder that if you over torque the head that you can actually suck in the cylinder walls.
     

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    1995 Mitsubishi Eclipse GSX
    manual · 2G DSM
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  3. bastarddsm

    bastarddsm Proven Member

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    torque plating the head is a fools errand. think about how much it moves around when there is 5000psi in the cylinder.
     

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    1991 Eagle Talon N/T
    9.805 @ 144.00 · 1G DSM
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  4. SasaniFab

    SasaniFab Freelancer

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    YAh, id never go that far, I did however time sert a block for 1/2 studs. From the reading I’ve done it’s not necessarily the increased torque capacity of the stud but the increased distribution across the deck. Moving the studs closer to the cylinders that is. How much this helps ? Guess we’ll find out
     

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    1992 Eagle Talon TSi
    645 whp · 498 lb/ft · 1G DSM
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  5. jed344

    jed344 Supporting VIP

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    Waterville, Iowa
    I never go over 100ftlbs with L19's or any stud on a dsm. I have seen to many issues in other platforms when people think tighter is always better with head studs. I think the motor im using right now is at 95 ft lbs with l19's, 0 ringed head, OEM composite gasket.
     

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    1997 Mitsubishi Eclipse GSX
    awd · manual · 2G DSM
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  6. motomattx

    motomattx Proven Member

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    Torque plate the head and do WHAT with it? so you bolt a torque plate to the head and then??? you cant resurface the head with the torque plate bolted to it obviously, redo the seats with a torque plate bolted to it? then what happens when 210 degree coolant runs through the aluminum head? the head moves more from that than it does being bolted to the block, also the block is steel, so you would have to use a steel torque plate like I had made to simulate the load of the steel block, bolting an aluminum plate to an aluminum head at room temperature would only make the head way off in terms of being true after you bolt it to a steel block and run it at 210 degrees or more.
     

    Drag Race Build 4K  24

    1995 Mitsubishi Eclipse GST
    fwd · manual · 2G DSM
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  7. RWD4G63

    RWD4G63 Proven Member

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    The solution is to simply not torque the head down that hard. The reason you run L19 or 625+ studs is because the material is stronger, not because you can clamp the head harder. Yes, the valves will move and yes, you will crush the head stud areas in the head if you torque it more than 90ish ft/lbs. Just don't do it.

    The reason you torque plate a head is to get the valve seats cut properly so they are 100% accurate when the head is on the block. This is a big issue with some engines and not a big deal for others.
     

    Road Race Build 317  3

    1997 Eagle Talon TSi AWD
    awd · manual · 2G DSM
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  8. donniekak

    donniekak DSM Wiseman

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    Like mentioned already, there is several thousand psi of pressure trying to keep the valve closed.
     

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    1991 Eagle Talon TSi AWD
    manual · 1G DSM
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  9. motomattx

    motomattx Proven Member

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    On steel V8 heads sure, but not really on our heads that grow all over the place with heat, and agree with over torquing head studs. or any other type of fastener that is critical, people develop the mindset that if some is good then more must be better and its the opposite with bolts, you ruin the stretch on the bolt and neck it and you ruin the area that the bolt clamps to, the same with putting glue on a head gasket, if you think that you need to do these things, then you have a problem that you need to address properly, not by rigging it with hocus pocus bs, do it right or dont do it, does anyone think that John Forces car has gasket spray or over torqued bolts on it anywhere? how about Kyle Bush's car? how about Andretti's cars?
     

    Drag Race Build 4K  24

    1995 Mitsubishi Eclipse GST
    fwd · manual · 2G DSM
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