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    Default Standard head gasket thickness

    hi,
    anyone knows what is a standard head gasket thickness?

    regards

    WS

    arrghh... Steve can You please move this thread to proper forum section? my bad...
    "Never take life seriously. Nobody gets out alive anyway."

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    Moved to Q4 Tech

    wrinx
    My Q4 in the Garage

    www.alfaromeo155.co.uk ............................ □□□-V-□□□ .................................. www.ilmostro.co.uk

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    Standard head gasket is 1.9 mm

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    Standard head gasket is 1.9 mm
    I confirm mpampis's input, its 1.9mm.

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    So how much difference does fitting a 1.6mm head gasket make? It the extra compression noticeable?
    1994 Alfa Romeo 155 Q4: Dozeing in the garage.
    2009 Audi A4 tdi: Everyday drive.
    1994 Alfa Romeo 155 , 1995cc Std Standard Black

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    Quote Originally Posted by Steve Webb View Post
    So how much difference does fitting a 1.6mm head gasket make? It the extra compression noticeable?
    Im trying to calculate
    many engine compression ratio calc on internet

    1.9 mm to 1.6mm
    8:0 cr to 8.17 cr

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    As Hakan (maxiboost) say above 1.17. Not only in theory but in practice too. I have 1.6 head gasket and I measure CR after rebuild

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    Quote Originally Posted by mpampis_ View Post
    As Hakan (maxiboost) say above 1.17. Not only in theory but in practice too. I have 1.6 head gasket and I measure CR after rebuild
    mpampis, you need measure "before" engine rebuild
    like this:
    http://www.automedia.com/Checking_Co...ht20020701cr/1


    you can cylinder compression test, after the rebuild engine
    its not compression ratio, its cylinder pressure test

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    We measure it with petrol for a compression ratio, not compression in cylinders. I have 12 bar compression

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    Quote Originally Posted by mpampis_ View Post
    We measure it with petrol for a compression ratio, not compression in cylinders. I have 12 bar compression
    mpampis could you explain more please ?

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    Without camshaft we put gas to the first cylinder from the spark plug hole when piston 1 is on the top dead point. After we put gas in the 2 cylinder when the piston is on the down dead point and with that way we put the compression ratio at 8.2:1

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    mpampis_, are you sure for 1.9
    because all after market gaskets are 1.78 before fitting

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    I'm sure 100%. On the other hand I didnt see anywhere 1.78

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    You make me change my opinion I had all these years.... Who knows then. Maybe you are right. For me Everyone who asked for a head gasket they sell as oem part 1,9 mm

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    Quote Originally Posted by mpampis_ View Post
    Without camshaft we put gas to the first cylinder from the spark plug hole when piston 1 is on the top dead point. After we put gas in the 2 cylinder when the piston is on the down dead point and with that way we put the compression ratio at 8.2:1
    wow its a fantastic method
    but any gasoline leak from piston rings ?

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    No, specially when the pistons and rings are new and as they have to be

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    HP hfe the gasket in the picture seems to have 85mm diameter. Are you sure that the characteristics are for OEM engine? It should have 84 mm diameter.

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    yes the oem gasket is with 85mm rings, the bore is 84mm
    most racing gaskets are 85mm too
    spesso have 86mm to

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    It's 1.9mm.
    Putting a thinner HG on without any other mods will increase the risk of the piston hitting the head, it's only 1mm away as standard.

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    Have anybody measured an old gasket that was removed from an engine? Because composite gaskets compress about 20 - 25%. On the Alfa TS a new composite gasket is about 2 mm and it compresses to 1.6 mm.

    A thinner gasket will make the risk of detonation higher on an hard working engine, but I can't say by how much.

    I don't believe the piston will touch the valve yet, unless when the head was resurfaced and lot of material was removed.

    When the piston hollow and combustion chamber are measured the volume of the gasket space must be added. Both methods of measuring is good, but we found it more accurate before assembly.

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    when I measure my was 1.6
    but don't know is the engine overhauled

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