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1.8T compression test (values)

Discussion in 'A3/S3 Forum (8L Chassis)' started by luis.filipe, Oct 22, 2007.

  1. luis.filipe
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    luis.filipe Member

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    [Oct 22, 2007]
    Hello,

    during the last week I took my 1.8T (AGU) to perform a oil pressure test
    and a compression test.

    The oil pressure test was fine, here are the values.

    Idle - 1.5 bar (minimum was 2.0 bar)
    2k rpm - 3.0 bar (values between 3.0 and 4.5 bar)
    4k rpm - 4.0 bar
    5k rpm - 4.0 bar

    Only at idle speed we have less than what is written on Haynnes service manual.

    Regarding the compression for a AGU engine when new we should expect something like 9.5:1.

    Now here are the values that I got on the test:

    Cylinder 1: 13.0
    Cylinder 2: 12.75
    Cylinder 3: 12.5
    Cylinder 4: 13.0

    Those values are very high for this engine and I will perform the test again at a different garage to see what I get.

    Any ideias for this kind of values ? Carbon ?
    Thanks in advance.
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  3. Prawn
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    Prawn My other car is a MINI!!!!

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    [Oct 22, 2007]
    No need to do the test again, those values sound OK to me.

    Compression ratio and dynamic compression are two totally things (i think its dynamic compression the test measures?)

    the figures recorded on a compression test simply indicate the condition of your rings/head gasket/valve seats.

    they are not related to the compression ratio of the engine.

    All those figures seem suitably high, and are within 8psi of each other.

    Id say they were fine!
    #2

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