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Combustion Gases in Water Jacket

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    Combustion Gases in Water Jacket

    Gentlemen,
    I have an interesting problem. My brother bought a 318i with a bad motor (broken cam, longer story). 4th M42 in family. Proceeded to have a different head rebuilt but decided not to have pressure checked as it came off a known good engine. Used new gaskets, bolts, etc, bolted it all together and had compression gases in cooling system. Torn it back down and found what we thought was a spot of sealant from the profile gasket area on the cylinder head gasket that I must have transferred there when I handled the head gasket with gloves on. The machine shop and I concluded that this was probably allowing combustion gases to pass by the gasket. Just to make sure I had the head pressure checked and it passed. Made sure I did not repeat the error, cleaned everything, bolted it back together a second time with the same results. So now the guessing games begin (at least for me, unless one of you can shed more light on this).
    Next steps:
    Call machine shop (which has done other M42 heads for me) and ask what pressure they check the head at
    Questions:
    • Could there be an undetected high pressure only crack in the head and has anyone ever seen this on an M42 head?
    • What is the probability that the issue is that the head gasket has just not seated and has anyone ever had this issue with an M42?
    • As a test if #2 is probable (and since the head may have to come off again anyway) what is the advisability of taking a few extra degrees of rotation on the stretch head bolts to try to get the gasket to seat? If a good idea, how much?

    Thanks
    David Beagle
    Seattle
    Ex Pro 3 and Chump Driver/Car Builder/Owner
    1991 318is Track Car
    ND Maita - Daily Driver
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