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  • 3b cylinder head

    Hi there. Got my cylinder head off.
    It has one crack trough spar plug hole and pitting. Please advice is it worth repairing?
    can it be repaired? Or is scrap? Just needed a bit of information from experienceed forum members.
    if it's repairable please recomend me a place or a person so I can at least send it for inspection.
    LukasR

  • #2
    Just been reading up on engine overhaul link posted here on another thread today.
    http://s2-audi.co.uk/workshop/aan/aan.pdf
    There is a section on cracks and what is acceptable for continued service.
    Zoomed in on your pic and doesn't look too bad in the pic. I think the tolerance was 1mm and no further than first thread of spark plug threads. Suggest you have a read.
    Looks like something else has been bouncing around in there as well? Turbo exploded?
    S2 Avant in restoration
    S3 Sportback daily
    Terrecan parts collector

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    • #3
      Just checked again and it's 0.5mm
      S2 Avant in restoration
      S3 Sportback daily
      Terrecan parts collector

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      • #4
        Looking at The other damages i would say it's scrap but worth to ask experts

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        • #5
          Looks like the head hasn’t been skimmed yet, so the other “defects” will get skimmed and all good. Even without skimming don’t know how they can affect something?

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          • #6
            Before you throw it away if you think it's scrap send it to me and I ll weld it and skim it and if you want to try it and it works pay for the work I ve done if it doesn't use it for a paper weight . I ve done a fair few of overskimmed race engines by welding and reskimming them and there still going.

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            • #7
              You have had some particles jumping between your head and pistons, but no worry, those marks on the squish are doesn't do anything when the head is skimmed. Just put it back and drive it hard.

              Audi UrS4 Avant 2.5 20vt - twincharged - Project
              Audi 80q B4 Sedan 2.2 20vt - Daily user
              BMW 320d Touring e91 M-Sport - Daily user
              BMW 740iA e38 - Project

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              • #8
                I’ve seen a lot worse, biggest concern is hot spots over heating and causing knock. As above, dress it back and weld the low spots. You’ll be fine once it’s faced off. It’s a common repair, especially on heads off race engines with a lot of time (money) invested in them. We do a lot of repairs like this on air cooled Porsche heads as they are hard to find and very expensive. Crack sounds borderline, I’d roll the dice and run it. 99% off S2 heads are cracked, some worse than others
                Panthero Coupé quattro 20vt
                Indigo ABY coupé
                Imola B6 S4 Avant

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                • #9
                  Has anyone actually experienced an engine failure as a result of cracks between the valve seats and spark plug threads? Material cracked off or pressure leakage? Nearly all of the heads I've seen have them and everyone panics about them, but do they really cause any issues/failures???
                  91 Modded 3B
                  14 A6 Avant Black Edition

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                  • #10
                    I’ve got a theory the cracks to the plug threads can cause the plugs to come loose, as they heat cycle. Just a theory
                    Panthero Coupé quattro 20vt
                    Indigo ABY coupé
                    Imola B6 S4 Avant

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                    • #11
                      Hi there, sorry for late respond, been very busy at work, head is getting sent to machinist. Together with block, crank and flywheel.
                      will post some pictures as soon as is back.
                      thanks for advice.
                      I'll probably go for full rebuilt, any one got any feedback on ferrera valves? worth going oversize? or standard is ok?

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