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Engine damage

Discussion in 'A3/S3 Forum (8L Chassis)' started by Scullies, Jul 3, 2013.

  1. Scullies

    Scullies Well-Known Member

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    My mates TT 225 has died. So been helping him investigate the cause. Compression test showed cylinder 3 with a low compression.
    So we pulled the head off in hope that it was an issue with the valves. But not such luck.
    Found cylinder 2 & 3 to have some damage to the pistons. All the pistons have evidence of contact with the valves but I think this happen before he bought the TT, as he has an invoice for some work done to the head and there is no damage to the valves now.

    The pcv system is also poked, as there is a lot of oil in the intake system and throttle body is pretty dirty.

    There were some random bits of metal inside the cylinder that has been beaten around with the 3rd cylinder taking the most damage.
    Anyone have any ideas of what's happened?
     

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  3. superkarl

    superkarl MAN OF STEEL

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    The top of cylinder 3 looks like a milder version of mine. Ive since found my sparkplug destroyed and have now come to the conclusion that the ceramic broke up, smashing around the bore causing detonation.


    Its a bit of a stab in the dark finding out what causes these things
     
  4. beachbuggy

    beachbuggy Well-Known Member

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    That's had a cam belt failure at some stage and dented the pistons..
     
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  5. S3quatt

    S3quatt Flat Oot like a ducks Foot
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    My thoughts straight away. Looks like valve impacts.
    How do the bores look?
    Scored at all?
     
  6. s3dave

    s3dave TFSI Hybrid
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    Looks like they never bothered to flatten and polish the collision marks and so caused further detonation/hotspots..
     
  7. Scullies

    Scullies Well-Known Member

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    Yeah,definitely had some love from the valves. Head and valves are ok, them BAM marking has been filed off so I am assuming someone did a quick fix with another 20v head and bolted it on then sold the car on.
    cyl 3 has some scoring nothing serious but will need a rebore and some 82mm pistons.

    TT owner has decided it needs a rebuild with some rods and a stage 2 with wmi. Maybe a k04 hybrid later down the road, I will have to keep working his rubber arm :)
     
  8. S3quatt

    S3quatt Flat Oot like a ducks Foot
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    Win Win then!
     

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