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Head rebuild

Discussion in 'A3/S3 Forum (8L Chassis)' started by lloydie1, Aug 28, 2012.

  1. lloydie1

    lloydie1 Member

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    So I have an AEB head that's been fully rebuilt with genuine VW parts. Everything! Cost the last owner a small fortune. My question is what fails on the 1.8T head when I hear of failures occurring, and do failures only occur because owners are putting big power through 100k engines? Would an effectively brand new head fare better? If I'm on a budget what should I uprate first? Valves? Retainers? Springs? It will be big turbo when it's finally back together... Ta
     
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  3. <tuffty/>

    <tuffty/> Badger 5 Edition...Its all about the flow...
    Staff Member Moderator Audi S3

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    What turbo are you planning to use?

    The larger the turbo the higher the rev limit needs to be to get the most out of it... generally speaking its the valve guide wear that causes issues... exhausts tend to wear from 60k miles on and the valves will flap about a bit under high rpm...

    lifting the rev range above 7.5k arguably needs uprated springs to prevent bounce... a larger turbo will generally need this but if you do it right then a GT3071r would give you a 3.8k to 7.5k power band but I would still consider doing the valves if you can...

    Some people have just changed the exhaust valves in the past but be aware you need to get the inconel ones as the stainless steel ones are not suitable for turbo engines... if you just change the exhaust valves you will need to get the 3 groove versions (I am talking Supertechs currently) which don't work well with the supertech retainers/springs... these are better suited to single groove valves...

    I am runing a refurb head with single groove supertech valves and springs/titanium retainers on mine but tbh the only stuff that wears out is the guides... providing its not cracked, warped and pressure tests fine then 100k plus head will be fine with new guides...

    <tuffty/>
     
  4. lloydie1

    lloydie1 Member

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    Will be GT28 series. I want better response not so worried about pub figures.
    So you are saying that the fully rebuilt (but actually stock) head i have will be fine at 350-400bhp if i stick to the stock redline ?
     
  5. <tuffty/>

    <tuffty/> Badger 5 Edition...Its all about the flow...
    Staff Member Moderator Audi S3

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    What I am saying is it will stand as good chance as any lol... Welly runs std valves currently but of course its highly subjective to how you drive it and, and... etc... Wellys redline is 7.8k currently but even with a refurbed head setup there will be a degree of risk... you just normally reduce risk of failure with uprated valves/springs...

    To get 400hp out of a 20v then that would normally require revs... stock rev limit is pityfully low in BT terms... a GT28 would still make some power over 7k...

    <tuffty/>
     

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