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Aum engine swop to an agu?

Discussion in 'A3/S3 Forum (8L Chassis)' started by DAZ1985, Dec 20, 2011.

  1. DAZ1985

    DAZ1985 Member

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    Im after some advice about swoping from an AUM engine to an AGU?

    The aum currently fitted to the car has had oil pump failure (or blocked pick up) I'm yet to investigate that part yet

    This has in turn dried the top of oil and caused the exhaust cam to snap under the cam cap between cylinder 3 & 4 theirfore I assume a few bent valves too?

    Basing all this on cost:
    3 new valves
    New cam
    Headgasket
    Bolts
    Oil pump (if it's failed)

    It may work out cheaper drop another engine in. I understand the aum is vvt so I'd need to swop that to the agu head. Is the bare block and head the same? Swop everything over or would it be easier to source an AUM engine and straight swop?

    Thanks in advance
     
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  3. camscockle20vT

    camscockle20vT The stigs ugly brother

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    Im not sure about all your questions but i know the agu head will fit mate.
    Good luck with your troubles, i had this happen(oil pick up bloked) but thankfully sorted it before the engine went boom.
     
  4. beachbuggy

    beachbuggy Well-Known Member

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    If the block is good and the crank not scored or damaged then you could just replace the oil pump and pickup and put the agu head on the engine. Don't worry about swapping over the AUM vvt over just leave it unplugged, you'll get an error if you scan but it won't affect running of the engine. If I where you I would remove the 19mm rods and pistons from the the AUM as well, replace with 20mm rods and pistons , fitting new big end bearings and piston rings.

    I've got 20mm rods and pistons for sale if it helps and you should be able to pick up a agu head pretty easily as well. Be a lot cheaper and easier than an engine swap out.
     
  5. DAZ1985

    DAZ1985 Member

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    That sounds easy enough to do and the most cost effective way too, providing the bottom end isn't scored then I'd probably leave the pistons and rods as they are. It's only a car I've bought to sell on.

    Won't I have any running issues with the aum Ecu not picking up the vvt signal or is it just a case of deleting it out on vagcom?
     
  6. aragorn

    aragorn "Stick a V8 in it!"
    Staff Member Moderator VCDS Map User

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    its trivial to fit the proper VVT actuator if your swapping the head over.

    Personally, i'd just use the complete AGU motor. Given its run for long enough with no oil to sieze the cam, Its entirely likely that the big end shells are toast, and the main bearings wont be far behind.

    The turbo is also potentially wrecked, and TBH its a full rebuild job once the engines got to that stage. Your just giving yourself more work stripping down the replacement engine and trying to swap bits around.
     
  7. DAZ1985

    DAZ1985 Member

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    Agu block and head with aum sensors and vvt bolted too

    I'm easy either way long as I do the job right and it runs after
     
  8. camscockle20vT

    camscockle20vT The stigs ugly brother

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    Is the vvt on these purely for economy or is there any performance upgrade to be had with the vvt?

    Thanks.
     
  9. aragorn

    aragorn "Stick a V8 in it!"
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    Its used to warm the cat up quicker AFAIK.

    Some tuners have seen performance gains, but only when using really large turbos.
     
  10. camscockle20vT

    camscockle20vT The stigs ugly brother

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    So veriable valve timing walms the cat up quicker or better? Im not sure i understand vvt now lol
     
  11. aragorn

    aragorn "Stick a V8 in it!"
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    Audis implementation provides a lot of overlap, which allows a portion of the intake charge (ie the fuel/air mix) to flow streight through into the exhaust. This mixture allows the cat to heat up (and hence start working) faster.

    Other manufacturers use it to provide more power, but Audi hasnt used it that way.
     
  12. DAZ1985

    DAZ1985 Member

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    So would it not cause any issues if it was removed?
     
  13. Lee172

    Lee172 GT3071

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    If i were you id change the whole engine, having just had a similar problem to you and rebuilding my engine i would say it would be easier. I changed to a largeport head and had to change the cam chain tensioner, Camshaft sensor and plate behind it and also the cam pulley as it was different.
     
  14. <tuffty/>

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

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    It will cause a cam setpoint not reached type error and throw a CEL if you don't fit it... there is no reason not to fit it tbh and its a straight forward swap... you can change the tensioner in situe by undoing just the inlet cam you don't even have to release the cam from the chain..

    When you do swap them however make sure you get the 16 rollers in between the cam timing marks set up correctly else you will get incorrect correlation faults appear

    Not sure if the ECU has a fall back (such as not doing adaption) when the VVT is disconnected but I know it can be coded out... that of course is not possible unless you go for a custom map which is much more expensive than generic stage 1 and 2 maps..

    <tuffty/>
     
  15. DAZ1985

    DAZ1985 Member

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    Yeah I get that now, doesn't sound a big job swooping that over for what it's worth

    I'll source an AUM or AGU which ever pops up for the right money locally first

    I just didn't want to jump in and buy an AGU if it couldn't be converted to work with AUM bits an bobs, be an easy enough job to do taking bits off one and fitting to the other

    What do you mean by 16 roller?
     
  16. camscockle20vT

    camscockle20vT The stigs ugly brother

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    Doest this mean if he fits the agu head that he will have better flow around the head comparede to the small port aum? What gains are to be had? Thanks
     
  17. <tuffty/>

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

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    Large port head will flow better yes... arguable gains on a fairly mild setup but a hybrid/big turbo setup the gains are very noticeable...

    Small port heads are used to improve low down drivability which is why VAG fit them

    <tuffty/>
     
  18. beachbuggy

    beachbuggy Well-Known Member

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    Small port increases air flow speed thus better torque but restricts top end bhp which requires good volume flow
    Large port decreases air flow speed thus worse torque but better top end bhp as more air can flow at high rpm. A simplified explation really.



    Same principle as having small twin carbs over large twin carbs.
     
  19. camscockle20vT

    camscockle20vT The stigs ugly brother

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    Sorry for hijaking the thread, but thanks for the replies. So would there be any gains from porting an aum head if thats possible?
     
  20. <tuffty/>

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

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    Typically a porting job is 500-700 quid (ball park)

    AEB/AGU head will flow more and cost you £100 ish on ebay...

    Porting a large port is the ultimate but don't bother unless chasing numbers and using a GT30 or bigger turbo...

    Small ports std or ported don't seem to take as much timing advance as large ports ported or std...

    Save yourself some money on porting a SP head and just buy an AEB/AGU head instead

    <tuffty/>
     
  21. camscockle20vT

    camscockle20vT The stigs ugly brother

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    Yeh im just trying to get my head around whats going to be best value for money, unless i go hybrid ill leave the standard head unless what Iv got warrents a large head 3inc dp and decat(not fitted) silicone tip and cone filter, getting a fmic and doing the catch can and n75. I think thats about it unless i can do the rebuild BB is so kindley showing us all :)
     

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