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I stripped my Forge DV down as i wasnt sure if it was leaking... Advice needed please

Discussion in 'A3/S3 Forum (8L Chassis)' started by S3 Paul, Jan 19, 2013.

  1. <tuffty/>
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    <tuffty/> Badger 5 Edition Staff Member Moderator

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    [Jan 24, 2013]
    The redesigned piston is to fix the leak issue.. seems they have reduced the internal volume a bit too

    There is no need for a stiffer spring as the spring is only used as a return spring not a mechanism for holding it shut... the shim is to reduce the pistons internal volume making it faster to react and the green spring should be all thats needed for the valve to operate normally... this is relevant for the older design but arguably not so much on the new design...

    <tuffty/>
    Last edited: Jan 24, 2013
    #81
  2. s3dave
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    s3dave TFSI Hybrid

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    [Jan 24, 2013]
    Did you see the pics? it has greatly reduced the Volume.... there is no need to shim it trust me...
    #82
  3. <tuffty/>
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    <tuffty/> Badger 5 Edition Staff Member Moderator

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    [Jan 24, 2013]
    I didn't notice but I can see what you mean... use of a shim still stands if using a previous version of the piston though...

    <tuffty/>
    #83
  4. vrbob
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    vrbob Thats no Moon, Thats a space station!

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    [Jan 24, 2013]
    Cool well will see if forge send me the redesigned piston and then I will give it a service put the new piston and swap back to the green spring
    #84
  5. s3dave
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    s3dave TFSI Hybrid

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    [Jan 24, 2013]
    Yeah its almost flush with the spring seat now..
    #85
  6. vanilla_ice
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    vanilla_ice Member

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    [Jan 24, 2013]
    I can see Forge getting a lot of emails about this. vrbob, are you expecting to pay for a new piston?
    #86
  7. <tuffty/>
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    <tuffty/> Badger 5 Edition Staff Member Moderator

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    [Jan 24, 2013]
    Before everyone has a panic.... this...

    <tuffty/>
    #87
  8. vrbob
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    vrbob Thats no Moon, Thats a space station!

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    [Jan 24, 2013]
    If I can then yes that is what would be ideal, There is a link to the service kit which can be found here Forge Motorsport | Alloy Fabrication its £15

    But I am going to see if I can get just the piston FOC as this is the re designed bit and probably the only bit I really need as such
    #88
  9. S3 Paul
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    S3 Paul Well-Known Member Regional Rep

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    [Jan 24, 2013]
    Dave, from the picture it looks like the seal is trapped / secured in place by the end of the piston that looks to be screwed on from the screw head i can see inside?
    #89
  10. vrbob
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    vrbob Thats no Moon, Thats a space station!

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    [Jan 24, 2013]
    Had a reply back from forge saying I could buy the service kit from them :(

    They also say that the new piston design is only for the super size DV, is that right as the pic that S3 Dave posted earlier comparing the new vs old that looks identical to my current piston. so have sent them the pic as an attachment to see if that is correct or not.
    #90
    Vex182 likes this.
  11. <tuffty/>
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    <tuffty/> Badger 5 Edition Staff Member Moderator

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    [Jan 24, 2013]
    Ok... the problem here is that while not ideal the design is not an actual failure... I cannot see Forge replacing every single piston they have ever made because it could potentially leak a little... at least Forge have recognised that the design needs improving and have taken steps to do so...

    Forge valves have been around for donkeys years and while I have no doubt there has been a degree of leakage from some of them over the years its never presented itself as a real world problem... I personally think the whole running too stiff a spring thing is a bigger issue myself... I for one was under the impression the springs rate needed to be higher to hold it shut but I realise now this is not the case and have seen it for myself how much using a lighter spring and reducing piston volume can improve the valves overall performance....

    Lets not forget these parts still wear out over time... a lot of the cases where leaking is an issue are probably just down to wear... this is a soft alloy after all... the wear visible on the side of the OP's piston was from rubber o-rings!... it does happen...

    As I have already mentioned a couple of times the ECU will compensate for small leaks and I very much doubt there is any real world performance hit under normal circumstances (this is too subjective to be definitive of course)...

    The service kits are relatively inexpensive and something that needs to be done once in a while... if you have obvious wear and the grease has mostly gone then all you can really expect from Forge is to make sure the service kit contains the latest revision of the piston...

    <tuffty/>
    #91
  12. s3dave
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    s3dave TFSI Hybrid

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    [Jan 24, 2013]
    Possibly Paul, i didnt bother poking around, im sure it will be fine..
    #92
  13. S3 Paul
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    S3 Paul Well-Known Member Regional Rep

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    [Jan 26, 2013]
    Good news !
    Royal mail managed to finaly find my Package from Forge
    So... i tested the Forge DV as it was... ( sorry no gauge as i had to give the correct pump back ) so i rigged up my cycle pump...

    [​IMG]
    Just to be clear i did locate the clamps correctly before the test was done. i just pushed them on to show what set up i used.



    one pump... Bubbles. as expected, i had lapped the old piston in but either i stopped too soon or ... the Orings had seen better days.
    I stripped the valve down cleaned it completely, Sealed the side port thread ( as this was leaking too on the bubble test ) i used "hondabond" high temp silicone based gasket sealent, when that had cured i rebuilt the valve with the new O rings and piston using the suplied grease as i went...
    Back to the sink to test for bubbles... NONE. as i said i have no gauge to hand today but where the old piston leaked as i finished the first full pump this new set up was holding at three pumps. until the hose i had on the side port blew off.
    In my eyes thats a massive improvement . i retested and left it at two pumps and left it under water... no leaks.
    Everything moves as it should so i know its not stuck but it seals ! thats for sure...

    This is the old piston after i lapped it in... but it leaked far too easy
    [​IMG]

    This is what came in the kit.
    Many thanks to Forge
    [​IMG]
    #93
  14. A3 T
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    A3 T Lord Of The Rings

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    [Jan 27, 2013]
    Well done mate :thumbsup:
    #94
  15. vrbob
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    vrbob Thats no Moon, Thats a space station!

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    [Jan 28, 2013]
    Brucie Bonus :)

    Got an email form Forge this morning to say they are gonna send me out one of the new pistons.

    So once it arrives I will give the 007p a nice service and upgrade the piston. I will also swap my current yellow spring setup to a green spring and a shim and see how this performs :)
    #95
  16. S3 Paul
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    S3 Paul Well-Known Member Regional Rep

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    [Jan 28, 2013]
    I think there is no need for the shim in the new piston. Tuffty mentioned it further up the thread.
    Im running a yellow spring and the car is fine. Now holds bang on whatever boost im at ( say if i put the throttle down and hold it at 10 psi it stays bang on there until i move my foot up or down) it used to drop 3 or 4 psi .
    The "dumping" sound is a crisp "tish" rather than the chatter i was getting.
    #96
  17. badger5
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    badger5 www.badger5.co.uk Site Sponsor

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    [Jan 28, 2013]
    sounds like decent progress
    well done all
    #97
  18. vrbob
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    vrbob Thats no Moon, Thats a space station!

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    [Jan 28, 2013]
    Cheers for the info mate, I have the full spring kit as I bought it off ebay last year. So will stick with the yellow spring and just give it a good service instead when fitting the new piston.
    Last edited: Jan 28, 2013
    #98
  19. Prawn
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    Prawn My other car is a MINI!!!!

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    [Jan 28, 2013]
    Excellent news Paul, Very glad to hear it.

    Now, I must get myself the new piston!
    #99
  20. vrbob
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    vrbob Thats no Moon, Thats a space station!

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    [Jan 29, 2013]
    New piston arrived this morning, Cheers Forge :)

    So as I had an hour spare this afternoon I grabbed my service kit (received last year) and stripped down the 007p.

    Took all the o rings out and gave it a good clean all round removing the old (now black) grease.

    once clean I used the nice pink grease on all the clean o rings and re seated them all.

    Gave the new design piston a light greasing and then re-seated that. Don't over grease it it only needs a very light coating.

    All back together with the yellow spring still in place and did the finger test (push up piston, cover to nipple with finger, release piston, it should drop about 5mm and then hold in that position until you release your finger on the top nipple and it should then snap closed).

    Not done any real world testing but will see how it feels during my commute to work tomorrow.
  21. A3 T
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    A3 T Lord Of The Rings

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    [Jan 29, 2013]
    Swapped my bailey DV30 for the forge 007p and fitted the new style piston today.


    All seems good so far :)
  22. s3clarke
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    s3clarke Money grabbing s3!

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    [Jan 30, 2013]
    Fitted my oem dv the other day, and went for a proper drive yesterday, what a transformation, boost is so much stronger, my forge must have been leaking bad for a long time. oh well I sold it on eBay the other day and I wont miss it lol
  23. vrbob
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    vrbob Thats no Moon, Thats a space station!

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    [Jan 30, 2013]
    New piston seems to work well, didn't get much "testing" done on my way to work (damn those other cars on the road)

    But boost seems good so will maybe do some logging later on.

    So if you have a 007p rather than flog it and buy another get yourself a service kit and ask for the new piston as this may well solve any issues you had and maybe forge will help out FOC if not its only £15 to get it back up and running again. Plus servicing the DV is I good idea too to keep optimum operation.
  24. S3 Paul
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    S3 Paul Well-Known Member Regional Rep

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    [Jan 30, 2013]
    Well thats prety much why i contacted Forge...
    I thought spend on a stock DV to cure the issue ( by removing it ) or see if they could help and to be fair... Yes the DV was pricey when i bought it... but to send me the internals free. Top service and problem solved.
  25. vrbob
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    vrbob Thats no Moon, Thats a space station!

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    [Jan 30, 2013]
    Exactly, I spent near enough £100 on my 007p and spring kit etc so why not get it running correct rather than sell for a loss and buy another DV.
  26. A3 T
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    A3 T Lord Of The Rings

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    [Feb 3, 2013]
    I've got to say this forge valve isn't as loud as my old bailey dv30.

    Not sure if its the new piston or just how these forge valves are?
  27. dre_S3
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    dre_S3 Member

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    [Mar 18, 2013]
    i find my standard Bosch valve is louder then my old 007 the answer I am looking for is how much can the Bosch take ? as I have a brand new 008 DV that I have not fitted, will I need it for when I get my car mapped ? I have sold my 007 by the way and I am using my Bosch at the mo with no problems I find it better the my 007 to tell the truth
  28. Jason.s
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    Jason.s Active Member

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    [Mar 18, 2013]
    30psi has been tested and held fine.
  29. dre_S3
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    dre_S3 Member

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    [Mar 18, 2013]
    So do I really need the 008 for when I get the car tuned ? are the diaphragms in the Bosch strong enough to trust on a tuned s3 ?
  30. dre_S3
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    dre_S3 Member

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    [Mar 18, 2013]
    Double post stupid iPhone :keule:
  31. Jason.s
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    Jason.s Active Member

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    [Mar 18, 2013]
    You dont NEED it no but it`ll outlast the OEM plastic item.
  32. Gops
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    Gops 6th gear @7000rpm

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    [Apr 6, 2013]
    Just thought I'd say, I recieved my forge piston today FOC! They have been great with service! Thumbs up to them! :thumbsup:

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