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pistons rods and shells

Discussion in 'A3/S3 Forum (8L Chassis)' started by stevegti2, Apr 30, 2013.

  1. stevegti2
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    stevegti2 Member

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    [Apr 30, 2013]
    hi all about to rebuild a spare engine i have just a couple of questions for the people who have experiance with these blocks


    1. are vw mains and big end bearings good at higher horsepower or should i use acls

    2. wossner pistons alot of slap ? ive never used them but seems to be alot of them out there with P.E.C rods


    any info on parts youve used is appreciated only other engines ive build have used cp pistons and pauter rods but im not a milionaire anymore lol



    thanks
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  3. 16Klappe
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    16Klappe RacecaR forward is RacecaR backwards. Supporter

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    [Apr 30, 2013]
    Why upgrade pistons?
    #2
  4. <tuffty/>
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    <tuffty/> Badger 5 Edition Staff Member Moderator

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    [Apr 30, 2013]
    I run OE shells on mine with no issues... calico are the only others I would use...

    If not doing a rebore then stick to OE pistons and fit new rings and hone bores... if going for a rebore then buy JE's...

    <tuffty/>
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  5. IrishDave
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    IrishDave Active Member

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    [Apr 30, 2013]
    Tuffty. For the main bearing would you use thrust washers or not. To be honest I don't even know what they are.
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  6. <tuffty/>
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    <tuffty/> Badger 5 Edition Staff Member Moderator

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    [Apr 30, 2013]
    Erm... think its a given you would use thrust washers... not sure what you are asking?

    <tuffty/>
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  7. stevegti2
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    stevegti2 Member

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    [Apr 30, 2013]
    pistons because if im doing a job may aswell do it properly hopefully engine will be close to 400bhp near the end of the year plus nice fresh bores more ccs less compression many benifits even if there not needed for the power

    stock shells should work fine then :)

    tuffty je pistons are the only ones i was trying to avoid they work really well but every engine ive seen with them has slap on start up i know there cheap and cheerful mind
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  8. superkarl
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    superkarl MAN OF STEEL

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    [Apr 30, 2013]
    Slap just means too big piston-wall clearance. So theyve either bored too big or specd the wrong size pistons.

    Think about it, how can one 81mm piston have slap compared to another 81mm piston in the same bore.

    imo theres no point in pistons unless youre boring out/stroker, or your current ones are damaged.
    You cant go higher comp than you already are anyway so theres another reason not to.
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  9. <tuffty/>
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    <tuffty/> Badger 5 Edition Staff Member Moderator

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    [May 1, 2013]
    JE's aren't cheap and cheerful mate... no idea where you got that from and as Karl has said, if you get slap then its not been machined right...

    <tuffty/>
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  10. stevegti2
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    stevegti2 Member

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    [May 1, 2013]
    i know why they slap just my experiance with them the machine shop only bores the block to the manufacturers specs ie je cp pistons seem to have a tighter clearance and never slap and are proven in performance from what ive seen the jes expand more than some other pistons

    and im pretty sure that je are one of the cheaper pistons out there ....they work im just not a fan

    karl expansion rates piston shape and material all differ in pistons thats how they differ

    not being able to go higher comp is a reason not too :/?? i want less compression not more and yes i am overboring
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  11. IrishDave
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    IrishDave Active Member

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    [May 1, 2013]
    why could you not raise comp and increase the bore. surely you would not want to lower the comp ratio as this would hinder performance. I plan to run 83mm pistons with a 9.5:1 comp ratio.
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  12. superkarl
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    superkarl MAN OF STEEL

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    [May 1, 2013]
    Sounds like he really knows what hes doing.
    Leave him to it
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  13. IrishDave
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    IrishDave Active Member

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    [May 1, 2013]
    Actually I was questioning your first comment Karl. Lol. imo theres no point in pistons unless youre boring out/stroker, or your current ones are damaged.
    You cant go higher comp than you already are anyway so theres another reason not to.
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  14. <tuffty/>
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    <tuffty/> Badger 5 Edition Staff Member Moderator

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    [May 1, 2013]
    From what I understand JE's typically use a 2618 alloy which does expand more but but has better tensile strength than 4032 alloy... the specs suggest 0.500" and other sources suggest .004" typical plus .100" if a blown engine due to higher cylinder temps....

    4032 is a harder material so will use tighter tolerances... the 'alledged' flip side is they are less tolerant to detonation etc but in reality still a better material than most OE pistons...

    Not done loads of reading up on this yet as I an currently not in the market for pistons but for most street level tunes you could argue a piston made from 4032 is more suitable but for a track/strip orientated build then 2618 based pistons would be a better choice...

    <tuffty/>
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  15. superkarl
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    superkarl MAN OF STEEL

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    [May 1, 2013]
    his current pistons are 9.5:1, im not aware of any 10s out there. But sounds like hes lowering it anyway for some unknown reason. Good luck to him

    Sounds to me like hes read far too much on vortex. Where people have 800+hp drag cars runninh 67mm inducer turbos and piston material might matter.
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  16. IrishDave
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    IrishDave Active Member

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    [May 1, 2013]
    ^^ Got ye. As my current comp is 9.0:1 I will defo be raising it. It does seem rather foolish to lower it unless running big power from an equally big turbo.
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  17. superkarl
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    superkarl MAN OF STEEL

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    [May 1, 2013]
    Ive raised mine to 9.5. So has tuffty.
    I think lower comp only really applies to BIG boosting high power cars. Im talking 3 bar+ drag cars.
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  18. badger5
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    badger5 www.badger5.co.uk Site Sponsor

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    [May 1, 2013]
    Not when bored to correct clearance.

    JE not cheap and chearful.. Wossner etc.... they are cheaper
    #17
  19. badger5
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    badger5 www.badger5.co.uk Site Sponsor

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    [May 1, 2013]
    mines 9.5:1 CR on badgerwagen now
    previously 8.5:1 CR
    #18
  20. Broken Byzan
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    Broken Byzan Photographic Moderator Staff Member Moderator VCDS Map User

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    [May 1, 2013]
    No slap on my Wossners @ 9,25:1
    #19
  21. stevegti2
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    stevegti2 Member

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    [May 1, 2013]
    hit the nail on the head with that descrption tuffty thanks i never said there a bad piston they all perform well ive just noticed they slap a bit from cold start up in my experiance

    thankyou bill i was told wossners were alright ive seen a few engines with them none with that much power mind

    i idealy wanted a 9.0-1 cr i like a bit of lee way 9.5 would be better for sure but its only gonna be run on pump fuel its not a all out race car
    #20

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