pistons slap after i changed pistons to arias forged
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This is a discussion on pistons slap after i changed pistons to arias forged within the General Maintenance, Troubleshooting & Accidents. forums, part of the Tech & Modifying & General Repairs category; My engine has piston slap after i changed pistons to arias forged pistons. I can hear slap when engine is ...

  1. #1
    Registered User tomoking's Avatar
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    pistons slap after i changed pistons to arias forged

    My engine has piston slap after i changed pistons to arias forged pistons. I can hear slap when engine is cold and when is hot . What i have to do for repair slap ??? should i bore/hone the cylinders to bigger diameter or opisit i should get oversized pistons ???
    WRX 2002, IHI VF 34, FMIC, ...........

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    Banned dark_rex's Avatar
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    while the boxer engine is prone to piston slap in warm up conditions, it should be inaudible when the engine is warm.

    type c has done extensive research here. i would PM him for more info.

    dR

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    Registered User WRXJIM's Avatar
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    keep in mind forgies make more noise than standard pistons too...
    * 1:18.47 Manfield * 11.81 @ 114.7mph *
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    Registered User tomoking's Avatar
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    Originally posted by WRXJIM
    keep in mind forgies make more noise than standard pistons too...
    cold and warm engine sound like diesel engine ... Can piston slap kill my engine ???
    WRX 2002, IHI VF 34, FMIC, ...........

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    Registered User WRXJIM's Avatar
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    Worse when cold... Bit you can hear the knock... Not enough of a knock to make you cringe... (if that makes sense)
    Is your engine rocking/shaking/labouring?
    How many miles do you have on it/pistons?
    If it is alot worse than when you first got it back from the engine builder I would go and see someone.

    YES piston slap is bad, but as I said forgies are usually louder than standard pistons... It will wear your bore and wreck the skirts on your piston. It is actually fairly common on Subarus. Gravity dragging the piston downwards...

    Its a tough one to guage without hearing it...
    * 1:18.47 Manfield * 11.81 @ 114.7mph *
    ----
    Tuned by
    SPEEDTECH
    ----
    PICS<---->VIDS

  7. #6
    Registered User PlatinumWRX's Avatar
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    Rob's fully forged internals were very noisy, more so when cold. As long as you got the bore within spec, it should be fine.

    Piston slap makes baby Jesus cry.

    -Jim

  8. #7
    Registered User tomoking's Avatar
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    Originally posted by WRXJIM
    Worse when cold... Bit you can hear the knock... Not enough of a knock to make you cringe... (if that makes sense)
    Is your engine rocking/shaking/labouring? ........no
    How many miles do you have on it/pistons?.......800
    If it is alot worse than when you first got it back from the engine builder I would go and see someone.

    YES piston slap is bad, but as I said forgies are usually louder than standard pistons... It will wear your bore and wreck the skirts on your piston. It is actually fairly common on Subarus. Gravity dragging the piston downwards...

    Its a tough one to guage without hearing it...
    WRX 2002, IHI VF 34, FMIC, ...........

  9. #8
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    Running forgies(4thou ) for 2yrs now and engine is noisy.
    Forgies expand when hot and clearance is greater than OE pistons in order to run more boost.
    U ll probably have some oil consumption.Nothing to worry.


    Cheers

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    Exclamation I have had this problem 2!

    i have had this problem and am working to a resolution atm. i would strongly recomend to anyone who is haveing this problem just after a rebulid not to drive or run the car. i have done aprox 800km and pulled the heads off and found scraches in the bore starting about 2-3 cm down the bore and continuing to the bottom. on oposte sides if the wrist pin. i used arias pistons. i have removed them and am mesureing them atm. its simply just not worth the risk. to see my progress on the issue please visit

    forums.nasioc.com/forums/showthread.php?p=25856247#post25856247

    I hope this helps Paul

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