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Old 11-04-2003, 09:17 AM   #1
tomoking
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Default piston slap after i changed pistons to arias forfed pistons

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 ??? sorry for my english
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Old 11-04-2003, 11:07 AM   #2
North Ursalia
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You don't want to bore the cylinders to cure piston slap- you need a piston with a longer skirt on it .


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Old 11-04-2003, 11:14 AM   #3
1 Lucky Texan
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Aren't some (all?) Sube pistons marked for orientation due to wrist pin being slightly off center? Maybe that's the older engines but what would happen if he installed them 'upside down'?

Carl
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Old 11-04-2003, 11:54 AM   #4
tomoking
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Quote:
Originally posted by 1 Lucky Texan
Aren't some (all?) Sube pistons marked for orientation due to wrist pin being slightly off center? Maybe that's the older engines but what would happen if he installed them 'upside down'?

Carl
1 Lucky Texan
i have wrx 2002
EJ 20 engine
stock piston have mark for right orientation
arias forged piston do not have mark for right orientation because pin bore is precisely in middle of skirt
arias skirt is longer then stock


Last edited by tomoking; 11-05-2003 at 10:34 AM.
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Old 11-05-2003, 09:28 AM   #5
1 Lucky Texan
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At the very least I think you should get a refund on the new pistons. The reason the stocks have a slightly offset wrist pin is to reduce piston slap! I do agree a longer/different skirt design might do the same. However this all points to the same conclusion. Your new pistons are poorly designed for your application.

Carl
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Old 11-05-2003, 10:36 AM   #6
tomoking
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Quote:
Originally posted by 1 Lucky Texan
At the very least I think you should get a refund on the new pistons. The reason the stocks have a slightly offset wrist pin is to reduce piston slap! I do agree a longer/different skirt design might do the same. However this all points to the same conclusion. Your new pistons are poorly designed for your application.

Carl
1 Lucky Texan
Why ariaspistons.com produced bad pistons for EJ 20 ?

they wrote

ARIAS PISTONS, the leader in sport compact pistons, now offers Subaru WRX piston kits for the EJ20 engine. Forged from high-tensile billet aluminum, ARIAS PISTONS feature fully machined external features for maximum strength and minimum weight. Designed for extreme street or race, turbo or nitrous applications. These shelf-stock kits come complete with 8.5:1 compression ratio .50 mm oversize pistons, case-hardened wrist pins, severe-duty rings and pin locks
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Old 11-05-2003, 12:57 PM   #7
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Well, perhaps they are not poorly designed. Still, they could be undersized or have some other defect.

How long was your engine open during the work? Maybe there is some other source of the noise? TB tensioners can be noisy, lifters,etc. If you engine was inoperable for a while the oil could have gotten gummy or something.

hope you get it sorted out.

Carl
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Old 11-05-2003, 03:28 PM   #8
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tomoking, do a site search here
http://www.northursalia.com/m...ns/index1.html

for engine noise.

good luck

Carl
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Old 11-05-2003, 10:46 PM   #9
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when my friend put those pistons in his honda it sounded loud also. sounded like piston slap but it was due to them being lighter and forged. anyway he had no problem with them.maybe that will help
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Old 11-06-2003, 09:48 AM   #10
Tim Sanderson
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How many miles did you have on your engine when you changed pistons? Did you mic. the bores? Sounds to me like you have too much piston to wall clearance. There should be no more than .004 clearance.

I doubt you would be able to get a refund.
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