my wrx has apparantly been bored out and has racing pistons.
there is a noise coming from centre of engine on start up,when warm it goes away. it is making a slap-slap sound.
scooby clinic seem to think this is the racing pistons,but im worried incase something its something else,ie ... big ends or crank, regards simon.

 

Piston slap isn't uncommon with forged pistons.
Edit, I should have added that it's normal for some forged pistons to slap a bit of cold start up and then go quiet when oils up to temp.

 

Simon,

You have a forged engine in your classic now? wow! That really was a bargain then!

 

thanks for that , fingers crossed.
just rang my local subaru garage in highworth ,swindon ,they said to pop it up and they will tell me.cheers simon.

 

As above, forged pistons are known for being a bit "slappy" on start-up. If it goes away when warm, is likely to be that. Bearing noise wouldn't go away, but i'd avise to get it looked at anyway just in case .

Do you have receipts for the build and does it give any indication of what pistons were used Simon?

 

its ok. subaru in highworth "simpsons" at blackworth industrial est have just confirmed that it is piston slap,

 

xspec motorsport did all the work on my scooby, tried to contact them but apparantley graham closed down and his son is now running things "alex" i have been in contact with the new proprieters at mill lane ,they are aware of the scooby and i am waiting for a call back, if anyone has any info regarding xspec motorsports or a new telephone number i wuld be very grateful, regards simon.

 

Mine is really slappy, and I thought it was knocking, but having heard a real knocking engine its a lot different. As long as the engine doesn`t do it when revving or slowing down then your ok.


As I was told get used to the noise, if it does something different start to worry, if it doesn`t chill out. Worth getting an opinion off someone who knows to confirm it so then atleast your mind is at piece.

 

it will be worse in the cold weather and take longer to quieten down, but so long as it does then it's nothing to worry about.

 

Thats true i have noticed it allot more with mine with the cold weather coming back

 

its always annoying
to find your pride and joy is ruined
by someone putting in drop forged pistons and racing bearings etc

 

Yep, what a shame! Poor fella!

 

lol

 

thanks to all for advice.
didnt get any joy from xpsec motor sports, but before i sent the log book off i took down all relevent details,unfortunately couldnt find a tel number so today i took myself off to the previous owners address in leicestershire, as it happens my new scooby use to belong to scoobynet member alspider, and as far as hes aware and his mechanic, who was also there , said that the engine is standard ,no racing pistons or any other mods, but is a genuinly good scooby that his mrs owned for two yrs, result , at least i know. cheers simon.

 

Does that mean that you non forged standard pistons are making a noise that you should be worried about?

 

apparantly not. i took it into subaru dealers yesterday and was checked by their mechanic , he also test drove it and assured me that there are no problems ,also alspiders mechanic assured me no problems.

 

1997~98 engines were prone to a bit of piston slap with the standard Cast WRX pistons - unless its burning oil then its not an immediate problem but bear in mind it wont get any better.

Mick

 

+1, I've known owners to have piston slap for 100k miles with no ill effects other than the noise.

 

Phew! Sorted.

 

thanks for the input and advice chaps.
i was worried, hence taking it to subaru and visiting previous owner. i can start my own project now, had some good advice today from scooby mechanic at alspiders,apparantly had one cat removed,straight through big bore exhaust, induction kit and dump vave.