Piston Broke
Posted: Sun May 04, 2008 7:25 pm
Hi guys, first contact on this sensational site. I have a 97 2 litre Impreza five speed, single overhead cam. Has a wicked piston slap noise left side front piston. A common problem I believe. It sound like a dude inside the motor with a big hammer going for his life.
After a bit of research I have found that the piston design which has a short skirt introduced by Subaru for better effeciency, tends to rock a bit in the bore. Eventually turning into piston slap. When the piston reaches its expanded size, the clearences are taken up and hence the noise goes.
The noise is only when cold, once warm, (that is:- after being driven type warm) the noise diappears.
Anyhows, Options: Rebuild orginal motor. or find a rebuildable double overhead cam.
Problem experienced, Trying to find resonably priced oversize pistons for the motor is becoming difficult. I had one place quoting me $1000 for a set of pistons,
no machining.... just the pistons OMG!!!
I went to Parramatta Subaru and you wouldnt believe it, the pistons are a discontinued part. Again..... OMG!!!
Can someone out there me with a source from whom I can get oversize pistons from, for a decent price that is.
I live in Sydney, dont mind having the pistons sent to me, as long as I get the right ones.
I believe that Cosworth make a piston with an offset gudgeon pin which helps elleviate the problem.
Apart from that, the Subi is sensational. Love the power and drive-a-bility.
WRX's must fly.
I know, I am hearing all the subi buffs out there saying, put a REX motor in the Impreza, bit I cant and wont as my some is only 16 y.o and he dont need that much grunt just yet.
Anyway, sorry for the long winded thread, but people... I do like to chat
Take care VL BENNY
After a bit of research I have found that the piston design which has a short skirt introduced by Subaru for better effeciency, tends to rock a bit in the bore. Eventually turning into piston slap. When the piston reaches its expanded size, the clearences are taken up and hence the noise goes.
The noise is only when cold, once warm, (that is:- after being driven type warm) the noise diappears.
Anyhows, Options: Rebuild orginal motor. or find a rebuildable double overhead cam.
Problem experienced, Trying to find resonably priced oversize pistons for the motor is becoming difficult. I had one place quoting me $1000 for a set of pistons,

I went to Parramatta Subaru and you wouldnt believe it, the pistons are a discontinued part. Again..... OMG!!!
Can someone out there me with a source from whom I can get oversize pistons from, for a decent price that is.
I live in Sydney, dont mind having the pistons sent to me, as long as I get the right ones.
I believe that Cosworth make a piston with an offset gudgeon pin which helps elleviate the problem.
Apart from that, the Subi is sensational. Love the power and drive-a-bility.
WRX's must fly.
I know, I am hearing all the subi buffs out there saying, put a REX motor in the Impreza, bit I cant and wont as my some is only 16 y.o and he dont need that much grunt just yet.
Anyway, sorry for the long winded thread, but people... I do like to chat
Take care VL BENNY
