removed my heads today to change head gaskets.
bores look nicely honed meaning pistons have been out.
but have they been changed. are these standard early pistons?
if not any idea who makes these?


.

 

look standard too me mate
pete

 

thanks pete. only asked because i thought the standard pistons didnt have the raised part in the midle. i know the 96-> had the square sunk into them.

 

As above - they are standard 'dog-bone' pistons.

Mick

 

Is it a bird,is it aplane

 

3 types of 'dog-bone' pistons found on the Version 1~2 :
Cast long skirt
HF Forged long skirt
HF Forged short skirt (RA)

Mick

 

[
3 types of 'dog-bone' pistons found on the Version 1~2 :
Cast long skirt
HF Forged long skirt
HF Forged short skirt (RA)

Mick[/QUOTE]

so is there anyway of telling which mine is? without taking them out.
and thanks for all the help guys

 

so is there anyway of telling which mine is? without taking them out.
and thanks for all the help guys[/quote]


if you take the gudgeon pin bung out of the front of the block you can see the side of the piston if its got cross hatchings its cast and if its smooth its forged, iirc.

 

if you take the gudgeon pin bung out of the front of the block you can see the side of the piston if its got cross hatchings its cast and if its smooth its forged, iirc.[/QUOTE]


The cross hatching of the Cast piston is on the underside of the crown and you might just be able to see it with a torch and mirror through the gudgeon pin access plug.
Forged is as you said -smooth on the underside of the crown and will have HF/1/2/3 stamped on the underside but hidden by the gudgeon pin.

First pic is STI Version 2 RA short skirt HF forged pistons.
Second pic is long skirt Cast dog-bones ( ignore the arrows etc).








Mick

 

The cross hatching of the Cast piston is on the underside of the crown and you might just be able to see it with a torch and mirror through the gudgeon pin access plug.
Forged is as you said -smooth on the underside of the crown and will have HF/1/2/3 stamped on the underside but hidden by the gudgeon pin.

First pic is STI Version 2 RA short skirt HF forged pistons.
Second pic is long skirt Cast dog-bones ( ignore the arrows etc).








Mick[/quote]
Damm how's that for an answer then,never fails to amaze Mick

 

looking at the pic you have just put up. in the center of the piston id dished with 4 circles where the valves fit. mine is raised in the center with the circles on an angle. this is the reason i ask the question in the first place. as i thought the standard pistons had a flat dished center.??? now im confused

 

They are the same piston crowns micky.allen - its just the angle of my first pic and the carbon build up which makes it hard to see.

The only other type of dog-bones are the Legacy ones which have a flat top with deep valve pockets.

Piston design changed on the Version 3 and went to a flat crown with a combustion bowl/dish similar to the pic below






Mick

 

spot on thank you. thats cleared it up for me.

 

No worries

Mick

 

someone once told me that some of these cdb had forged pistons which i didnt think would be true but this would explain the piston slap in my 93 wrx cdb. nice if mine is forged. good info micky.

 

We *heart* Mick when it comes to all things Subaru engine