Hi guys!
Is anyone can tell me the difference beetween a RH piston and LH piston (EJ20G Legacy turbo 1996). I have both in my hands and I took several mesurments to see if there's any differences. Both piston seems to be the same size, except that there's a letter L (left) and R (right) marked on the top of the piston. There's also an arrow that tells witch way to install the piston. The direction of the arrow should point to the timing belt. I know that the hole for the retaining pin is offset, but if it's the same offset one on both!
Thanks!
Francois

 

Ive never seen on of the pistons so probably talking lots of waffle but here goes
The main reason is probably if its a screw thread then the tread on the LHS one is opposite to the thread on the RHS one (ie reversed so one goes anti clockwise and the other clockwise) or it could be that the mounting has a notch of some sort?

Tony

 

Hmmmm, bolt on pistons

I suspect that it's due to the early dish design. The relief is different for the exhaust/inlet valves.

On the later engines (certainly 97/98) the dish is square, and the only thing you have to worry about, is the arrow, or dot, which makes sure the offset pin is positioned correctly.

Mark.

 

Thanks for your anwsers!
Is there any danger to install a RH piston on the LH side? If the arrow point on the opposite direction (flip 180 degree), the offset and the dish desing will be will be ok. I'm a right?
Francois

 

On earlier engines, the L+R I think refers to the fact that the cut outs for either inlet/exhaust are bigger. The inlet valve is bigger, therefore the cutout in the piston is bigger for the inlet valve. The pistons have to be sided L+R, so that the inlet cutouts are always at the top. If you put a left piston into the right side, the inlet cutouts will be at the bottom.
Im not 100% certain about it, as its been a while since I had a legacy engine apart, but im pretty sure thats the reason.
If you use newer pistons, with the square cutout/dish , then no need to worry, just make sure the dot is at the front.

 

yeah, as above, reason for left/right is valve cut-out size.

so they must be on the correct sides.

ian