What do they mean? What's the difference between two dots and one dot?
The piston with one dot has "63TE8" stamped on the top, the other is blank.
Thanks.

 

what are they off of?
model, year, aftermarket, oem...etc

 

Left looks like a Evo9 piston. The right one is from an Evo8. Good luck with whatever you're doing.

Aaron

 

i dont think any of mine had any dots on them when i took them out.

 

one dot: purchased in the classifieds as evo 8 stock internal.

two dots: came with the car ( 04 RS ) but it's motor was blown & rebuilt in the past...

so no firm knowledge of either of them.

I think the evo 9 vs evo 8 would probably be the best guess. Are there any other markings I should be looking for?

 

The dots point toward the front of the engine. That is what they mean.

 

Just told you what they were from in my first post.

Aaron

 

ttp, but why does one have one dot and the other have two?

 

yeah, i know, thank you. that's why i said it's the best guess. sorry i didn't quote you.

 

I'm pretty sure this is solved. The piston on the left (two dots) has an oil ring that's not an 8 oil ring (i purchased new 8 rings from mitsu). Going by what this guy said - https://www.evolutionm.net/forums/6345461-post13.html it's a 9 piston. So does that mean that all evo 9 pistons have 2 dots?

Are evo 9 pistons that much better? I know they'll fit on the 8 rod, so I'm considering swapping to them.

P.S. WHTEVO -What made you think they were 8 & 9 pistons, like what clued you in?

 

the evo9 has a two piece oil ring vs the 3 piece oil ring of the evo8(if I remember correctly). I would go with the evo9 piston.

 

Yes, that's it. I'll just buy the evo9 oil rings & use my new evo8 1&2 rings on the 9 pistons. Thanks a lot for everyone's help.