I bought these Drag Specialties + 0.10 pistons, I can't find any arrows (which usually indicate the exhaust) on the face and the valve seats are the same size.

The only marks I find are those highlighted in the photos.

Who knows them and knows the correct assembly?

 

The cut out goes towards the connecting rod JCC type pistons

but we check them as they are off set wrist pin to the skirt front to the back so they stay in the bore correct at top and bottom dead center and not rock back and forth

 

I didn't understand correctly The cut out goes towards the connecting rod JCC type pistons

I measured from the piston pin bore, front and back and the measurement is the same. The hole is centered
I measured the valve faces on the piston head, and they are the same.
I've mounted the pistons in the cylinders in both directions and the top dead center always stays the same and the pistons don't wobble.

In the absence of arrows and other signs can I say that the pistons do not have a forced direc????


I wrote to JCC in Taiwan for instructions but got no response

The only doubt is this step.

 

The thing you drew the ring around in the above pic, that is what John is referring to when he says " cut out".

 

The cut out in the skirt ( on both pistons) goes towards the "center of the engine" . In other words, both cutouts should face each other when installed.

 

I take it that there is only one cut like this on each piston ? I looked up piston wrist pin offset and found this. Do you have an original piston to compare to.I think you are doing to right thing by looking into this. I would be afraid to use those pistons until I knew.

 

No there are two cuts on each piston, forward and backward

Two cuts, piston crown with equal valve faces, no arrows
The two pistons are the same

The only "sign" is that step...

 

See above about what I saw about offset. I was doing an edit while you responded. Looks like to me that those pistons do not have it. I myself do not see that step.

 

 

To me, that step would point to the side of the piston where the wrist pin goes in and I think that it is not an indicator of installation. It is just the way it is made. I reserve the right to be wrong. lol