I am getting ready to rebuild my CV Hyper as a back up motor in my XXX-NT. I pulled it apart last night but can't remember where the hole in the side of the piston goes. Does it go on the exhaust side? or on the closed off side?

Also I am currently using a OS TR 12, it seems to run well, but after only a few runs the plug goes bad, I have been running #8s in everything, but they keep burning up. I tried an A5 that came with the motor and it seemed to work fine. Is my tuning off or is it possible I just need to use an A5 plug.

My #8s still light up all except the top coil which is a greyish color, but when using these plugs as soon as I pull the igniter off the engine dies at idle.

Sorry if these questions sound dumb, I've been racing for 15 years but this is my first gas experience, I've been holding out, but since electric offroad is kinda dead in my area I figured I'd give nitro a shot.