After drilling a hole in the piston, my engine now revs less.

[Flight Risk]

A&B the more holes the better

OK. I'll work on my Swiss cheese piston soon.

 

[Chainlube]

Believe it or not, there is a way to make a piston work that has a hole in it, no, it's not duct tape.

 

[Gordy]

Believe it or not, there is a way to make a piston work that has a hole in it, no, it's not duct tape.

Jb weld???

 

[Chainlube]

Jb weld???

Not those kind of holes.

 

[Wyvern]

In Nitro model engines, there is such thing as functional holes in pistons- it's called a "bypass"

Basically as the piston comes down, there is a buildup of crankcase pressure, to remedy this, they put holes in the piston head and matching ports in the sleeve, when the piston comes down the cylinder sleeve exposes the holes and air is allowed to escape.