There is such thing as too close and too far a gapping...The optimal gapping between the coil and flywheel is .020"....New laserjet business cards are between .010 and .012"
The pebbled finish is slightly better to help with the even ignition and transferrence of the flame kernel across the piston top slowing the flame down towards the cylinder wall keeping the heat away from the rings but collects carbon faster than the smoother topped piston which is the top I prefer because the high compression mixed with the high revs I run these engines at so it doesnt really matter because of the squeeze being so tight the kernel has a very tight-tight area to be bern-in to begin combustion and the added carbon build-up on my pistons would be a problem with the squish I have my engines set at which is considered the danger zone ..Thanks CAMagedon One other quick question for debate.
Piston tops. I've bought pistons that have smooth almost mirror finishes and I've also go ones that are rough like pebbled effect to them. Which is better ? I've heard that a rough top helps with atomisation but wouldn't a smooth top allow for better and accurate compression / squish calculation ?