Machining the sparkplughole and counter bore at a compound Angle.
加工火花塞孔与反孔的复合角度。
2
The most common "hole" in a cylinder occurs where the top of the cylinder (holding the valves and sparkplug and also known as the cylinder head) attaches to the cylinder itself.
气缸上的孔最可能出现在气缸顶部（装阀门和火花塞的部位也即气缸盖）。
3
As the piston moves up it is compressed, the sparkplug ignites combustion, and exhaust exits through another hole in the cylinder.