[QUOTE="zymurgy"] AOL. Tappets comes from the OHV days, where the rocker arm was adjusted against the valve, The tapping was what you could hear when you rocked the rocker arm. Sadly, all that's long gone with OHC and hydraulic 'tappets'[/QUOTE] Admittedly modern engines are a lot quieter but Ford OHC engines had separate rockers and tappets that required adjustment and the Jaguar XK engine manual refers to the bucket over the valve as the tappet. Fig 61: [URL]http://sweller.dynalias.org/docs/JagTappets.pdf[/URL]