multivalve
adjective
mul·ti·valve
| \ ˌməl-tē-ˈvalv
, -ˌtī-\
, -ˌtī-\
Definition of multivalve
: having or involving multiple valves
multivalve heart disease
specifically, of an automotive engine
: having more than two valves in each cylinder
Older engines had only two valves per cylinder, so there was plenty of room for a nice, fat spark plug to stick its nose into the cylinder. But the majority of engines today are multivalve. You could have four or five valves cut into the top of each cylinder now, leaving much less room to fit a plug there. — Tom Magliozzi