The "bumps" you refer to are called the "lobes". They are a precise size that allows the valves to open and close correctly in an engine.
DOHC. Obviously a v-6 or v-8. DOHC- Double OverHead Camshafts. 2 camshafts per cylinder head.
Bumps
These bumps are called nodules
the bumps on the moon are called craters which has happened by comets and other objects.
The red bumps on a turkey's head are called CARUNCLES.
They are called milk glands(bumps) prepares baby's milk
Warts
They are called manarilose
osteoderms
The bumps on our skin are called goose bumps as they resemble the bumpy skin of a goose after it has been plucked.
The little bumps are called moguls.