How do valves not fall into piston?

Hi guys,

Just curious as to what stops the valves falling into the Pistons by gravity? I have not serviced tappets or valve seals before so never had a close look at valves. Does the tappet pull them back up somehow?

I have a DX engine so solid tappets btw.

Cheers

The valve springs pull the valves back up. after the camshaft has opened them.

How Car Engines Work | HowStuffWorks

watch the valves and lobes at the top of the animation