Controls air intake and exhaust gas out from cylinder in correct time periods.
Intake valve and exhaust valve.
valves are use in four stroke engine, and ports are use in two stroke engine.
Jason
Tappet
Tappet
In a four-stroke engine, the intake valve opens in the intake stroke, allowing air-fuel mixture to enter, while the exhaust valve remains closed. During the compression stroke, both valves stay closed to build pressure. In the power stroke, the fuel ignites, pushing the piston down, with both valves still closed to retain pressure. Finally, in the exhaust stroke, the exhaust valve opens, allowing gases to escape, while the intake valve stays shut. This cycle repeats continuously, ensuring efficient engine operation.
Explain the advantages of four-stroke engine over two-stroke engine
What is the Mercury 3.5 Hp four stroke valve clearance?
in my opinion a two stroke engine is a better quality engine as compared to a four stroke engine!
two stroke
On an overhead cam engine, the lobes on the cam push the rocker arms which push the valves open.
Some two stroke engines have 4 valves, Detroit Diesel 71 series and 53 series engines for example. Most small 2 stroke engines have no "Valves" at all in the sense of the "POP" valve used in four stroke engines. Some people feel these engine has one valve because the piston acts as the valve covering the ports cut into the cylinder walls.