Back in the day, a car's intake and exhaust valves opened a specific amount at a specific point in the four stroke cycle, and for a specific amount of time. It was that simple. Nowadays ...

Using the compressed air/water method, you will actually be able to see bubbles forming past a bent valve on the intake or exhaust side—the larger the leak, the bigger the bubbles. If your ...

At the very end of the exhaust stroke, when the exhaust valve is still closing, the intake valve will start opening. The opening intake valve brings in a torrent of fresh air that helps expel the ...

The Crane solid-roller bumpstick in our Chevy 406 (see "Mean Mouse: Chevy 406" for the engine build) called for 0.020 inch of clearance (on a hot engine) on both the intake and exhaust valves.

Intake valves open and close to let the air-fuel mixture (or just air in some modern engines) enter the cylinders, and the exhaust valves allow exhaust gases to escape. Too much or too little ...

As a vehicle's engine operates, the intake and exhaust valves open and close rapidly while the pistons move up and down in the cylinder. These mechanical actions require a constant supply of hot oil ...

Our simple trick that anyone can do is to add a 30-degree back cut to the inside diameter of the 45-degree seat angle on an intake and/or exhaust valve as a way to improve flow. We talked with ...

There is also no need for a minimum of two valves (intake and exhaust) per cylinder as seen in a piston engine. Instead, fuel enters via intake ports that don't need to open and close. In a Wankel ...

The whole build began with an idea for a different kind of intake and exhaust valve. [Meanwhile In the Garage] dreamed up a design that does away with the traditional poppet valve. Instead of ...