Q:

What is valve overlap?

A:

Quick Answer

Valve overlap is the period during the valve timing where both the intake and exhaust valves are open. Occurring towards the end of the exhaust stroke, the intake valves are opened just before all the exhaust gases are released, providing more time for the intake air to enter the engine.

Continue Reading
What is valve overlap?
Credit: Getty Images North America Getty Images Sport Getty Images

Full Answer

Valve overlap is necessary because as the engine rotates faster, the amount of time spent in the intake stroke decreases. This means the intake valve has to open sooner to give time for the intake air to accelerate and flow into the cylinders. It is because of this that fixed camshaft profiles, which control valve timing, are only perfect at a certain engine speed. Variable valve timing was invented to solve this problem and help produce the maximum amount of performance possible at all engine speeds.

Learn more about Engine

Related Questions

  • Q:

    What are some different Chevy 283 engine modifications?

    A:

    Common modifications to increase the power of the Chevrolet 283 cubic-inch engine include increasing the engine's crankshaft stroke, porting and polishing its cylinder heads, and modifying the air intake and exhaust systems. Adjusting the compression ratio of the 283 engine is also a good way to increase power output, as most Chevrolet small-block V-8 engines have considerable leeway for increasing compression ratios over the factory standard without risking damage to the engine.

    Full Answer >
    Filed Under:
  • Q:

    What are some tips for troubleshooting a Ford F350 engine?

    A:

    When troubleshooting a Ford F350 engine, check for evidence of common problems experienced by Ford F350 owners, such as a poorly programmed diesel particular filter cleaning cycle, a failed high pressure oil pump and white smoke exhaust. Check the hose between the turbocharger and intake manifold for consistent pressure.

    Full Answer >
    Filed Under:
  • Q:

    What are some cheap ways to boost horsepower in a truck?

    A:

    Cheap ways to boost horsepower in a truck include getting a tune-up, installing a cold-air intake, getting rid of extra weight and installing an aftermarket exhaust system. One of the more expensive measures a driver can take includes investing in an engine tuner.

    Full Answer >
    Filed Under:
  • Q:

    How is piston ring failure best recognized?

    A:

    Some of the most common ways to recognize piston ring failure include excessive oil consumption by the vehicle, noticeably low power during acceleration and excessive amounts of white or grey smoke emanating from the exhaust. As the piston rings control and regulate oil pressure and consumption, an overall loss of power and generally less capable performance may also indicate a piston ring issue.

    Full Answer >
    Filed Under:

Explore