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In an automobile engine, the intake manifold controls the air flow and gas mixture that is fed into the piston chambers of the motor. This component usually is found on the top portion of the motor. A proper intake is necessary to produce adequate torque and power.
The intake manifold is responsible for creating an explosive vapor from an air and fuel mixture. This vapor is pushed into the pistons through the intake valves of the heads on the motor. After the vapor fills the cylinder area, it is exploded with the spark from a spark plug, which causes the motor to turn. This process happens very quickly will all cylinders in the motor.
There are many types of intake designs. The type used typically depends on the specifications of motor. A well-designed intake can improve motor performance and overall horsepower because it determines how efficiently the fuel is delivered to the motor.
A high-rise intake manifold is a high-performance manifold often used in drag racing. This manifold provides an air-fuel mixture that creates a smooth response throughout the power band of the motor. High-rise intakes typically are used on large motors with manual carburetor fuel intake systems.
Most modern cars use electronic fuel injection (EFI) to power the motor. A special manifold is required for EFI type automobiles. This manifold is only responsible for adding air into the combustion chamber because the EFI system manages the fuel.
Replacing an intake manifold is a fairly simple process. It first requires the mechanic to remove the carburetor or electronic fuel injection system. This normally sits over the manifold area. Once this is removed, the manifold bolts can be removed, which will make it easy to lift off the motor.
Before replacing any manifold, the old gasket material must be removed from the motor area. This can be accomplished with a putty knife and mineral spirits. This material typically leaves a rough paper edge on the top of the motor when the old manifold is removed. This paper material will cause leaks if not completely removed.
A new intake must be installed with special intake manifold gaskets. These gaskets surround the holes between the manifold and the intake valves on the heads of the motor. The gasket ensures no leaks occur between the intake air fuel mixture and the cylinder heads.
@Melonlity -- good point and a leaking intake gasket is downright annoying and a lot of trouble to fix because removing an intake manifold is a fairly time consuming procedure. You can, by the way, often detect a leaking intake gasket as you will hear a clicking sound under the hood due to air escaping.
But, it's important not to confuse that gasket with another one. A good test is to use water on any suspect gaskets and watch to see if bubble forms when the engine is running. If so, you've got a gasket that needs to be replaced.
That process was a lot easier in the old days when engines weren't so complicated and covered with components. The difficulty of getting to gaskets to even test them underscores the original point -- take the time to do the gasket work right or you will regret it later.
Perhaps the most important part of this process is removing the old gasket completely and replacing it with a reliable one. It might not seem like a complicated thing to do and, really, it's not. However, that is one step you absolutely want to get right or you will regret it.