CONSTRUCTION
The cylinder head structure is simplified by separating the cam journal portion (camshaft housing sub-assembly) from the cylinder head.
The cylinder head, which is made of aluminum, contains pentroof-type combustion chambers. The spark plug is located in the center of the combustion chamber in order to improve the engine's anti-knock performance.
A taper squish combustion chamber is used to improve anti-knock performance and intake efficiency. In addition, engine performance and fuel economy are improved.
The port configuration is an efficient cross-flow type in which the intake ports face the inside of the V bank and the exhaust ports face the outside.
The intake ports for each intake valve are independent, and feature a narrow-diameter construction. The exhaust ports have a siamese construction to enhance low- to medium-speed torque.
Upright intake ports are used to improve the intake efficiency.
| *1 | Intake Valve | *2 | Spark Plug Hole |
| *3 | Exhaust Valve | *4 | Camshaft Housing Sub-assembly |
| *a | Bottom Side View | *b | A - A Cross Section |
| *c | Taper Squish Area | - | - |
|
Intake Port | |
Exhaust Port |
Tech Tips
The difference between an independent type intake port and a siamese type one is shown in the illustration.
| *A | Independent Type | *B | Siamese Type |
|
Intake Port | - | - |