A pent-roof combustion chamber features two angled planes meeting at a central ridge, resembling a shallow gable roof. This geometry is standard in overhead-cam, multi-valve engines because it accommodates four valves per cylinder and positions the spark plug dead center. The design promotes excellent flame propagation and rapid exhaust scavenging.
Heard on the job
The new head casting uses a pent-roof chamber to fit the larger intake valves and improve the squish area.
Also heard as
- penta engine
Related terms
Cylinder head
This cast metal component bolts to the top of the engine block to seal the combustion chambers.
Overhead cam
A valvetrain layout where the camshaft is located in the cylinder head above the combustion chamber.
Intake valve
A mechanical valve in the cylinder head that opens to allow air into the combustion chamber.