Cylinder Heads

Cylinder Heads

The new 911 Turbo features completely new cylinder heads compared with the previous models. The camshafts are no longer located in separate camshaft housings, but are completely integrated in the new cylinder heads. This reduces the number of components, sealing faces and screw connections, resulting in a more compact construction and reduced overall weight.

The improved cross-flow cooling enables good cooling of the cylinder head, in particular the areas subjected to high thermal loads around the exhaust valve-seat rings. The intake ports have a special shape to support efficient mixing of the air and fuel. The tumble port used in the 911 Turbo for the first time is characterized by narrowing of the intake ports upstream of the valve seat. This port form accelerates the air flowing into the cylinder and sets it in a tumbling motion, allowing the injected fuel to mix even better with the intake air.







To ensure the excellent sealing quality of the surface of the multi-layer steel gasket, the gasket is covered with high temperature-resistant plastic. The advantage of this steel gasket is that the heat can be conducted very well away from the cylinder head.







Cylinder Head Cover







The cylinder-head cover is a separate part made of light-alloy. To ensure excellent sealing, a rubber gasket is used between the cylinder head and cylinder head cover.

Camshafts







The camshafts are supported in the cylinder head by means of bearing saddles. To avoid confusion, the bearing saddles are stamped with the matching numbers and the letters "E" for intake and "A" for exhaust.

The timing is as follows:

Intake opens, large lift 17.6° after TDC
Intake closes, large lift 55.3° after BDC
Intake opens, small lift 38.5° after TDC
Intake closes, small lift 18.7° before BDC
Exhaust opens 38.3° before TDC
Exhaust closes 6.3° before TDC