Manifold & exhaust systems (Exhaust manifold): Description and operation

EXHAUST MANIFOLD

’K’ Series Engine

The exhaust manifold is a fabricated and welded steel construction. The four branch manifold is located on five studs in the cylinder head and secured with five nuts. A metal corrugated gasket seals the exhaust manifold to the cylinder head. The four separate branches of the manifold merge into one at a siamesed flange. The flange is fitted with four studs which mate with the exhaust system front pipe and sealed with a metal gasket.

A Heated Oxygen Sensor (HO2S) is fitted in the flange and faces the engine block. The HO2S measures the oxygen content of the exhaust gases at the point where the four branches merge.

’L’ Series Engine

The exhaust manifold is made from cast iron. The manifold has three separate branches, the centre branch being shared between No’s. 2 and 3 cylinders. The manifold is attached to the cylinder head with four nuts and two bolts which also retain the inlet manifold. A laminated metal gasket seals the manifold to the cylinder head. The same gasket also seals the inlet manifold to the cylinder head.

A flanged connection on the left hand end of the exhaust manifold provides for the attachment of the turbocharger. There is no gasket used between the exhaust manifold and the turbocharger. The turbocharger is attached to the flange with three bolts.

A second flange, located centrally at the rear of the exhaust manifold, provides the attachment point for the EGR valve. The EGR valve is attached to the exhaust manifold with two screws. A metal gasket seals the EGR valve to the manifold.