Precombustion chamber in the cylinder head of a diesel engine

A precombustion chamber construction in a cylinder head of a diesel engine, the cylinder head bounding a main combustion chamber of the engine, said precombustion chamber construction comprising means in said cylinder head defining a precombustion chamber communicating with the main combustion chamber via a flow passage and including a member in said cylinder head provided with said gas passage and a body supported by said member and facing into said main combustion chamber to form a gas baffle for combustion products passing through the gas passage from the precombustion chamber to the main combustion chamber, a mushroom shaped body including a cap disposed in said main combustion chamber and a stem received in said member, said body and member defining a gas duct therebetween, said mushroom shaped body comprising four longitudinal webs at an angular spacing of 90 degrees, said webs projecting from said stem to said member, and at least one transversely extending pin extending through a respective pair of webs and said stem into said member and being covered by said webs in said gas duct.