The reason for this Lancia V4 engine to overheat lays in the routing of the exhaust channels that are inside the cylinder head. Unfortunately cooling water flows around those channels and heats up the cooling water extensively. The cylinder closest to the exhaust manifold tends to overheat. Moreover the coolant flow in that corner of the cylinder head is very poor.
Our customer came up with the idea to build a cooling jacket around the affected zone and help the cylinder head to cool from the outside. Additionally the routing of the cooling lines was enhanced for a better flow.
The cooling jacket is mainly made from a half a steel tube and some sheet metal. The jacket was then laser welded to the cylinder head. The welding of course needs to be waterproof.