Cylinder head, 25/30, turbulated, to end of O2 series

During the course of the production of the early 25/30 cylinder heads the space for coolant around the spark plugs was increased. This modification was introduced at the start of the M2 series. In order to accommodate the extra volume around the spark plugs it was necessary to fit longer studs along this side of the engine; these are the studs that are fitted to the crankcase.

The cylinder heads that we manufacture are all to the later pattern, having the extra volume for coolant. If it is necessary to fit a new head to an engine from an L2 (early) series car the studs along the spark plug side of the engine will have to be changed to the later longer stud. This can only be done by lifting the cylinder block, as the increased diameter at the bottom of the studs will not pass through the block. The longer replacement studs are part number GER223.

The 'turbulated' description of the cylinder head refers to a detail of the combustion chambers. It was fitted up to the end of O2 series chassis. For more details refer to this link.