Perkins manufactured three marinised versions of Perkins 4.108 engines over the years, each with different options for the header tank used.

• 'Early' engines have the combined header tank/heat exchanger at the front of the engine and were fitted with a 60 mm diameter winged cap - for these engines choose our 'short reach' cap.
• 'Lowline' engines have the header tank at the front of the engine (heat exchanger at the rear) and were fitted with a larger 70 mm diameter round cap- choose our 'large' cap.
• The later engines were fitted with a Bowman type combined heat exchanger fitted on the exhaust side of the engine and were fitted with a 60 mm winged cap - standard fitment is our 'short reach' cap, but some early versions of this unit work better with our 'long reach' cap. To help you choose, please measure your cap height and compare with our annotated drawing above.

All of our caps are made in England from high quality components, comprising zinc plated steel caps, stainless steel springs and brass internals.