These are raw cylinder head castings that come into BSD Engineering to be machined into usable items. The first operation is the manual milling machine; this takes off the excess flashes (they’re actually cast a little bigger in size, and various methods are then used to shrink them) as there’s always surplus material to deal with.

It’s worth noting that in summer (especially) temperature management is important – aluminium expands as it gets warmer so to get the correct tolerances when machining you must pay careful attention to the ambient temperature and keep a consistent environment.

Then the head goes onto the 4-axis Haas, where the combustion chambers and mating surface are machined into shape. Dowel holes are also added at this stage so we can locate the part on the 4th axis for the second operation, and complete all the machined faces without having to remount the part. We cut the valve seats, machine water pump location.

There’s some manual finishing off and when all the work in the shop is done we turn out a perfectly in tolerance part ready to power a classic car!

Classic car cylinder heads, ready for the BSD Engineering treatment

Classic car cylinder heads, ready for the BSD Engineering treatment.