Bentley dismantles, 3D-scans its famous 4.5-litre Blower

Last September Bentley announced it was planning to build 12 recreations of Sir Tim Birkin’s 4 ½ litre “Blower”. To do that, it would first need to completely dismantle its own Blower – Birkin’s own, the most famous of the four originals – and 3D scan all the bits.

Well after some 1,200 man-hours, that process is now complete. Birkin’s Bentley now exists as a 2GB digital model, something for the engineers to work from as they construct “Car Zero” – the prototype – and eventually the 12 customer cars.

Last month Bentley CEO Adrian Hallmark told us in the course of stripping the Blower down to its component parts, his engineers had discovered it wasn’t even symmetrical and had been re-built in the mid-Fifties.

The recreations will be symmetrical, but otherwise mechanically identical to the four original cars Birkin commissioned in 1929. That means a four-cylinder, 16-valve engine with an aluminium crankcase with cast iron cylinder liners and non-detachable cast-iron cylinder head, an exact replica of the Amherst Villiers Mk IV roots-type supercharger, a pressed steel frame, half-elliptic leaf spring suspension, 17.17-inch drum brakes and worm and sector steering.

12 sets of parts will be created using a mix of the original moulds, tooling jigs and hand tools, as well as more modern production methods.

As well as engineering the new-old Blower, the CAD model is being used by Bentley’s design department to help the 12 lucky individuals spec their cars. Said wealthy individuals can choose their own exterior and interior colours and materials. Now that’s just asking for trouble…