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Amicale Spitfire
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Museum main entrance |  Boîte de vitesses "vrillée" | Twisted" Gearbox 


This is the inside of the modified 3-rail GT6 Mk3 gearbox fitted to our 1296cc Mk3 Spifire racer. Chris was racing at Loton Park on 18th July accelerating hard in 3rd gear when BANG, all the teeth broke off 3rd gear cluster, broke half the teeth on the laygear, jammed up the transmission causing a 30 degree twist to the spine of the input shaft.
Not shown is the tip journal broken off the mainshaft and the twisted tip bearing roller cage, and the handfull of metal bits. We have rebuilt and refitted the gearbox this week ready for racing at Shelsley Hill Climb on August 15th.
We are not sure of the cause of the failure, but as Chris swears he did not "miss" the gear change, we think that excessive play in the main and tip bearings allowed the laygear and mainshaft to flex sideways under the engine's 115bhp/100ftlb power, rise out of mesh and jump gearteeth with devastating results. The rebuilt box has no play !

Peter Hill
Last update 01/09/2018