Correspondingly, the FD4s capacity was raised from 72 to 2 litres. The catalogued outputs of the blower FD6 Mk6 were 175bhp at 2200rpm and a torque maximum of4401b ft at 1400rpm. Catalogued outputs of the blown and garage door opener vera FD6 Mk7 were 225bhp at 2200rpm and 6001b ft at 1400rpm. Equivalent figures for the Mk6 iteration of the FD4 at the same engine speeds at the sixes were 120bhp and 2931b ft.
The FD4 was not offered in turbocharged form. While many operators didnt experience garage door opener vera problems, others did. The pinch point was cylinder head design. There was a risk of cracking. But failures were not prevalent where Fodens with two-stroke fours or sixes were driven in a manner that respected their inherent characteristics.
Underlining this, 12-cylinder Foden two-strokes in naval service earned a reputation for garage door opener vera dependability. Powering generators for example, they operated at constant speed and were not prone to cylinder head cracking. Foden two-strokes were typically specced with four-speed crash box/three-speed auxiliary transmissions. Saved for posterity by Frank Wade, this prototype automatic was also under development. Among veterans whose Foden two-stroke know-how was acquired first-hand during the course of their working lives, there is clear consensus.