chrisyork said:
Because P10 was aimed at the company car market, it was a much simpler car than P8. When it then morphed into SD1, it retained this simpler spec, hence the live axle in an SD1. Mechanically and bodyshell wise, SD1 was pretty well pure P10, but it had "gained" the Triumph six pots from the cancelled Triumph project and also an Austin Morris quality interior and other cost saving engineering.
Chris
Hm. Very interesting...! I was under a slightly different impression from a few contemporary articles I've read with King/Bashford. I understood P10 to have started life with base unit construction - essentially a cut-down version of P8's. This would have greatly rationalised the production lines as well as maximising component crossover between P8/9/10. It is known that up to 1969 (the 'Talk at the Top' article with King/Bashford/Wilks/Stokes), deDion was confirmed as the rear support "in all future Rovers". I also know (but can't remember where I read it) that the mounting points for P8's "true" deDion (telescopic halfshafts) are in the same place as the axle mounts on P10-SD1. To my mind, this would demonstrate a far more impressive spec for P10 than eventually emerged as SD1. If the deDion suspension was a given at the laying down of spec, then the live axle must surely have been a substitution
after the cancellation of P8, when production of deDion for one car only became less profitable than developing a simpler system on the same mounting points.
If base unit construction was also proposed, then surely the front suspension would have been derived from P8 also, or at the very least a more traditional British double-wishbone setup than the Fordist MacPherson system that arrived with SD1.
The clincher for me is the size of SD1's engine bay. Imagining for a moment that the twin-cam 16v 2.2 litre derivative of the P6 2000 engine had come to fruition, and that the same level of attention to detail and engineering perfection as P6 had gone into its execution, how could the engine possibly have been mounted? Canted or otherwise, the engine bay is FAR too wide, even for the V8. I was once told that the best was to mount a 4-cylinder engine for maximum NVH reduction is to 'hang' it from the joint of the cylinder block and head. That keeps the weight as low as possible and prevents most of the 'wobbles' from the bottom of the engine transmitting to the body. I just can't see how you'd achieve that in the pit that is the SD1's engine bay. Unless.... a base unit construction with broad inner wings and a pair of high-mounted inner chassis rails similar to P6 had once been there...??
It's understandable that these things would have been axed. Kitting out an executive fleet car with Mercedes-killer running gear is all fair and well when the technology is borrowed off the bigger brother, but once he'd been sent away to a convent, there's no financial sense in over-engineering the fleet car. Unitary construction was also undoubtedly cheaper. But SD1 just seems a little
too tardis-like - there's too much empty space in it for it to have always been monocoque.
Michael