Very true, perhaps the Twin Cam MGA is the exception that proves the rule.
Seriously though, I think it was one of the great British motoring tragedies that MG failed with their twin cam engine.
They went so close to getting it right. If it had of delivered on its promise perhaps it could have flowed through to the MGB making it a far more exciting car and who knows where from there. After the failure of the twin cam MG seemed to have a total aversion to high performance engines, there MGC‘S six cylinder engine more closely resembled a truck engine and when they were eventually dragged kicking and screaming into the V8, they made dam sure it was the least tuned version available.
It is interesting though that the twin cam’s problems were not associated with its numerically challenged main bearings. I read sometime ago that after years of investigating and tuning the twin cam that the actual cause of its failure was discovered. No, it wasn’t excessive compression ratio or dodgy advance mechanism but apparently it was fuel foaming in the bowl at a certain (high) rpm that led to a weakening of the mixture at that point.
As an aside, I was talking to an old MG tuner who said that they would actually remove two main bearings form the five bearing engine when racing which would liberate more performance, presumably from less drag, yet it would still hang together at high revs.
My MGB has the late 18V engine and the crank is a thing of beauty, no doubt capable of absorbing far more horsepower than the antiquated five port head could deliver.
We do know that the Norton crank was a weak spot of our bikes and the failures associated with the Combat engine probably sealed the fate of our bikes although it was a rather slow burning fuse. Perhaps a rock solid crank could have saved the reputation of the bike and maybe, just maybe, provided enough breathing space for Norton to drag itself into the last half of the twentieth century.
just a few thoughts
Alan
