[Continued from previous post]

As best I know, BMW engines -- including the main engine blocks -- are nowadays made out of aluminium, with the possible exception of the diesel in the 324/524 [t]D[i]. This used to be seen as High Black Magic back in the seventies when I was a kid, when even aluminium cylinder heads where looked upon with some suspicion and quite a lot of trepidation. During the eighties, though, aluminium heads became rather the norm, and I'd say that by now even aluminium engine blocks are rather "normal". With modern material science (nickel-cadmium-silicon surface treatments for pistons and cylinder linings, etc), I don't think that the longevity of an aluminium-block engine has to be any the worse than a traditional cast-iron lump. (For one thing, making the block out of the same material as the head would tend to eliminate problems due to different thermal expansion coefficients, which were the main cause of problems -- and thus, suspicion and trepidation -- with aluminium cylinder heads in the seventies!) Sure, any *new* engine can have teething problems... But those are usually ironed out within a year or two of its introduction to a larger market.

[To be continued...]