ok all you beemaphiles, when did BMW start using alloy blocks? and how do they compare weight-wise to the more common choices?

Must be plenty of old beemers at the wreckers these day

I'm by no means a Beemophile, but I believe the first (straight-six) aluminium engine would be the BMW M52. It is 160 kg compared to 190 kg for the M50 engine, and was introduced in 1994 as the M52B20 in the 320i.

And here's a little note from bmwworld.com:
Do not buy an M52 320/323/328 with an alloy block made before 3/98 unless it's had a new engine under warranty or you get a compression check done. Sulfur in fuel causes premature bore wear which shows as a bad idle and lack of power. Only solution is a new block.

[Edited on 17/10/05 by Garbrand]

As GarBrand said it was about 1994/95 ish although it depends what car as to to when the change was made i beleive.

alloy 320i (2.0) engines are rare
the 2.5's from 323's are alloy, as are the 2.8's from the 328 and the 3.2 from the M3 Evolution. Plenty more info here: http://www.unixnerd.demon.co.uk/enumber.html

There are plenty of BMW's at my local scrappy, but if you need a specialist BMW breaker then try www.fabdirect.com who will have any BMW engine you'll ever need inc the bigger ones like the 4.4 V8 and 5.0 V12!!!

HTH