Alloy blocked M3

[Sunbmw]

Right, Is it possible to create an Alloy blocked M3. What started me thinking was we had a 96 328i in the workshop today, and correct me if I am wrong but these have an aluminium cylinder block. Now then, are any of the parts from the 3.2 M3 engine interchangable, and could you stretch the cubic capacity to 3201 (or more!!!) I love things like this, starts everybody thinking.

[JamesM3M5]

You can't bore the aluminum (or aluminium) block. It's a silicon-based cylinder lining that is precipitated out of solution from the aluminum alloy right at the surface. It gets hardened and bored to spec, and that's how you can run an aluminum block without liners.

You can try to put liners in, but there is very little wall thickness between the cylinders (91mm cyl spacing, IIRC).

Advantage is obviously weight savings, but BMW used the iron block for the S50 and S54 engines for a reason--strength.