Question on all-aluminium engines???

Question

Advantages and disadvantages???

Answer 1

I don't know of any "all" aluminum engines, con rods, bearings, rings cylinder liners, cams, ect, are not usualy made from alum.

If you mean crankcase/cylinder/head combos, then I would say two big advantages, higher strength to weight leading to higher hp to lb ratios. And secondly and in the long term wear issue, differential expansion between high pressure seals (head gasket most usualy) leads to shearing of paths through gasket and head leaks. Very very common in many aluminum block/cylinders (with steel cylinder jackets) and cast iron heads. So common in many toyota engines that you can almost clock the 350,000 mark by the head leak.

Answer 2

Huge advantage: weight - much lighter than cast iron - easily yields more power per pound of engine weight.

Disadvantage: rigidity, cylinder wall wear and gasket and sealing concerns caused by excessive expansion and contraction.

Answer 3

I agree with oneirondriver and to add to it in the casting process porosity of the aluminum is a big problem also with minute leaks of fluids. It was also a big problem with aluminum calipers too