I'm looking to design a range of diesel engines for use in road cars (for when i win the euro millions ;) , consisting of a flat 4, straight 6 and v8. all with a cylinder capacity of 666cc (per cylinder). As we know the biggest downfall of diesel engines is the weight, especially that of the crank and pistons. The crank and rods can be replaced with titanium versions and the block can be replaced with aluminum. What can be done to lighten the weight of the pistons? Bear in mind I am intending these engines to be direct injection so they will need enough height for a combustion chamber. I've heard that beryllium is used in f1 engines, would that stand up to the pressures in a diesel engine?