I am model engine builder and can tell you, you can use cast iron from old camshaft (between cam are cast iron easy to turn in lathe) for piston and steel from drive shaft to example from front wheel drive car for sleeve (cylinder).

Picture of the first modelengines who are not beautyful but works well and easy to start and later more better and beautyful..

Go to Yahoo Groups and search after model engine builder for forum..

Jens Eirik