Thanks, Conceptual, I've forgotten about the Perendev engine. AFAIK, it was touted four or five years ago as the best invention since ice cream, but the site went dead and the american associates of Mr. Brady (?) "disassociated" from him. I've already expressed my views about perpetual motion machines, but, hey, they had the American Antigravitation Society (if I remember well) behind them...
Trying to stay on thread, ceramic engines were tried by Toyota in the 80's. They were able to run so hot that, if I remember well, did not need cooling systems, which is a strong advantage. Also, the Carnot cycle works better the higher the difference of temperature between the engine and the environment. Unfortunately, they were the devil to manufacture and the gains were small: a sizable part of what you "won", in heat conserved in the combustion chamber, you lost to the oil. I believe Toyota used the experience to develop ceramic spark plugs and brake pads that are able to work at higher temperatures, but I'm not sure: all I know is that they appeared a few years after.
I think Isuzu also tried to build another ceramic engine. I also remember an old drawing in the 80's about a rotary Mazda engine made with ceramics.
Ford did something similar in the same epoch, using zirconium based ceramics. They have very low heat transfer rates and good shock properties.
If someone is interested in low heat rejection engines, you can read here a SAE paper on the subject:
http://personalwebs.oakland.edu/~leidel ... 1-0405.pdf
I think that most modern F1 engines have a lot of parts made of carbon fiber, which makes hard to find a better material from the point of view of strength/weight.