These are xrays of a K&B .40 marine motor for a boat I used to have many many years ago.   I had a lot of fun but eventually got bored with it.   I don't have the boat or the motor any more but I hung on to the xrays. They were taken in the seventies.
I'd be willing to say that these are probably the only xrays of a radio control engine on the internet.  If anyone disagrees with this claim, email me the link and I'll post your name and the link (which incidentally will make you instantly famous).

Click here if you are unable to download or view the large pictures.