I would suggest flushing out the engines and oiling them before use. As mentioned, just remove the plug and backplate. If any loose rust has formed, it will flush out first running and rust is iron oxide, which is a lapping compound. For that reason also make your first run "super rich" to lessen the wear.
If you need extra castor oil, another place to get it is at the hobby shop. Sig sells it.
Some of the racing car engines run at a very high RPM and are designed to run on specific fuels. You might want to do a search on that engine and see what others have been using...and more importantly, what they are NOT using.
One famous engine guy posted (a couple of years ago) that some cars are using 5% lube...albeit probably a very special and expensive lube.

George