Originally posted by Red Fox
Should I wrap the engine in blankets/hay/...
No, that's the procedure for winterising a horse!
...but seriously, the most important thing is to make sure that water is allowed to drain out. If any (fresh) water is trapped in a waterway, it will expand when it freezes, and crack the component. It doesn't matter how strong the component is - freezing water WILL expand and crack even a strong casting