"Stefan" wrote in message
...
Matt Barrow schrieb:

You're worrying about virtually nothing!
http://www.avweb.com/news/maint/182883-1.html

Shock Cooling: Myth or Reality?

Powerplant management guru Kas Thomas of TBO ADVISOR examines the physics
and metallurgy of "shock cooling" and concludes that, contrary to the
conventional wisdom, it is not a major contributor to cylinder head
cracking.

Lycoming says otherwise:
http://www.lycoming.textron.com/supp...Operations.pdf

Lycoming
Sudden cooling is detrimental to the good health of the piston aircraft
engine. Lycoming Service Instruction 1094D recommends a maximum
temperature change of 50° F per minute to avoid shock-cooling of the
cylinders.

Thomas offers data and evidence, Lycoming offers anecdote and legend.

Takes yer picks.