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Old 02-07-2011, 03:26 PM   #6 (permalink)
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Originally Posted by UFO View Post
Weren't the original VW air cooled Beetle engine cases made of magnesium alloys in the 40s??
Maybe it was as early as the '40's, a big part of the reason that they used magnesium is that it doesn't have the same thermal expansion that aluminum does, so with an air cooled engine that tends to run hotter having your crank case expand would lower your compression as it heated up.
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