[Land-speed] Magnesium

[tom sarda]

Hey, List,
Does magnesium transfer heat differently than aluminum? The question arises as a result of work I have done on six of the cars I have worked on that run at the local short track. I have rebuilt  the Quick change rear ends. Five of the rears are aluminum and one is magnesium. I have measured the temps on each after racing as soon as the return to the pit area...as soon as i can get to them. The temps are measured at the bell(on the side) and at the rear cover where the spur gears are housed. I expect to see the temps to be higher at the cover than the bells. The aluminum  rear ends run anywhere from 206 to 225 at the bell and 225 to 244 at the cover. The magnesium runs 270 at the bell and 290 at the cover. (Track temp last night was 118). Is the mag rear end holding more heat than the aluminum?
 the lubricants vary from team to team with Mobil 75/90 the most popular, Royal purple and Gibbs 75/110 ars also used. The mag rear uses Gibbs lube. Went to it after last weeks temps were 10 degrees higher at the cover.
Any one have an idea about  aluminum versus magnesium? Thanks in advance for your thoughts.
Tom