<VV> Bell Housing Seal

[mhicks130 at cox.net]

I don't have a dog in this fight, but the "discussion" got me curious so I did some research.  I found some good information out on the web and specifically the following:

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from:  http://www.rlhudson.com/Shaft%20Seal%20Book/intro-primer.html)
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 "Generally speaking, hydrocarbon-based elastomers tend to offer better abrasion resistance than fluoroelastomers. 

Fluoroelastomers (FKM) are thermoset elastomers containing fluorine. Fluoroelastomers make excellent general-purpose seals due to their exceptional resistance to chemicals, oil, and temperature extremes (-15° to +300° F). 

Polyacrylate is a copolymer which offers good resistance to petroleum fuels and oils. Resistant to flex cracking, polyacrylate also resists damage from oxygen, sunlight, and ozone (due to main chain saturation).

polyacrylate is slowly being replaced by fluoroelastomers and hydrogenated nitriles (though both are more expensive)."
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The temperature ranges I saw tended to show more like 90 to 100 degrees (F) difference between what Viton and polyarylate could take.

Personally, I wouldn't have a problem with either material in a crankshaft seal based on what I read.  I'm no expert though, just a curious fellow.

mikeH