FYI: 2010 Evo X Plastic Valve Cover
g'damn you're supposed to price to SELL not price to KEEP! 
i'm not so sure if everyone will be keeping their evos in 15 years...if it will last that long. i think by then there's other things to worry about, you know, like we're running out of oil
(well strictly speaking there's oil around, but it's too deep to be drilled out) and by that time we'll all be running on electric evos!

i'm not so sure if everyone will be keeping their evos in 15 years...if it will last that long. i think by then there's other things to worry about, you know, like we're running out of oil
(well strictly speaking there's oil around, but it's too deep to be drilled out) and by that time we'll all be running on electric evos!
Not to mention it allowed them to spend that much more on materials to make the fatter side skirts...
It's not all that crazy for a car to have a plastic valve cover. Look at BMW. They've been doing it for years, and it's not squeeky toy plastic either. It's pretty tough. I have yet to see one break.
No one's really address the strength or "weaker" argument against the plastic yet, so I'll give my engineering $0.02 here.
Tensile strength of many cast aluminums isn't that high. Assuming they use a mid-grade nothing special cast Al, its tensile strength will be around 30ksi (30000 psi). It's a bit hard to compare a polymer to a metallic apples-to-apples in terms of strength, but many injection molded composites (which this "plastic" cover surely is) can have tensile strength levels from 60-100ksi. Therefore, it's most likely the "plastic" version is stronger than the aluminum version, but without knowing exactly what material each of them are it's impossible to make a direct comparison. But i'd place my money on the "plastic" being stronger.
As an aside, from an engineering perspective there's nothing wrong with the "plastic" version. The aesthetic argument is a different story though.
Tensile strength of many cast aluminums isn't that high. Assuming they use a mid-grade nothing special cast Al, its tensile strength will be around 30ksi (30000 psi). It's a bit hard to compare a polymer to a metallic apples-to-apples in terms of strength, but many injection molded composites (which this "plastic" cover surely is) can have tensile strength levels from 60-100ksi. Therefore, it's most likely the "plastic" version is stronger than the aluminum version, but without knowing exactly what material each of them are it's impossible to make a direct comparison. But i'd place my money on the "plastic" being stronger.
As an aside, from an engineering perspective there's nothing wrong with the "plastic" version. The aesthetic argument is a different story though.
But yeah this must be a polymer glock pistols are made of it and are pretty damn strong

The end results are the important part for me
So yes i rather sit behind a bullet proof glass vs the traditional when somebody shooting at me. And i really dont care how they made it

Glock pistols are the other example for plastic strength, and durability.
Last edited by Robevo RS; Nov 6, 2009 at 12:14 PM.
all I'm saying is look at a plastic valve cover on a 1981 258ci jeep straight six vs say a 1979 bmw 3.3l straight six and tell me which one is still usable.
hint: plastic 258 jeep valve covers all cracked and warped.
hint: plastic 258 jeep valve covers all cracked and warped.

Originally Posted by frankiago
Not to mention it allowed them to spend that much more on materials to make the fatter side skirts...
oh and btw, the back door no longer comes with that little clear sheet of plastic on it (if you know what I'm talking about)
So I assume that on the 2010's mitsu did at least address the paint chipping issue
4b11 "blacktop". seriously though, those plastic valvecovers last 10+ years. as a tech, we had plastic valvecovers on our cars and they could be dropped, thrown, stepped on, and still be ok. you couldn't smash it with a hammer, but who does that.

I love them , but they need a lots of maintenance.
And the 1981 technology is not even close to the 2009 + , i think we can agree on that one at least.
Take a look at just on the computers.

I dont think that was a good example at all.
By the way BMW straight six warps ...






