Thread: Plastic engines
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Old 01-27-2010, 02:01 PM   #30 (permalink)
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Originally Posted by TheEnemy View Post
From what I remember from a materials class I took (10 years ago now so I might have the terms a bit mixed up)

Most materials have a fatique limit, if you stay below that amount of force there is no permanent deformation of the material. Plastic doesn't have that limit, which means any force applied causes at least some deformation.

Now with the plastic engine block, unless it has a metal structure that is then covered in plastic that the head, and bearings bolt to, the crank will slowly over time stretch down away from the head. The engine will slowly loose its compression ratio, and will start dumping oil out of the front and rear main seals as they will become ovals instead of circles.

Truly a throw away design.
Imagine for a second that plastic doesn't necessarily mean the stuff your soda bottles are made of...

Plastic means any materials which contains properties which are plastic-like. They're using composites in the design because the composites are/can be made close to the strength of some metals with minimum stress warpage (into the thousandths of an inch per Nth force).

I'm not reading too far into it, because unless I cast one myself, I'll likely never see them, but it's still a rather interesting concept, just like compressed graphite, which also "would never work" before it was implemented, and eventually did work.
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