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Composite pushrods make a LOT of sense, and frankly shouldn't be that expensive to make. Pistons and con rods make less sense to me. I assume that for products like that they are using a molded chopped fiber construction, which really gives up much of the structural capability and benefit of composite parts. And their claim of better thermal properties doesn't make a lot of sense - graphite conducts well along the fibers, but poorly across the fibers and plies. Chopped products make that worse.
Now, if you want to make a lightweight piston, lithium aluminum comes to mind (as was used in the Space Shuttle external tank). Lower mass and higher stiffness for a lot more money.
Do make pistons, connecting rods and other engine parts. Very lightweight. Could not get the pictures to load from site. Looking around, for other's making them also.
Love to put DX block. Maybe for guys to afford in 5 to 10 years. I will be to old.
I did some poking around and reading everything I could. The original set of connecting rods cost $18,000 a set for the engine they used them in. They have that cost down to $10,000 now. They claim that they are "hand laid" composites. Another statement was that if a piston broke, it shattered....no chunks to destroy the engine.
Way back Yunick tried carbon fiber push rods, first dyno test with them being filmed super slow mod, they desinerated at around 7000. The technology has advanced greatly in 45 years and now they should work, but all he had to show was a pile of black dust
Composite pushrods make a LOT of sense, and frankly shouldn't be that expensive to make. Pistons and con rods make less sense to me. I assume that for products like that they are using a molded chopped fiber construction, which really gives up much of the structural capability and benefit of composite parts. And their claim of better thermal properties doesn't make a lot of sense - graphite conducts well along the fibers, but poorly across the fibers and plies. Chopped products make that worse.
Now, if you want to make a lightweight piston, lithium aluminum comes to mind (as was used in the Space Shuttle external tank). Lower mass and higher stiffness for a lot more money.
Their claim of thermal properties makes sense actually. They're claiming less thermal conductivity will keep more heat in the chamber. Certainly questionable whether this really matters that much (as the thermal path through the piston is pretty poor anyway) but the conductivity would be less than aluminum. They're also claiming less thermal expansion than aluminum for tighter bore clearances, which is definitely true. Composites have exceptionally low CTE.
That said, I agree with the rest of your assessment: the pistons/rods seem like a questionable use for composites.
