Quote:
Originally Posted by jeff88
Other than cost, why doesn't each cylinder have its own head?
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Aircooled 911s do. Each cylinder is separate, each head is separate, and then there is a "cam tower" that is a single piece that goes across the whole set, linking them together. It does make for somewhat modular construction, and the head castings can be smaller and cheaper to make. And I think there are air passages in between the individual heads? I forget...
If you have a single head bridging across the cylinders, you get easier coolant passage layout (when not using air, at least). Plus the single large casting is much stronger and resists deformation a lot better than smaller individual castings. And there are fewer interfaces to leak, just one or two large ones rather than many smaller ones.
A number of aero engines also used separate cylinder heads, and separate rocker boxes as well. But in general those are built using 1920s technology. Aircraft engine development lags astonishingly behind automobile engine development in many ways.
-soD