Gear or Shat Driven Overhead camshaft?

[jz78817]

@Hail_Ants

Ok, so belts *originated *in European makers, but that only reemphasizes my point. The foreign car manufacturers (and car buyers) were all in shambles after WWII. They had to innovate cost-saving measures. The US makers went gangbusters from the 40s until the early 80s (when imports finally caught up). Until then the US auto industry had little to no use for cost-saving ideas because the market had no demand for them. Once they were in trouble cheaper designs like timing belts instead of gears or chains made financial sense (for the manufacturers anyway).

But again, they are always a disadvantage. They are the single weakest link in any engine design that uses them. Outside of high-performance muscle car engines I have never seen nor even heard of a timing chain failing.

Ladies and Gentlemen, the Dunning-Kruger effect.

[botsgotme]

@jz78817

at least as far as street engines go, the only people who deride OHV engines as “low tech” are Internet dummies who think horsepower per liter is a useful metric. Vs. an OHC setup, pushrod engines are more compact, can be lighter, and make equivalent power and economy.

check it. On the left is a 4.6 liter, DOHC 32 valve V8. On the right is a 5.0 liter OHV engine. Which one do you think would be easier to package under the hood of any given vehicle?

Indeed-GM is using pushrod technology for the next advance in variable-displacement engines. It is easier to turn off cylinders (for higher fuel economy) using pushrod activation. I have never understood why passenger car engines need to rev past 4000 RPMs anyway-but that is what the OHC engine people like.

[fire_hazard]

No free lunches in engine design.

In Europe volumetric efficiency is/was important for taxation reasons. Large engines and fuel are punitively taxed across Europe and have been for a long time.

American motors tended to be big and low stressed for long distance reliability.

Engineering is just one of the influences on design.

My car has just 1.8 litres but 20 valves and a turbo for tax reasons. I change the timing belt myself and go by age rather than mileage.