I was reading that they all have a problem with the bearings wearing out fast. Also it said the alluminum will become stressed and break or something? I figured someone would buy roller rockers for improved wear life but whats the point if the $300 set of rockers give out anyway?

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I'd rather be historically accurate than politically correct!

 

AFAIK there's nothing inherent in their bearings that makes them wear out fast.

Aluminum fails by way of "fatigue". What happens is that after a certain number if stress cycles, the metal suddenly will just break. It usually gives little or no warning. This characteristic of aluminum is why airplanes have such a rigorous inspection and replacement cycle based on hours of operation and landings.

They were originally meant for racing. Even in the most extreme sort of endurance racing, they only have to last 24 hours or so. On the street, at 50 mph average, 100,000 miles is 2000 hours of operation. Big difference in how you go about designing for "improved wear life". They won't wear out in 24 hours, and they'll withstand a helluva lot more punishment than stock sheet-metal ones; but they don't have lifetimes in the thousands of hours.

A good compromise is the Comp steel ones. They're lighter than aluminum, because they don't have to be so huge to combat the "fatigue" problem (steel doesn't fail that same way), they're usually narrower so they fit better under stock valve covers, and they will go thousands of hours (hundreds of millions of stress cycles)between failures.

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"So many Mustangs, so little time..."
ICON Motorsports

 

No, Crane sells good quility roller rockers for around $160 in JEGS, and these things will not break or wear out. The only two way i can think of would be, high rpm with a big solid roller and alot of spring pressure, or other bad valvetrain geometry problems. But you would bend a push rod first, before breaking a rocker. The $300 ones are real good quility and can be run for hours at high rpm like 8000 to 9000 rpm, like nascar engines, so for a street engine its overkill anyway. Hope that helps

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