Roller rockers 1.6 no needle bearings affordable

pishta said

They have 'em in U-joints, same oscillating motion, but I think the reason is to have the smallest bearing available in there (so as to have more meat inn the axle) and to spread the load across the largest area. You couldnt run a floating (hydrodynamic) bearing in there as there is no pressurized oil as in a rocker arm. Roller bearings dont do that well but they include their own hardened races. I think the floating bearing in the rockers is the best for the job. Cranks live for 100s of thousands of miles on hydrodynamic wedge bearings.

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I took all the needle bearings out of my PRW's aluminum rockers and the are something like only 1/8" or 3/16" long each, and are spaced apart bay a sort of internal cage. The U-joint needles are packed, side by side, 2 or 3 times more tightly and are many time longer and the angle of motion is relatively small.... So a lot lower loading.

And they are in grease, which may be a different lube situation than oil. So I don't really think they can be compared.

I was reading up on some of later LS engines which come with needle bearings on the rockers, and they suffer the same fretting failures. There are 'bushing and trunnion' kits out there to replace them.