Help with Valvesprings and valve float. Noob

gzig5 said
Sure, but they were supported the full width of the rocker, right? take the bearing out of the OPs rockers and replace with same width bronze and you get maybe 1/2 to 1/3 the surface area. No way you will maintain an oil film with that small of an area with any kind of spring pressure. If you could, they would be doing that on race engines. Bearing width = friction and friction robs HP.

If putting bushings in each side of these PQ rockers, you get right around 62% of the overall rocker width as surface area... right at 0.75" total bushing length (.375" bushing per side) per rocker in a 1.2" wide rocker body. (An SBM rod bearing is just over .8" wide BTW.) Plus the inner bore on these rockers is a larger ID than the shaft and the oil enters there and forms a reservoir of oil in there. So it'll probably do better than you are fearing; the saving grace of a sleeve bearing of any type in this application is that the speeds are very low..... just a small fraction of the speed seen at the rod and main bearings.

Yes, it makes more sense to put in a full bushing (which is doubtless a driver to using a full bushing), but that is just too much machining on these to make sense (to me). And the bushings will have 50-100 times better bearing area than those teenie-tiny 1/4" long needles spaced far apart. These are not set up side by side like you normally see in a U-joint cup, but are spaced widely. I looked them up, and those needle bearing assemblies were designed for a completely different application than this high, oscillating load. The 'designers' (and I use that term quite loosely!) just saw a cheap part and said "Those will work for those stupid Americans!"