Setting valve lash with new, non filled hydraulic roller lifters

74Scooter said

How the heck did he bend valves? If you put in too much preload you essentially turn the lifter into a solid when you bottom out the plunger. Sooo he got too much valve lift and it hit the piston top?

Getting ready to install a new set of heads on my 360LA and 1.6 ratio rockers which will increase my valve lift by about .030 IIRC. Thread is very interesting to me. I was thinking zero lash + 1/4 turn.

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Sounds like pre-oiling the lifters kept the plungers from taking up the preload so it hung the valves open. I had that happen putting together my 5.9L Magnum short block with Edelbrock top end. I had to carefully rotate the engine every hour or so until the lifters bled down to the proper plunger depth and the valves were actually seated when on the cam base circle. I didn't pre-lube the lifters but somehow from sitting in a junkyard for a long time some of them pumped up.

All this arguing about preload, check out this page from Hughes and look at the part of the table "Standard Lifter pre-load"... https://www.hughesengines.com/Index...Z2UgTWFnbnVt&level1=Q2Ftc2hhZnQ=&partid=30210

I put together my 360 with around .080-.085" preload reusing the factory Magnum roller lifters and the valvetrain is dead silent. 8000+ hard miles and no issues either.