I was wondering what you guys adjust your rockers after zero lash for hydraulic flat tappet cams? 1/4, 1/2 turn ??? Any track proven times to see which runs better?
Is there also a limitation on cam size for when you want to adjust your rockers by going to TDC and adjusting the half that are at base circle and then I believe go another 360 degrees and adjust the rest that are at base circle? I have heard that when your cam lift gets a little higher you cant do it this way is that true ?? Thanks

 

Adjusting hydraulic lifters sets the preload inside the lifter. It won't change how much the cam lifts the rocker to open the valve unless it's too loose or overly tight which will cause a lot more problems. Too loose and they don't open the valves enough and clatter. Too tight and the valves won't close. Proper lifter preload is around .030" or about 1/2 turn from zero lash.

Remember, it's a hydraulic lifter. When the engine is running, there's oil pressure inside the lifter and fluid can't be compressed.

I've adjusted my valves with #1 and #6 at TDC and have also adjusted the valves on cylinder at a time. I've got a lot of duration with a roller cam and have seen no difference.

 

No, dont worry about it. Follow the factory procedure, you'll be fine.

 

Thanks for the help guys! So most would say 1/2 turn past zero though ?

 

On a typical stud used for a SBC, yes. That would provide for .021 of preload on the lifter which is within the typical specs for most hydraulic lifters out there.

 

My old 383 with a comp hyd roller works best at 1/4 past zero lash. Not a street car, and I shift it at 6800. Does NOT float the valves. I run 986-16 springs, setup @1.900.