hello all . i have a set of johnson ta-1405j lifters i have been asked what the preload setting is can some one tell me please also any other information i should now . many thanks kev
30 to 60 generally, looser = little more response, tighter = more consistent valve action up in the rpms Some fellas run them real loose at 20
If you have type with e-clip retainers you can run on loose side but the type with paper clip like retainer I wouldn't. I had that type come loose and make a mess. Also, depends on oil pressure...if higher than 85lbs revving they can pump up if too much pre-load ot too much oil pressure. We had a motor that wouldn't rev past 5500 with pre-load to spec....motor was tight and fresh 95lbs oil pressure. Put thinner oil in and it revved to 6500 with 80lbs pressure
If mostly street driven i aim for .050. if mostly racing I shoot for .025-.030 to help prevent pumping it up and holding the valve open
I've seen stock lifters with more than a quarter-inch of plunger travel. I've seen "high performance" hydraulic lifters that had only a few thousandths of travel. Some guys think the hot set-up is to preload the plunger to almost the bottom of it's travel--to prevent excess bleed-down from reducing valve lift and pounding the valve train. Some guys think the hot set-up is to preload the plunger to almost the top of it's travel--to prevent the plunger from "pumping up" and holding the valve open. I think that if you have adequate valve springs to suit the camshaft and the RPM, and the lifters don't have an excessive bleed-down rate, it doesn't really matter where the preload ends up as long as it's within the limits of the lifter plunger travel. This opinion might change for an engine that has race-stiff valve springs. I might lean more toward the "bottom of the travel" philosophy in that case. Of course, with severely-limited plunger travel, you can be near the bottom of travel AND be near the top of travel. Best of both worlds, but no margin for valvetrain wear. Remember that with shaft rockers, pushrod length affects only lifter preload. When the rockers are the Chevy-style adjustable system, pushrod length also affects valve train geometry in addition to lifter preload.
