What are the disadvantages of a hydraulic valve lifter?
One of the disadvantages of a hydraulic valve lifter is that it cannot follow as aggressive a cam profile as a mechanical design, thus limiting the engine’s power and operating speed.
How do you adjust the valve on a hydraulic lifter?
When adjusting the valves on an engine with hydraulic lifters, you are not really setting the lash or clearance–you’re actually setting the preload on the lifter through the pushrod and rocker arm. The traditional adjustment on a hydraulic lifter is zero lash, followed by a predetermined amount of turns on the hold-down nut.
Why are valve lifters still used in drag racing?
Even so, most hydraulic lifters can’t match the performance and reliability of solid lifters over 8,000 RPM. That’s why high revving engines in NASCAR, drag cars and circle track cars still use solid lifters.
How can pump up be not the lifters fault?
Pump up is normally not the lifters fault. Think about it, oil being fed thru an orifice into a chamber of a fixed dimension. How can that go wrong? Here is a way, the valve is heavy, the valve spring is weak, the cam lobe is aggressively actuating the valve in a manner similar to a baseball pitcher throwing a fastball.
One of the disadvantages of a hydraulic valve lifter is that it cannot follow as aggressive a cam profile as a mechanical design, thus limiting the engine’s power and operating speed.
What should the pressure be for a deactivation lifter?
The AFM lifter bores in these engines have a spec of .843-.844, and the deactivation lifters require 22 PSI of pressure to release the locking pins. Taking these two things into consideration a lifter bore that is even slightly worn could bleed off enough oil pressure to prevent the lifter from unlocking.
Even so, most hydraulic lifters can’t match the performance and reliability of solid lifters over 8,000 RPM. That’s why high revving engines in NASCAR, drag cars and circle track cars still use solid lifters.
When adjusting the valves on an engine with hydraulic lifters, you are not really setting the lash or clearance–you’re actually setting the preload on the lifter through the pushrod and rocker arm. The traditional adjustment on a hydraulic lifter is zero lash, followed by a predetermined amount of turns on the hold-down nut.