What is the difference between hydraulic and mechanical lifters?
On the outside they look the same, inside is where the difference is. The mechanical (or solid lifter) is just what it sounds like, solid with no internal movement. These lifters are designed to be adjusted at lash (clearance) and are to be used on camshafts that are designed for a lash setting. Mechanical lifters require periodic adjustment and are normally used for higher rpm. However the advantages are they have no internal parts to stick or fail and the lash can be varied to help tune the combination. Hydraulic lifters are designed to run at no lash and have a moveable pushrod seat controlled by engine oil to accomplish this. They are normally adjusted to a “preload” (how far down from zero lash) setting and use a camshaft designed for a “no lash” situation. They are basicly a set and forget lifter because of the preload typeadjustment and are normally used up to approximately 6500 rpm.Hydraulic lifters (because of thehydraulic unit) are subject to bleed down issues caused by debri
