COMP Cams® Performance Lifters
The lifter is one of the most critical pieces in an engine combination. Whether it be mechanical or hydraulic, flat tappet or roller, the lifter determines how the camshaft will react to the balance of the engine combination. As operating range increases, lifter and valve float become serious considerations Increased spring pressure can sometimes be the answer, but more often than not, the ability of the lifter to manage the load is the key to success or valve train failure. COMP Cams® offers all of the popular lifter designs, and COMP Cams’® CAMHELP® personnel can help with the all important lifter decision.

Early overhead valve engine designs utilized the hydraulic tappet to quiet valve train noise. High RPM was never a consideration, nor was longevity. An engine from the mid-fifties to early sixties seldom saw anywhere near 100,000 miles in its life span. Competition engines were virtually unknown, and "street" performance had not yet surfaced. Excessive oiling clearances in valve lifters, then known as "tappets" because of the noise that they made, was not even a consideration. Car builders were more concerned with controlling engine noises that engine efficiency. Solid or mechanical lifters became the tappet of choice by allowing the engine to rev higher without floating the valve train. Valve lash could be controlled or adjusted as necessary to optimize the available torque curve.

The advent of precision machining capabilities in mass production gave the aftermarket the first opportunities to build performance hydraulic lifters. Closer tolerances in metering and oil control allowed us to create a lifter that allowed more or less compression of the internal plunger in the lifter. There were two opposing schools of thought here. On one hand, a softer lifter was considered best, because it allowed the plunger to compress under sudden heavy loading, preventing binding and over-acceleration of the valve train. The othertheory was that tightened control in the lifter allowed the valve train to respond quicker. The increased volume of oil under the plunger then became a mechanical "wedge" to more closely resemble a mechanical valve train. Both assumptions were correct, and both had their place, even though they achieved totally opposite results. But, this was the beginning of fine-tuning and opened the door to better technology.

The perfection or utilization of the needle bearing gave us the practical application of the roller lifter. Cam lobe designers had for some time visualized that longer, wider ramps would allow increased performance by allowing for greater cylinder filling and better exhaust flow. Unfortunately, flat bottom lifters were forced to maintain a somewhat narrow contact patch on the camshaft or lifter failure would occur. The roller tip followed the cam profile several degrees longer, allowing the lifter to continue controlling valve motion beyond the capabilities of the flat tappet lifter. Immediate performance gains were recognized from essentially the same camshaft specifications. Radically increased performance was only a small step away. This became possible through the increased valve springs pressures that were now feasible with mechanical lifters that did not scrub the surface of the camshaft as much. Introduction of steel, rather than cast or ductile iron camshaft cores opened the door to even greater spring pressures.

Hydraulic roller progression was somewhat slower, because the hydraulic mechanism prevented excessive spring pressures and excessive ramp speeds. The thought was that hydraulic performance was of little benefit combined with a roller tip lifter. The major auto manufacturers would be the ones to change this perception. As engines began to see 150,000 to 200,000 miles, durability became a problem. The basic flat tappet cam became a weak link the modern overhead valve engine configuration. Roller cams created less friction and lasted much longer while making the engine combination more efficient. The hydraulic roller has become the final link in the evolution of the overhead valve engine that so many of us have utilized for our performance vehicles over the past 50 years. The next time you look at the long list of available options of lifter types and styles, think back and appreciate the advancement in valve train technology.

COMP Cams® lifters are identifiable by the part number directly placed on the lifter itself, insist on the best and accept no imitations.