The first roller cam and lifter were invented back in 1893 by Dr. Rudolf Diesel, for his experimental engine that had a clevis-type cam. Since the days of the Model T, roller cams and tappets have been perfected by racing enthusiasts and are now more popular than ever.
Valve lifts and acceleration rates of the cam lobe are far greater with a roller cam and lifter than with a flat tappet design. With newer technology, roller cams and lifters are now broken down into two varieties.
From a design standpoint, the roller tappet has an infinite base diameter. A roller cam profile cannot be used with a flat tappet, as the velocity is too high without causing flat tappet lifter failure.
Erson Cams offers both solid and hydraulic roller designs, and they’re here to help us explain the difference.
Hydraulic Roller Cams and Lifters
Hydraulic lifters use a pressurized cylinder and piston to maintain a zero-gap valvetrain. The hydraulic roller lifters combine the performance characteristics of a solid roller cam with the reliability of a hydraulic cam.
Mechanical roller lifters offer higher lift, duration, and overall cam profiles for all-out racing applications. Hydraulic roller lifters have a hydraulic reservoir that offers advantages but limits the maximum cam lobe profile.
Another important advantage is that hydraulic roller cams require no break-in period — this eliminates any possibility of premature camshaft and lifter failure due to improper break-ins.
There are a few limits to using a hydraulic roller valvetrain. The first is the initial cost, which is noticeably higher due to the types of materials needed to withstand the higher loads. Also, a hydraulic roller lifter is heavier than the solid option, so they have more inertia for the valve springs to overcome.
Mechanical-Solid Roller Cams And Lifters
One of the advantages of a solid roller cam is its ability to provide greater lift and duration profiles for all-out performance and racing. For example, an Erson cam for a big-block Chevrolet application will have maximum measurements for a hydraulic roller setup of .621-inches lift, and a maximum duration of .322-inches intake./330-inches exhaust.
This Erson cam profile says it’s best for Pro Street and e.t. bracket racing applications for 540-632 cubic inch engines — no less than 10.5:1 compression, aftermarket heads, with at least 850 cfm carburetor.
Erson offers 60 solid roller cam profiles with larger lift and duration than hydraulic roller…
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