Could someone please explain the difference in the types of cams, like a hydraulic, flat tappet, roller, etc. I've got a 1992 z28 with the l98 engine. What type do I have in my car? If you have a roller cam does this mean it has the roller lifters?

 

You do have a hydraulic roller (87+ I believe). You also have hydraulic rollers.

Hyrdualic vs. Flat Tappet:

Think of a bicycle. Lock up the rear wheel and push it. It slides across and causes a lot of friction right? Now let off the brake it moves nice and easy. That's all there is to it: Less friction.

 

The type of cam is based on the lifters. There are 2 major aspects of lifter construction - tappet style and body style.

The tappet is the surface that rides on the cam....they are either flat or roller. Rollers roll on the cam while flats slide across it. Rollers are more efficient (less friction) and more expensive, and can handle faster opening/closing rates (steeper lobes on the cam) which translates into more airflow into the chamber.

The body is either solid or hydraulic. Solid lifters are just that...solid. They actuate the valve in precise time with the cam, which allows more precise cam timing and provides a more aggressive opening rate. Hydraulic lifters are hollow and "pump up" with fluid, and the hydraulic pressure that this creates allows a sort of margin for error on the valve lash, as well as lubricatign the rockers. Hydraulic lifters compensate for changing engine conditions, such as thermal expansion and component wear, solids don't. Solid lifters need to be readjusted regularly, hydraulics don't.



Your car has a hydraulic roller cam and lifters, which is the best setup for a street car.