I was just wondering what the difference was between a roller cam and a hydrolic cam? Which one is better?

 

There are three types of pushrod engine cams. Hydraulic cams use flat tappet hydraulic lifters that slide up and down the lobes as the cam spins. Hydraulic roller cams use hydraulic lifters also, but the lifters have rollers on them. Because the roller can follow the cam through more extreme ramp profiles, hydraulic rollers can produce way more power, even if the numbers were identical to a standard hydraulic cam due to more area under the curve. Solid roller cams use solid roller lifters, and can do even more radical ramps, but require more maintenance and make more noise, which is why OEM doesn't use them.

 

The fourth type is a flat tappet solid lifter cam.

Rich Krause

 

Well, OEM hasn't used solid lifter cams since the muscle car era, and even then they were rare. Roller style cams usually wear much better than a tappet style cam because the lifters roll over the cam lobes which creates less friction. Unfortunately, a roller cam setup is always more expensive as well.

 

Now, now. Don't try to make me feel that old! They weren't THAT rare in the old days. Flat tappet solid lifter cams were admittedly not found all that often on factory cars, but most of the really legendary muscle cars did use them. And they were the mainstay of aftermarket high performance until the late 80's. Many racxing classes do not allow roller cams and that's why you will see so many solid flat tappet cams in a cam catralog to this day.

Rich Krause