tappet vs roller cam?

[coreyc]

What is the difference between a tappet cam and a roller cam? Is a roller cam the same as a hydraulic cam? Is one better then the other and Why?

Thanks,
Corey C

[Mustang Boy]

a roller cam is better than a tappett cam because it frees up some of the friction and roller cams tend to be more radical because the roller aloows them to be

[Excaliber]

Unless you get really MODERN roller lifters with pressure feed oiling a standard roller lifter will not last long and is NOT recommended for street use. Standard flat tappet cam is always cheaper and unless your looking for max horse power at HIGH rpm is more than adequate.

Some folks like the hydraulic roller lifter tappets because they DO get pressure fed oil to the lifters roller. So they last much longer than standard solid rollers.

I had a solid roller, it went within a few thousand miles. I replaced it with a flat tappet cam to reduce max rpm, make the engine live longer and STILL provide plenty horse power at a nice price.

Roller cam profiles generally require pretty high valve spring pressures, not neccessarily a good thing.

[JAM1775]

I hope I do not confuse myself here ! When I switched from flat tappet to roller on my 351W I was advised the roller cam would allow me to get a bit more radical specs within the given cam's power band to 6000-6200rpm with less compromise. I went from .520 to .576 lift and actually dropped 100rpm at idle . Also, I was advised the roller cam reduced friction allowing the motor to rev smoother, faster and last longer.
Of course, making the swap did cost about $450 because my 351W needed the spider plate across the oil valley to better secure the new roller lifters plus new roller lifters, rockers and cam. Some newer blocks may not require the spider plate install. My decison was made during a rebuild so rollers/heads/cam/lifters were already a given as a required expense.
If I had a great running flat tappet set up with roller rockers only and simply wanted a bigger/better cam I'd probably just invest $100 for a better flat tappet cam and slide it in. Or consider going up in rockers (if you have clearance) from 1.6 to 1.7 ratio. Otherwise, from the ground up I never regretted going to a full roller cam set up and would do it again.

[mikiec]

I'm running a 92 302 H.O. block. This motor came with a hyd. Roller cam and lifters. I stayed with that setup when I installed a new and bigger cam. Figured, if it was good enough for ford why should I argue. That was 5 years and 38,500 miles ago.

Mike

[Excaliber]

Modern motors, such as the Ford 302 and others that come with factory hydraulic rollers are a good to go.

Adapting an older block designed before rollers became standard issue are considerably more risky to get it right. Many early 427 blocks only accept solid lifters, if you use solid ROLLER lifters you can expect a shortened life for the rollers.

[Carnut427]

Originally Posted by Excaliber

...if you use solid ROLLER lifters you can expect a shortened life for the rollers.

This is the key, solid rollers vs hydraulic rollers. Hydraulic rollers work fine even in older engines assuming they can run hydraulics. The solid roller lifters evidently get beat up because of the lash. Crower makes HIPPO solid rollers, which force feed oil to the rollers, but again the engine has to be able to run hydraulics, as that's where the oil for the rollers comes from. Other companies also make pressure-fed solid rollers, and if you want a solid roller cam, these are the only ones besides some ultra-expensive types that will last on a street car; that's why most run hydraulic rollers.

Dan