roller cam friction loss

Does anyone have numbers on horse power differance to turn a roller cam vs. a flat tappit. At one time I had an artical which checked a roller follower and a standard 2.3 Ford head, 28hp droped to 17 in the roller head at a given rpm.

 

The only differnce between the '84 & '85 Mustang 5.0 engines was the '85 had a roller cam, best I recall the 85 is rated 10HP higher. Probably be easy to look up.

 

In the same-but-different category is roller rocker arms. Many aftermarket shaft rockers, such as FE Ford, use plain bushings on the shaft and roller tips. When Chevy was redesigning their small block, the engineers chose needle bearing trunions and a plain tip.

jack vines

 

Don't worry, you'll find that friction. Just don't stop looking.

 

It isn't just friction reduction that gives a roller cam engine a power increase. A roller with the same duration opens and closes the valve quicker so the actual open valve time is greater.

 

Somewhere in the dim corners of my mind I seem to remember someone experimenting with replacing the standard type of cam bearings with needle bearings. Seems like it was Bruce Crower but I could be wrong about that. Anyway to make a long story even longer he discontinued the test due to no significant increase in horsepower on the dyno.

 

'84 Mustang GT was rated 175hp. '85 Mustang GT was rated at 210 hp.

"The four-barrel 5.0L V-8 was upgraded for 1985. Ford added 35 additional HP for the 1985 GT 4V 5.0L - pushing it up to 210 horsepower. A number of enhancements were made to the 302 HO (still topped by the 600 cfm Holley 4V with dual snorkel 460 air cleaner) including the addition of a hydraulic roller lifter camshaft, stainless steel tubular exhaust manifolds and forged 8.4:1 pistons (replacing sandcast pistons) with thinner, lightweight rings to further reduce friction. Of course, these changes necessitated a revised block and heads to accept the taller roller lifters. Exhaust restriction was reduced by splitting the exhaust pipe behind the catalytic converter and adding dual mufflers and tailpipes. "

 

yes it was the Crower Imperial cam
and it did add HP

 

While it is possible for a roller cam to do as you described, it requires a lobe profile that isn't commonly used.


The answer to your question is going to vary with the particulars of the valvetrain and the cam profiles. Friction reduction is enough that even on stock engines manufacturers are willing to spend the extra money for roller valvetrain to get a mileage improvement.