Roller tip vs stock rocker arm

I'd be surprised at any gain from roller tipped (not full rollers) rockers. The gain from full rollers is mostly due to the frictional loss in the trunion over the ball or sled fulcrums. And with such a small increase from roller tipped to full rollers, the tipped ones are really a waste of money. If you watch a stock rocker thru it's full travel on the valve stem (turning the crank by hand) you'll see there's not much resistence there. The tip somewhat rolls across the stem face.

There really isn't much of a gain with roller or roller tip rockers unless your motor has some serious friction issues to begin with. I like them for the "not so FREE' HP but I would imagine at higher RPM is where they might have some added benifit.
Kevin

they add valvetrain stability and reduce valve tip wear, both of which are important when you get to high lift cams and higher rpm. Any added hp is considered a bonus to me.

If by "stability" you mean less deflection, I certainly agree. They become more and more attractive as lift and spring pressure increase. On a mild flat tappet cam with soft springs, there probably isn't much of a gain anywhere.

Hot Rod did an article years ago where they dynoed after each mod. Switching to Rollers gained Zero.

CochinoFilipino said:

Hot Rod did an article years ago where they dynoed after each mod. Switching to Rollers gained Zero.

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Full rollers or roller tipped? Ford found a 15 hp gain on the 93 Cobra 5.0 in switching to the 1.7 full rollers. Some was from the increased lift, some from the stiffer rocker, a tad from the tip, then the most was from the frictional loss.

302 coupe said:

they add valvetrain stability and reduce valve tip wear, both of which are important when you get to high lift cams and higher rpm. Any added hp is considered a bonus to me.

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You are right on the money there. They aren't very expensive, and if you were already going to replace the stockers it's nice peace of mind. But, don't do it for a performance gain, you'll be dissapointed.

D.Hearne said:

Full rollers or roller tipped? Ford found a 15 hp gain on the 93 Cobra 5.0 in switching to the 1.7 full rollers. Some was from the increased lift, some from the stiffer rocker, a tad from the tip, then the most was from the frictional loss.

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Full rollers. I'd bet that all 15hp came from the 1.7 ratio.

You'll get some from the increased lift in the ratio switch, but a .030 gain in lift ain't a whole lot. The frictional loss and rev potential is where most is found.