roller rockers?

well, the engine has been rebuilt by the looks of it, so i dont want to have to mess with taking it apart. The heads on the other hand look as though they could use some touching up, and why not just get new rockers as well. Ok, well thank you all for the info, and i will try some of this stuff out that you guys said.

 

what kind of hp will you gain on a stock internal motor with roller rockers witch is best 1.6 or 1.7

 

ads claim that 1.7 roller rockers get you 15 hp.

 

Can/should they be used on stock studs?

 

I have read that the roller portion of the roller rocker ALONE gets you an extra 15 hp just from less friction at the roller tip and the roller fulcrum.

I think you may get a bit more from the extra lift.

 

lets say my motor has been rebuilt to stock specifications excluding the new cam the guy put in it. With putting new rockers on, i will gain an extra set amount of hp right?

 

If I am correct about the 15 hp from just the roller bearings in the tips and fulcrum, and your heads are not restricting flow and can handle a little more, then yes, you could expect approx 30 extra horses, depending of course, on the cam grind. 15 for the rollers, and then an extra 10-20 for the extra lift you are getting.

Could be more, could be less, depending how what your intake, heads, and cam grind are and how much you started with.

 

Okay, I understand what you are saying Bryant, but there are too many unknowns with his combination. If he had a stock short block, I would say he is probably okay to "just install them". But he has an unknown cam, unknown rotating assembly and unknown valve springs. Also, even if it rotates freely manually, that is with a cold engine and no engine harmonics. What looks good at 5 rpm can be bouncing off the other parts at 3500 rpm.

Piston expansion, valve train harmonics, valve spring pressures, valve spring installed height vs. compressed height, etc. all come into play.

i.e. I bought a cam that has short duration but a lot of lift which helps with low rpm torque. The cam has .530 lift at 1.6 ratio. The valve springs were fine as far as the pressures were concerned but had a max of .490 before coil bind. So I had to replace the springs. The new springs allow .550 lift. But if I were to add 1.7 rockers, I would be causing valve spring coil bind which has a tendency to bend or break parts.

The cam is a Baja Beast cam from Crower.

Since we don't know what cam the PO put into this motor, I would not recommend adding the 1.7 rockers.

 

i found a nice set of 1.6's for a reasonable price. i might look into buying them down the road sometime.