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#1
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Let's say I have a torque motor and......
To anyone with experience using roller rocker arms. What, if any, would be the benefit of using 1.5 ratio ROLLER rockers on a BB 440 torque engine vs. STAMPED steel rockers.
Valve springs have an open pressure of 300 lbs. cam has a .470"I / .504"E lift. Engine is rarely rev'd to 4000 rpm. Any thoughts... |
#2
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In a race motor I would say go with a roller because the tolerances are more accurate, and when you are running very high lift cams with close valve to piston clearances you can't be off. Also from a blueprinting standpoint you want all the cylinders to be equal. Factory stamped steel ones can vary from 1.45 to 1.55 and at high RPM's flex more and throw off the #'s. If you to measure the max lift of your cam on each spring retainer you will see the differences.
Picture this, your intake lift at the cam is around .3133 from the specs you gave. Multiply that by 1.5 rockers and you get your .470 lift at the valve. now take .313 and multiply it by 1.45. You get only .454 lift at the valve! Or the other way around take .313 and multiply it by 1.55 and you get .485 lift. So you can see how in a race motor this is unacceptable. These also are worst case scenerios. In a stock rebuild or mild street motor it's not that big a deal though. I would save the money and use it elsewhere. I have the crane cam ductile rockers in my street/strip 340 so the accuracy is there. There is also the friction thing that is a plus but that is not as important as the rest of the stuff I talked about. Be careful of the cheap rollers out there, I wouldn't put some of them on my lawnmower. Hope I helped. |
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