06-22-2009, 11:08 AM
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Half-Ass Member
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Join Date: Jun 2005
Cobra Make, Engine: ERA #732, 428FE (447 CID), TKO600, Solid Flat Tappet Cam, Tons of Aluminum
Posts: 22,005
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Not Ranked
Quote:
Originally Posted by Chaplin
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OK, I read it, and after I read it, remembered it from the first time I read it (it's copied below for everyone's convenience). I think I would tend to agree that rollers are better than non-rollers if, and only if, they have conquered the limited lifespan and distributor gear issue. You know as well as I that you can get a ridiculous amount of power out of a solid flat tappet cam in an FE. If we just skip over the "I'm afraid to break the cam in" issue then the increased potential power from a roller would have to be such that it offsets the limited lifespan/distributor gear issue (if those issues still exist). Would you agree with that?
Quote:
I don't know if I agree with that. Because of the cam lobe profiles of a roller cam are much more aggressive and open and close the valves faster (whether solid or hyd roller) than a flat tappet cam, you will get better performance from a roller than you will from a flat tappet cam with similar or even slightly greater duration. The aggressive lobe shape of the roller cam effectively opens and closes the valves faster (as compared to a flat tappet cam) which allows the valves to stay open longer, thereby creating more "area under the curve" which provides the cylinders more time to fill at any given duration as compared to a flat tappet cam with the same duration. Or put another way, you can run a smaller duration roller cam (which means better throttle response and better idle quality, i.e., more streetable) but still have as much if not more power than you could get out of a flat tappet cam of the same duration or even slightly larger duration.
IMO, hyd roller is the way to go for a street cruiser. You eliminate the break-in problems associated with flat tappets, don't have to worry about roller bearings in solid rollers, and because of the cam lobe profiles, can run a smaller cam with better street manners without sacrificing performance of a larger flat tappet. Needless to say, I am having one installed in my motor as we speak.
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