The Best Aluminum Roller Rockers for SBC 1.5 Ratio
Roller rockers are an effective design change over standard rockers, increasing the engine's overall efficiency and performance. Small-block Chevrolet engines, or SBCs, are some of the best-known automobile engine and include the 283, 327 and 350 cubic-inch small-block powerhouses. The intended use of your engine determines the best aluminum roller rockers for your small block Chevy engine, be it for high performance reasons, or just overall valvetrain improvement.
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Rocker Arm Function
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The engine's valvetrain consists primarily of the camshaft, pushrods, rocker arms and the individual valves. Each pushrod end rests on a camshaft lobe, and as the camshaft rotates, the pushrods move up and down, causing them to activate the rocker arms. The rocker arms then depress and release the valves, allowing fuel to enter, and exhaust to exit, the combustion chamber.
Roller Rockers Vs. Stock Rockers
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Roller rockers are designed differently than stock rockers. The report, "Stock Rocker Vs. Roller Rocker," identifies stock rockers as die-struck flat steel pieces, which inherently contain consistency flaws due to the manufacturing process, and the fact they are not designed for the high tolerances required of performance engines. Also, over time, these rockers can stress due to wear and heat issues, making them brittle and more likely to fail. Roller rockers are a smarter design, and factor in many individual performance requirements in both construction and components used, all of which produce more horsepower.
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Roller Rocker Differences
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Aluminum roller rockers, as their name implies, have friction-reducing qualities, as well as aluminum construction, transferring heat better and reducing rocker arm weight. Differences include the type of aluminum used, and whether the rocker arms are cast or billeted. Billeted rocker arms are formed from a solid piece of an aluminum bar, whereas cast rockers are made from molten aluminum poured into a mold. Also, according to Jegs Performance, a 1.5 valve ratio causes the rocker arm to move the valve 1.5 times the cam lift, or 0.6 inches, whereas higher ratios lift the rocker further. As ratios increase, more work is demanded of the rocker arm, requiring higher tolerances in its construction.
Best SBC Aluminum Roller Rockers
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Choosing the best aluminum roller rockers for your SBC is subjective, depending on the amount of performance the engine is being built for. Rocker arms are part of a chain, and need to reflect the camshaft's performance design. A 1.5 ratio is not overly extreme, so the best thing to look for is the quality of the parts, including the tolerance of the aluminum used. Billeted aluminum is stronger than cast, and 7000 to 8000-series aluminum, heat treated to the T-6 level, is about as strong as you can get. Also, look for quality steel in the components, such as a nickel-chrome-moly alloy, as quality alloys maintain the highest tolerances.
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