Custom Headwork by Dave Mackie Engineering
For decades Dave Mackie Engineering (DME) headwork has been ranked with the best available anywhere. The Keith Ruxton engines in the Easyrider Harley Streamliner were running DME ported heads when it became the Worlds Fastest Motorcycle at over 322 miles per hour. Bob Taft of Rat’s Whole Place was running DME ported heads when his drag bike became the World's First 8-Second Evolution Powered Drag Bike. The list goes on to include Scores of National Records, many National Championships and Sturgis and Daytona Dyno Shootout Winners.
DME headwork has several features that make it unique in the industry. After glass beading and cleaning ports and combustion chambers we take measurements to determine the effects of foundry core shift. We then select the best program and CNC shape each port. The use of CNC equipment assures that we get we our best shape every time. When the CNC work is complete we apply the polishes and atomization finishes.
A few words about polishing. There are several conceptions about polishing ranging from “it’s magic” to “it doesn’t do a thing.” The truth lies somewhere in between. Polishing actually melts and seals the skin of the surface being polished thus forming a bit of a barrier to help retain heat in that area. At DME we polish the combustion chambers and the exhaust ports. It is desirable to keep heat in the combustion chamber because heat is power which is what we are after. We also want to keep heat in the exhaust ports because the hotter the exhaust gases are the greater the velocity they will have. Increased velocity will get the gases out faster. These benefits exist even after these areas carbon up because the underlying surfaces are still sealed.
Areas that should not, in our opinion, be polished are the intake ports and manifold. Polishing has little or no effect on flow characteristics but it can have a detrimental effect on atomization. The reason for this is that the fuel in the intake charge is heavier than the air. When the charge bends its way through the manifold and port the fuel tends to centrifuge out of the air stream and onto the port wall. When the wall has a high polish the fuel tends to cling to the wall and slides on into the combustion chamber as raw fuel. Raw fuel does not burn as well or as completely as when atomized and this can result in less power, less economy, and a “dirtier” motor. For these reasons DME creates very coarse textured, high atomization intake ports and manifolds. This coarse finish inhibits the sliding of the fuel and kicks it back into the air stream where it is then re-atomized. This can result in more power, better economy and a cleaner running engine.
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Some parts and services may not be legal on 1978 and later emission-controlled vehicles. Check your local, state and federal laws.*
*Dave Mackie Engineering high-performance headwork and camshafts are not legal in the state of California for use on 1978 and later emission-controlled vehicles.