Harley-Davidson Milwaukee-Eight Engine

My observation, is that Harley is returning to the single cam, concept, as they used to use on the pre-Twin Cam Era, i.e. EVO, Shovelhead, Panhead, engines. They have eliminated the inboard roller chain drive (inside the cam support plate), and have an easy to access, outboard roller chain drive. That is a positive development.

However, the con on this is that they have retained the pesky, PLASTIC cam chain tensioner, which is a wear item, and has to be periodically inspected and replaced or risk cratering the engine.  With the increase in power and displacement, it is going to be putting a lot more power demand on the single roller chain drive, which has a propensity to stretch over time and can negatively affect cam/valve timing. I wonder if this added power demand, will wear out the cam chain tensioner, sooner, rather, than later. It remains to be seen. I wonder if they have retained a pressed-together crankshaft which can twist out of true, as they have been known to do, on the Twin Cam engines, on a hit or miss, basis, and can crater the engine, or if they have a bolted together, stronger crankshaft, as on the pre-Twin Cam  Era, engines, which is a superior design. (more…)