In 2001, we introduced the Scotsman Series cylinder heads to the Harley-Davidson market. These heads were featured in many magazines and became the industry leader in budget cylinder head porting services. Over the past 10 years, we have been improving these head designs with continuous changes that have all been tried and proven. The most drastic change was when we acquired a NEWEN Contour-BB cylinder head machine. With this advanced equipment, it became possible to perform CNC-machined profiles on valve seats, which have become a performance standard in the racing industry. Short Block Charlie now works with NEWEN, traveling the globe to train machine operators and service the machinery. He consults with cylinder head engineers from Formula 1, NASCAR, NHRA, and major motorcycle race teams to assist them in designing sophisticated valve seat profiles.
Over the past few months, we have spent a lot of time in our R&D department developing the 1.980 Scotsman cylinder head. SBC’s goal is to raise the standard in the Harley market once again.
How We Did It
After working with AV&V, new intake valves were developed that had a diameter of 1.980. Over the years, valve diameters of 1.900, 1.940, and 2.000 have been tried. The 1.900 and 1.940 gradually became the industry standard. It was found that 2.000 diameter valves were too large for the 95”, 96”, 103”, and 107” engines.
Designing the 1.980 intake was where most of our time was spent on this project. In order to do this, we machined and designed over 50 diverse valve seat profiles for the intake seats. The goal was to garner maximum airflow throughout the port between .050 and .600 lift. We achieved this by taking a 2006 Twin Cam head and replacing the intake seats and trying different seat profiles. Then each head was flow tested and the results were documented. The intake port was not ported until we found the best profile. Among the seat profiles tested were raised seats, multi-angle, and radius designs. Our main objectives with a specified design were to get over 350 cfm’s of airflow and maximum port velocity. We achieved both.
We took a look at the past success of the Scotsman Series head and what our customers wanted. Feedback from customers led to our current setup, which utilizes 7mm valves, bee-hive valve springs, and umbrella valve guide seals. These minute improvements have reduced valve train noise. To finish with our work on these heads, we provide either manual or electric compression release machining services at no extra charge.
SBC has once again raised the bar in the Harley-Davidson cylinder head industry.