DYNO _Protek RC Samurai 321B 124 WWW.VRCMAG.COM Fuel injection? We need you. Let’s face it: these engines aren’t getting any easier to break in as technology evolves, and the Protek RC 321B is definitely no different. With pinch aplenty, it took some time with the heat gun to get this ready to pop to life. Carb settings were quite a way off on the rich side and took some tweaking to get the mixture to the point where the engine would fire, primarily the low speed, which was about 1½ turns too rich to start with. Once it was running, I idled two tanks of fuel through the engine while also keeping a close eye on the case temps; I never allowed the engine temp to drop below 190˚F. After each tankful, I lowered the piston to bottom dead center and allowed the engine to cool to ambient room temp before starting the process again. The third and fourth tanks were leaned slightly and alternated between long idle periods and soft, smooth runups in the rpm range to clear the engine of accumulated fuel/oil. During this process, I like to try and keep the engine in the temp range where it will be spending most of its life; in this case, that is approximately 230°F and, again, between each tank I allow the engine to cool to ambient room temp before proceeding. A couple hours of fiddling later, we were finally ready to start leaning on the needles and making some full-throttle, full-power runs. I immediately noticed that this engine is really smooth and doesn’t have many bad habits, or dips and lulls in the power, either on the front side of the curve or the back. Even when a bit over-rich, the engine still pulled well from the lower rpm all the way up to max revs, and although this may result in slightly lower output figures, it will still be plenty runnable on the track. After some additional attention to mixtures, this little gem really started to come to life, and what impressed me the most about this engine was the smoothness of the curve on the front side, but more important, the breadth of the power way out into the over-rev range. It simply continued to make power way past its torque peak all the way into the stratosphere of rpm. All said and done, the Protek RC 321B Samurai engine produced an impressive 1.50hp @ 26,000rpm and a peak torque of 59.82 oz.-in. at 25,000rpm. It topped the rev range at around 42,750rpm. PERFORMANCE
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