SPECIFICATIONS BORE: 16.6mm (.65 in.) STROKE: 16mm (.63 in.) DISPLACEMENT: 3.46cc (.21ci) CARB TYPE: Slide type, aluminum body w/nylon insulator, three-needle CARB BORE: 8mm and 7mm elliptical restrictors DYNO CARB SETTINGS (AFTER BREAK-IN): HSN 2.5 turns out from seated, LSN 0.5mm out from flush, and mid-speed needle flush with carb body HEAD BUTTON: Turbo SUPPLIED GLOW PLUG: P3 Turbo PORTS: 4 PISTON/SLEEVE: ABC CRANKSHAFT TYPE: 14mm SG TIMING SPECS EXHAUST PORT HEIGHT: 6.4mm from BDC TRANSFER PORT HEIGHT: 3.5mm from BDC EXHAUST PORT TIMING: 165° TRANSFER PORT TIMING: 114° INTAKE PORT OPENING: 15.5° ABDC INTAKE PORT CLOSING: 74.5° ATDC INTAKE PORT DURATION: 239° HP: 1.50 @ 26,000rpm (peak corr. hp) TQ: 59.82 @ 25,000rpm (peak oz.-in. tq) PEAK DYNO RPM: 42,750 (peak rpm measured) LOW AVG HP: 41.17/.64 (oz.-in. tq/ corr. hp) HIGH AVG HP: 53.87/1.07 (oz.-in. tq/corr. hp) HEAD & HEAD BUTTON The cooling head of the 321B Samurai engine is a bit of a new take on an iconic design. It appears that Protek RC adopted the XZ cooling head, which sits quite low on the engine due to its being milled on the bottom to conform around the top of the case, thus lowering the whole assembly roughly 8mm. This design is very common on today’s race-type engines and brings the VZ styling up to snuff. To top it off, they went and drilled the bottom eight fins with gobs of lightening holes, further lowering the weight and CG of this engine. The head button itself is a bit anti-climactic. Though just your traditional run of the mill turbo head button, it is nicely machined and has a dome shape to lend power to the higher rpm range. 180° 270° We miss running nitro all the time. WWW.VRCMAG.COM 123
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