07/14/2026
Tech Tuesday | Internal vs. External Balancing
Factory Powerstroke engines are externally balanced, meaning part of the engineâs balance weight lives in the harmonic damper and flexplate. Thatâs perfectly acceptable for a stock engine, but as horsepower and RPM increase, those external weights create additional loads on the crankshaftâespecially the crank snout.
Every Kill Devil Diesel engine starts with a brand-new Genuine Ford crankshaft. We donât build engines around worn, previously stressed components.
For customers building high-RPM race enginesâtypically in the 5,000-6,000+ RPM rangeâwe offer optional internal balancing. On this 6.7L Powerstroke, we installed 1,600 grams of Mallory heavy metalâ800 grams in the front counterweights and 800 grams in the rearâto convert the engine to a true neutral internal balance, meanjng all of the weight is in tbe counterwights of thr crankshaft, and the flexplate and dampener are nuetral, no extra weights. Itâs a process that requires hours of precision machining and a significant investment in materials, but the results speak for themselves.
The payoff is a smoother, stronger, and more stable rotating assembly with reduced stress on the crankshaft, bearings, and engine block at elevated RPM.
These engines are also paired with a neutral-balance fluid damper and neutral-balance billet flexplate, and every KDD 6.7 crankshaft has the crank gear TIG welded for maximum reliability.
These are the details youâll never see once the engine is assembledâbut theyâre exactly what separates a good engine from one engineered to survive at the highest level.
The Devilâs in the Details