Drag Illustrated Issue 139, December 2018 | Page 74

DI TECH to a keyway. Not cutting as deeply into the post also maintains its strength and integrity better directly where it is needed on the post. And the flip side of that is not losing the material that is machined out for the depth of the keyway. In fact, the post on a splined crankshaft is bigger than those without splines. So along with being stronger in design, the added post material provides even more strength over using the key method. In effect, the bonus to using a splined crank- shaft is threefold. One is using the surface area to disperse the load of the blower drive pulley. Two, a stronger post to also support that critical load point. And three, the weight of the crankshaft (and resulting rotating mass) is kept to a mini- mum while strength is not compromised. And 74 | D r a g I l l u s t r a t e d | DragIllustrated.com any help the post gets in being stronger and living longer translates to the crankshaft doing the same. All these factors combine so the spline will out- live the crankshaft in these typical bigger blower applications. That’s because in the example of a Top Fuel engine, the crankshaft will be removed from service due to torsional fatigue before the splines show cause for concern. What little differences there are between splined and non-splined crankshafts comes down to only the post itself. For one, the post diameter is increased .175 inch for the equivalent of the big-block Mopar, the standard size in those bigger blower configurations. Crankshafts with splined posts require using specific accessory components that vary by application. These would be the pulleys used on the crankshafts, insuring mat- ing splines and sizes are used. It’s more about matching the blower drive components to the spline and vice versa. Nothing else changes when using a splined crankshaft. The crank timing gear is still installed and removed the normal way. The balancer also is installed/removed the usual way. The same timing chain covers are still applicable. Staying ahead of weak links, all Callies splined post crankshafts are manufactured from billet steel. Splines are not found on forged cranks, as forgings don’t have sufficient material on the front end and post where splines are machined. Cal- lies uses 100 percent quality-certified American steel on their Ultra Billet splined crankshafts, available in a variety of strokes. Using the billet option also allows the opportunity to select from a wider variety of materials, further fine tuning each engine’s application. Using a splined crankshaft also allows racers to “strengthen’ their engines even if they aren’t running the higher volume superchargers. This can add reliability and product longevity to their engines. In short, if you can run an engine com- petitively with less stress, stronger parts and as- semblies should last longer. Down the line, as engines not using the higher volume superchargers evolve, they, too, may need the safety and reliability of a splined crankshaft. For engine shops, it will be an easy upsell. Include a stronger, splined crank in a build and a racer won’t need to worry about a shorter life of their crank due to the pulley connection. Most racers will buy into stronger and longer wearing in a heartbeat and those on the edge of needing a splined drive will smartly make the jump. - BY JOHN CAROLLO Issue 139