One of the challenges to manufacturing a quality cast crankshaft, according to SCAT [1] Crankshafts owner Tom Lieb, is ensuring that the engine builder is balancing it properly according to the rest of the components which make up the rotating assembly. Making the process more challenging is when limited-engine racing series such as the IMCA put claimer-style rules in place which specify cast crankshafts must be used.
[2]SCAT has responded to this demand with the manufacture of their 9000 Series cast crankshafts, which have been manufactured to meet Lieb’s stringent design specifications and support these engine builders with a product that can meet their requirements without breaking the bank.
“A standard cast crank, from a balance standpoint, uses standard components, which are heavy. But these engine builders are using lightweight components,” says Lieb.
“One of the things we’ve done for this year is manufacture lightweight [cast] crankshafts with the counterweights machined in a position where they will support the balancing of the crankshaft with bobweights between 1630 and 1675 grams. With the standard crank, the bobweights are set up between 1800 and 1820 grams. By repositioning the counterweights, we take the weight out of the crank and make it much easier for the customer to balance it. We also moved the counterweights to the proper position so that the crank doesn’t flex the way it would if you removed the weight from the heavier crank.”
Since these features are baked right into the crankshaft’s design, the cost to the end user is far less than if they asked their engine builder to modify an existing crankshaft to meet these design criteria.