CALLIES DURASTAR STAGE 1 Alternate Firing Camshaft.

* Key wave has a cut in on it

The OEM firing order ends with cylinder 3 and begins with cylinders 1 and 2. The result is a 3-1-2 hit to the crankshaft. Duramax cranks have a tendency to break right behind the first rod throw at the intersection of the second main journal, right where the 3-1-2 hit would stress the crankshaft the most.

The Callies Alternative Firing Camshaft changes the firing order so it begins on cylinder 1 and ends on cylinders 7 than 8. This eliminates the over stress on the crank.

Callies fully finished camshafts are machined and heat treated entirely in house. This continuity of manufacturing allows Callies to deliver high quality camshafts on schedule. Our finished cams are ground with the latest Landis CNC technology. They are ADCOLE and Jenoptik inspected for accuracy, making them the most consistent cams on the market today. If required, your cams can be finished with inverted flank lobe profiles and complex VVT oil channels and drillings.

Callies Cam Research Lab – Valvetrain durability is a key ingredient to the success of every engine. The Callies Cam Research Lab has been established to guarantee that our cams are capable of extended life cycles in abusive applications. When combined with our metallurgical capabilities, the Callies Cam Research Lab allows evaluation of lobe profiles, valvetrain systems and processing methods like no other cam company.

Spintron testing enables our engineering staff to evaluate valvetrain stability in minute detail up to 11,000 RPM. Programmable test cycles allow complete event simulation. Sixteen channel data acquisition can provide monitoring of temperatures, pressures, flows, loads and strain. Let Callies help you design your next step forward.

Carburized & Hardened 8620 steel camshaft cores are produced to AMS 2301 (AQ) standards. Carbocore cams are machined and heat treated entirely in house.