Atomic Vernier Adjustable Sprocket Kit – #306560-PR

The VCT sprockets in the Barra engine can become problematic over time due to wear and tear on the mechanism. Additionally, performance modifications such as changes to valvespring pressure, oil pressure, and rev limiters can disrupt the factory sprocket’s operation, leading to tuning issues and fault code logging.

Proficient tuners understand that precise cam phasing is essential for maximizing engine power. To address this, Atomic designed and manufactured adjustable cam sprockets, enabling tuners to optimize the volumetric efficiency (VE) of their engine combinations. Our vernier sprockets also eliminate the need to retain the original Ford ECU and harness when transplanting a Barra engine into other vehicles. This is particularly beneficial since few aftermarket ECUs can effectively control the variable cam function, opening up numerous possibilities for retrofitting the DOHC engine into earlier vehicles.

The fourth iteration of Atomic’s vernier sprockets (circa 2022) is CNC machined from 4140 chrome moly steel, with the outer section gas nitrided for maximum durability. The hub is made from high-tensile 6061 T-6 heat-treated alloy and anodized for an attractive appearance. The kit includes a custom-made 30mm diameter Belleville style washer to ensure maximum clamping force by the M10 camshaft bolt (also supplied).

Secured together by six high-tensile flange head bolts, the sprockets feature degreed markings on the hub, making timing adjustments straightforward. With a full 24 degrees of movement available, professional engine builders have a wide range of adjustment options.