The purpose of the SoCal diesel Duramax billet main cap set is to increases block rigidity and tensional stiffness. We highly recommend using billet mains in all big power Duramax engine builds. For even added protection, add a SoCal engine girdle.
OEM main caps tend to collapse in on themselves when subjected to high horsepower. As the cap collapses, the dimension across the parting line becomes smaller, eventually causing the edge of the bearing to begin scraping oil off the crankshaft, leading to bearing and crank failure.
SoCal Diesel main caps solve the collapse issue by using high strength aircraft quality steel. Blanchard ground, precision machined. Recommended for engines above 800 RWHP.
Each SoCal Diesel main cap is drilled and tapped with an M8 x 1.25mm hole for ease of removal from the block using a slidehammer. SoCal Diesel's rear main cap is machined for a 360 degree thrust bearing, stock only uses 180 degree on the front portion of the rear main cap.
Hint: Be sure to order an extra set of thrust bearings to take advantage of this feature. A normal thrust kit only contains 3 bearings.