cummins x15

[Running rough]

Honostly it is a nice smooth running engine, does not have electrical fan clutch but rather a hydraulic driven fan, seems like not bad design, as for oil presure runs the same as the trucks, do you serieously think even if you could up the oil presure to 60psi plus that it would benifit the bottem end bearings and crank, I think not, the way I understand the way a crank main and rod bearings safely get lubed is by an oil rifle in the crank puting a steady supply of oil between the crank jornouls and bearings, it is the turning motion of the crank and the stead oil supply the forms a tiny wedge that keeps the bearing from contacting the crank, this oil film that is created is called I believe 'hydrodynamic lubrication' and oil psi in this region is estimated to be in the thousands of psi, and has very little to do with what you oil psi gauge reads, that is more or less just a reading of resistance to flow, however increasing oil presure in regards to increasing flow the the cam bushings in the head might benifit with increasing presure, but my theory on premature cam failure in isx engines is the tiny oil gallery's in the head become chocked off with soot, thus not getting the proper oil flow to the cams, just my 2 cents, and if you want a tougher bottem end, you likely have to increase crank and journal size to take bigger diameter bearings