I can't speak with experience on the Chev oil system in a dipper engine, but my thoughts on seeing that sort of pressure in an engine that has been recently "reconditioned, assembled and painted" would give rise to suspicions that the block was not properly cleaned (ie some sludge or crud remaining in an oil gallery), or not properly assembled (ie misalignment of a feed hole in a bearing, wrong gasket covering a port).
But before you get too worried, can you get a second person to rotate the engine by hand, or even crank the engine on the starter while you "drill" the pump and observe the gauge. It could just be a tight tolerance or something needing to bed in to open up a clearance somewhere to improve flow to relieve pressure.
__________________
You can help Keep Mapleleafup Up! See Here how you can help, and why you should! 
|