the oil pump didnt fail the mechanic over in japan who put the engine together was the one who failed
after we pulled the engine out to repair the problem we noticed the oil pump was already upgrade with a CNC machined billet item
the backing plate which bolts onto the oil pump was lose, the bolts were all lose so this was the cause of the drop in oil pressure
we then pulled of the sump to inspect the bottom end bearings and noticed all the bottom end bearings were brand new and in perfect condition
we also noticed the crank was replaced with a R33 crank shaft as well