Regards the high oil pressure, I would be watching out for hydraulic lock.
Hydraulic Lock of the engines lubricating oil occurs as the speed of the engine raises, the oil pump then is delivering more oil volume, the extra oil can not then pass through the oil galleys and it's relief valve fast enough, with that the oil pressure suddenly spikes.
This is presented as a sudden load on the drive train that drives the oil pump and usually breaks a tooth from a gear or shears the driving pin from the shaft driving the pump.
I have seen more instances of hydraulic lock than I would wish for;
With a McCormick Farmall Super A tractor, the winding up of a hydraulic hoist relief valve so supposedly increasing the tractor's lifting capacity, resulted in the oil pump locking up breaking the valve timing gear that drove the hoist pump.
With a Massey Ferguson 194-4, the fitting by the dealer of extra remote controls to the bank resulted in decreased flow through the system and that resulted in the hydraulic pump blowing the end plate off the hoist pump. That problem was rectified by fitting another higher capacity relief valve near the pump between the inlet and outlet.
Just recently I have been given a ex army six cylinder 2.6 Land Rover engine, it had the drive gear to the oil pump and distributor broken, looking for a cause I found the oil cooler lines had been damaged, kinking the pipelines, this would have restricted the overall oil flow and then loaded the oil pump breaking that gear, it most likely could have happened when the engine was revved when the oil was cold.
At least, I suggest to ease your relief valve setting to ensure the flow is always adequate, that relief valve could have been screwed up on the worn engine to stop bearing rattle and now with work done may need resetting.
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