Brief history: 1986 FJ60 with 2F. I pulled the engine head off because 34K after a full rebuild it was still using oil. I thought it was valve guides. I made arrangement with Jim C. to exchange for an engine head that he built up with bigger valves, .050 decking, some polishing. When I got inside the engine, the #5 piston was scrubbing the cylinder wall orf #5 and #s 6 and 2 were starting. So, I pulled the rest of the engine and took it to a machine shop. They bored it out, installed a new cam, timing gear set, pistons, rings, crank bearings. They did not turn crank; said it looked OK. They did "polish" the crank. They assembled the engine and put the Jim C. head on for me. They bench tested the engine and it had oil pressure when cold (did not actually run it but had some kind of machine). I installed the engine with much travail.
Now installed, the engine runs great but when it gets up to temperature, the oil pressure drops dramatically at low rpms. I noticed this on my second trip to town (less that 100 miles on engine). My Toyota OEM gauge had never done this before. I tried to get a local mechanic to hook up his mechanical gauge but all that was accomplished was for him to reattach the oil pressure gauge wire to the ground tab and subsequently fry the dashboard unit.
So, I buy an el cheapo mechanical gauge at NAPA and install it for diagnostics. Same deal, good pressure cold or hot at high RPMs (50-60lbs) but low pressure at low RPMs (500-600) once it warms up. By low, I am talking 15-20 lbs if you believe the NAPA POS.
I am suspecting too much clearance in crank bearings but don't know much about this. WHat to do? Nothing? New Oil Pump? Tear down again? Increase Oil Weight? I do plan to get my OEM gauge fixed no matter what.
Now installed, the engine runs great but when it gets up to temperature, the oil pressure drops dramatically at low rpms. I noticed this on my second trip to town (less that 100 miles on engine). My Toyota OEM gauge had never done this before. I tried to get a local mechanic to hook up his mechanical gauge but all that was accomplished was for him to reattach the oil pressure gauge wire to the ground tab and subsequently fry the dashboard unit.
So, I buy an el cheapo mechanical gauge at NAPA and install it for diagnostics. Same deal, good pressure cold or hot at high RPMs (50-60lbs) but low pressure at low RPMs (500-600) once it warms up. By low, I am talking 15-20 lbs if you believe the NAPA POS.
I am suspecting too much clearance in crank bearings but don't know much about this. WHat to do? Nothing? New Oil Pump? Tear down again? Increase Oil Weight? I do plan to get my OEM gauge fixed no matter what.