Toyota Repair: 1992 Toyota pickup motor camshaft, camshaft lobes, camshaft bearings

Question
Hey, I have a 92 toyota pickup with a 22re motor 4x4.  i had the motor rebuilt by a machine shop in town.  and when i brought it in i bent a piston rod and the camshaft lobes were worn bad.   they bored the motor.20 over and new pistons rods everything new besides the head.  i drove it for 500 miles had a noise.  broght it back on 2 cylinders the camshaft was worn bad with the rocker arms as well.   put new cam and rocker arms.  50 miles later had a nock. pulled the valve cover and at cylinder #2 the camshaft lobe is worn really bad.  brought it back and they are not sure.   you should know both times i pulled and installed the motor.  first time i started to crank it i had the distributor in 180 out.  started it for a while and had good oil presure with out running the motor.  it took a while for the oil pressure to build up but got it and then realized it wouldnt start.  fixed the distributor and ran it fine with no noise as i said above.  then second time i disabled the fuel pump and distributor and coil.  like i did the first time .  no oil pressure.  i called him in the morning and he said he didnt pull the timing cover off and tried to prime the oil pump as best he could, told me to go ahead and start the motor.  i did and the oil pressure built right up quick.  ok   
so am i wearing out the camshaft on start or is there something wrong with the head.  remember when i brought it in it had worn lobes on the camshaft.  
when  i brought it back after the original rebuild he pulled the whole motor down and checked the bottom end and he said it was all within spec.  so assume just top end.  i have this problem now.  what do you think.

Answer
Anytime there is excessive wear on engine parts it is usually due to a lack of lubrication.
The camshaft bearings are lubricated through oil passages in the cam bearing journals but the problem seems to be that the cam lobes and the rocker arm contact surfaces are wearing excessively, the rocker arms are lubricated through oil passages in the rocker arm shafts, there is a possibility that some of these oil holes in the rocker arm shafts are blocked or clogged possibly with metal particles from when the engine disintegrated the first time, remove the rocker arm assemblies and disassemble them and make sure all the oil holes in the shafts are clear, also make sure that the oil holes are lined up correctly with the rocker arms.