Oil Pressure issue.... 1997 Bluebird

[lordprada]

Having just changed the timing chains etc on the car, there now appears to be an oil pressure issue...the oil lamp will not turn off....I have tested the oil pressure with a gauge and it will go to about 4psi....certainly not high enough.... I have also put in a new oil pressure switch and tested it to earth which does then turn off the light....so I know it works....the only other thing I can think of is the oil pressure releif valve on the pump? Any suggestions would be greatly appreciated.