oil pressure 19 diesel

[rellim]

Oh boy managed to changed engine from blown 16 turbo diesel to 19 diesel but am having problem with lack of oil pressure.
Changed sump and oil pumps over on engines.
Any great words of wisdom to overcome this problem would be really helpful.
Also starter motor had a wee bang but still just manages to turn should I change it ?
Regards
rellim

[Cafnod]

How have you determined that your oil pressure is low?