recon engine limited oil pressure

[dillorto]

Hi,I have just rebuilt my 1098 engine (twice)and cant get proper oil pressure,180psi compression on all 4,new dig end and main bearing shells 2 new oil pumps,new relief valve,new unleaded head,but still only getting 40psi which when you turn off the engine drops immedietly to zero,in fact last time I tried it it actually seized at mid revs but I managed to get it eased off again.I,m totally stumped any ideas will be much appreciated.thanks

[PSL184]

Have you primed the oil pump first?

[bmcecosse]

If it's making any pressure - it's pumping.... Why two oil pumps?? Must be something seriously wrong - what do you mean 'seized' ?? You will need to get the sump off and inspect it all. The only mains cap that could be wrong way round is the centre one - is it right way round? And then the big ends - are they all on the correct rods - and right way round? I assume you have inspected the relief valve and checked there's no swarf sitting across the seat. Also - is the pickup pipe fitted ok - fully tightened?? Likely it's going to need a reground crank..........

[dillorto]

2 oil pumps because I though the first one was faulty,i have checked all your suggestions except the centre bearing,the seizing element came when I revved her up and she just ground to a halt but not solid so I got her eased off again,.you could be right crank regrind is the only thing that might cure it,to be honest im so teed off with it I might just phone bull motif for a bottom end!!!!!!could a cracked block cause this problem,Thanks all

[bmcecosse]

Never actually heard of a cracked block....

[dillorto]

thanks for all the advice guys,i think I will drop the sump and double check the centre crank bearing,thats the only thing that seems to ring alarm bells.cheers

[mike.perry]

Piston Compression will have no effect on oil pressure.
Is the oil pressure steady at 40lbs when running? What is the tick over pressure? Is the gauge correct?
Are you sure that you fitted the correct size shells?