1995 Nissan Patrol/Safari

1995 Nissan Patrol/Safari 6 cyl

Hi,
I have done a re ring on my sisters 95 patrol GQ ute, I did this with the engine still in the vehicle. I used the old main bearings on the conrods but didnt remove crank so bearings stayed same on big end. Crank spun freely before I put the pistons in. I put the pistons back in one by one, turning crank in the process, by the time I got to the 4th piston the crank became very hard to turn, although I was able to turn it with a massive bar to put the last two pistons in, when I torqued the conrods back on to crank shaft they were wiped clean but I did not put any lube on them, now the engine is back together I can not get the engine to turn over. Is this because the bearings have spun or is there an easy way to fix this problem.