hi and happy new year
Im refreshing an lq4 , nothing fancy , all stock

I checked the crankshaft;s clearances using plastic gauge and everything looked good .

now what happen is : when I torqued down the main cap , with ONLY the center bolts torqued to spec ( bolts 1 to 10 ) , i could not turned the crank by hand ?? then with the outer bolts torqued as well ( 11 to 20 ) the crank turned

I confirm the main cap are in the right position/orientation . everything is lube as well

what do you guys think about it ?

 

This is why you torque all bolts. Torquing only the center bolts distorts the caps slightly, but enough to tighten down on the crank.

 

When you torque the main caps you need to follow a sequence for the LS1/LS2 and other LS variants. You should be able to find it online. I say start over and follow the proper sequence.

 

The LS/LT main bolt torquing sequence calls for the inner 10 to be torqued before the outer 10, so Vincentnova was following the correct sequence. I’ve actually never tried to turn a crank halfway through the sequence so I cannot comment on the snug issue middle-way through, though I’m not surprised.
VN, setting thrust bearing is critical during this process, or you’ll be seeing lots of glitter in the oil as the thrust bearing gets carved away. Hopefully you used proper protocol while setting the thrust.

 

Did you align the thrust bearing after torqueing the inner bolts to 15 ft lbs? I would probably go back through the procedure again and then check thrust clearance. Should be between .0015-.0078 and if its too tight you'll need to remove some material from the thrust surface of the bearing.