Okay here is my problem. I bought forged pistons/ rods for my motor…It’s a JDM Dohc ZC. The pistons are standard bore. I installed new rod bearings, new main bearings, new thrust washer. Basically new internals. I did not bore or hone the motor. Now when everything is put back together and I try to turn the crank by hand its turns normal then whenever any 2 pistons for example: #1 and #3 are at TDC it get real hard to turn. I have the head on but the timing belt is not on. So besides the obvious question of what is the problem. I have a few more questions 1. Will it prevent the engine from starting? 2. Will it go away or get worse. Also my friend told me that when the motor ages the bottom gets cupped sorta like “U” is there any truth to this…I took my time and was carefull

 

do you have the cams in the head? if not all the valves would be closed and there would be no way for the cylinders to release compression.

 

Are you sure you don't have a rod bearing turned around in the wrong direction. Are the rod bolts clearing the bottom of the sleeves ok?

 

Ok, first of all did you check all your clearances or did you just throw it together? If you checked the clearances you shouldnt have a problem. Did the motor turn over without the head on it?? I would have definately tried to spin it without the head on it.

Also, you should def have the timing belt on if your going to turn over the motor with the head on it. your trying to turn over teh crank with out turning the cams