pls help: rod caps too loose?

hi anyone,
this is a troublesome problem. i got a 92 Chevy Corsica V6. i took off two of the rod caps to inspect the bearings. they have a perfectly normal pattern of wear. no problem.
oil and replace the bearings and caps, slip the rod caps over the rod studs and start to tighten the cap nuts. i tighter the nuts to 20 #s and the crank won't turn. its hopelessly wedged. the Haynes manual says 39 #s.
everything is right and in good shape. scratch my head. loosen the cap nuts and it cranks normally by hand with a wrench. tighten the cap nuts at half the rated torque and the crank is frozen solid. didn't touch any of the other rods.
so what the hell? no i didn't do the plastigage. but why should i? the wear pattern is perfect. and it was turning just fine before i started. i used the torque wrench on some of the other nuts and it seemed that they weren't torque as much as they should be, but then how much torque do they need?
thanks anyone, Louie
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
OK i'm still working on this. i verified that the caps were not switched or reversed and the bearings are properly oriented. still hopelessly frozen with only one of the caps tighened down at half the rated torque.
any help would really be appreciated.
louie
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
"Louie"wrote

How do you know that they weren't switched? Did you mark them? You know that the two bearing tangs (upper and lower) go together? Did you happen to drop either one of the caps? Be honest, because I have done this and it "will" distort the cap enough so that when you torque it up, the engine will not turn over. I know this from experience.
Ian
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Check bearing part number on old bearing. Check part number on replacement, if different brand, there could be foul up. Plastiguage would tell you oil clearance, which you know is zero. Did you use locktite on back of bearing ? If so, when locktite dries, it expands, reducing clearance. Are the bearings seating properly ? Push suspect pistons up, boot studs, to protect, taking those cylinders out. Try rotation again. Try bearing shells in another cylinder.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Motorsforum.com is a website by car enthusiasts for car enthusiasts. It is not affiliated with any of the car or spare part manufacturers or car dealers discussed here. All logos and trade names are the property of their respective owners.