350 chev rebuild

Hi Guys,
I am currently rebuilding a SB Chevy 350.
New rings and conrod shell bearing in, I have torqued the .40 conrod bearings to 45 pnd, they are not GRP bolts so 45pnd should be correct.

When i came to turn the engine around to torque the bolts i couldnt get at it is impossible to turn.

Do I need to make up a tool to fit on the front pulley to get leverage or should i be able to turn it by hand ?

With all bolts loose i can easly turn over by turning to flywheel by hand, when i torque both bolts on only one conrod i cant turn engine over at all.

Thanks,
Mike:?:

 

did you lub the bearings and put oil in the cylinders?

 

Yes assembly lube on bearings and pots are oiled not sure whats going on ?

 

Con rod bearings wrong size?

 

That seems silly at first glance, but it happened to me years ago. I bought a rebuild kit with a 'remanufactured' crankshaft, and they gave me the wrong size main bearings for what the crank had been turned down to. Like to drove me crazy for a day or two....

 

Bearings are .40 as they should be

 

just takes a couple of grains of dust between the conrod and the back of the bearing shell and will lock it solid !!
Have to check the roundness of the end where the shell fits in !! use a inside micrometer and do a inside measure in a few places ,they can go out of round !! so its possible to OS outside and OS inside shells stuck that a few times !!

 

you did do a quick and simple clearance check with plastigauge ?
were the rods resized?
I wouldn't change bearings without having the rods resized as when you add the new shells you will most likely have different clearances on the crank due to the rods not being round

 

You should turn the engine after you torque each main and then each rod. That will show you if one is a problem. I always do a whole turn after each.

 

Plastiguage the bearings

 

Thanks for all the advise guys, (nothing is ever simple)

 

Yep, Plastigauge the bearings, somethings not right and the usual reassembly practices weren't followed (as Gonzo noted). With the rings in place, the engine will be fairly hard to turn by hand, so yes, use a socket on the crank bolt and turn in the normal rotation direction. It could be one of a number of things. Recheck all gaps and thrust faces. You can't use enough assembly lube.

 

I've rebuilt many chevy small blocks. Did you do the diss-assembly, were all of the connecting rods and caps numbered. The first thing to check is that all the caps are on the correct connecting rods and none are turned around. If this checks out then you need to determine if the crankshaft is actually ground .040 undersize. The best way is to mike the crank. If you can't do this then you can check the clearence with plastiguage. To get an accurate check you need to have the bearings dry and tap the piston down so the top rod bearing is tight against the crank. If the plastiguage is completely flat then you probably have the wrong sized bearings then you will have to have the crank miked to determine the correct size needed. I've had reground crank kits that had the wrong size bearings. Usually the crank kit will come with plastiguage if not you can get it at most any parts suplier. Remember when rebuilding an engine keep everything absolutely clean a little grit can realy do bad things.

Dave T

 

Thanks Dave, a lot of good detail there gives me a couple of things to check

 

It wouldn't be the first time I've bought 10 over bearings, but received standards or 20's.