I'm assembling my 350 small block for my 86 camaro. Got new parts to rebuild it, and ran into a problem the crankshaft won't turn at all. I put all the pistons in with new piston rings. I got a socket and breaker bar and that won't even help turning the crankshaft. I tried WD-40, PB Penetrating oil, etc and nothing. I also don't have the cylinder heads on the block yet as well.

Does anyone have suggestions on why and how to fix this?

 

well, did you take the crank out? if so did you re install it straight and squarely? what bearings did you use? did you measure bearing clearances? did you put the rod and pistons in backwards? tell us what EXACTLY you did?? take it back apart cause something clearly is not right.

 

Yeah something aint right for sure. At this point you still should be able to turn it with a std 3/8" drive ratchet.

Was the crank easy to turn before you started putting rods/pistons in? It should have turned easy with your your fingers on the counter weights of crank.

You had to turn crank as you installed the diff pistons, at what point did it get hard to turn?

Sounds like you have a main bearing cap backwards or out of order... Or you have a rod/rod cap turned the wrong way

Each main caps must go back in same places they came from. Each rod cap must go on the rod it came off of, and the rods has a flat side and a chamfered side and must go the right way on crank

 

Probably have rods in backwards.

The bearing tangs MUST face downwards i.e. away from the crank. The bearings are not symmetrical; if they're backwards (tangs up/toward the cam, the wide side will be sitting on the radius at the end of the journal, and it will both bind there, and will force the 2 rods on the journal together, and bind against each other.

 

yep you either have a rod cap or main cap on backwards . Pull the rod caps make certain the bearing locks are on the same side same with the main bearings if that’s all good then you have some bearings that ain’t sized correctly make sure to clean the penetrating oil out and use assembly lube to reassemble…. You probably need to plastigauge the bearings make certain ur bearings are the correct size

 

I've been a mechanic all my life and still see so many mistakes made by people who think rebuilding an engine is easy. There are so many little things you are never aware of while building an engine. Anyone can slap a bunch of parts together and say they assembled an engine however when someone "builds" and engine, that engine is assembled and disassembled multiple times during the course of a build to check and adjust tolerances as required.

As already mentioned, the most probable cause would be a bearing cap/rod is backwards however there can be multiple other reasons, the crank can't be rotated.

With the crank in the block and no rods/pistons installed, could the crankshaft be rotated at that time?

Pistons all facing the correct way? Rings gapped to recommended spec? Rod and main bearings the correct sizes for the crank?

 

Glad you registered just so you could reply to a thread that was just shy of 9 YEARS OLD. I applaud your use of the Search function. Assuming of course that it wasn't just The Google that brought you here.

You're right; you posted pretty much EXACTLY the same thing I did (not that just because I said it, that makes it "right"; butt, YKWIM...); butt after all this time, either he got his motor put back together right, or it blew up and he found a new hobby.