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I am in the process of rebuilding my '55 Chevy 235, I had it completely machined and put in all new parts. The engine is still on the stand with the fly wheel, head, and oil pan off. When I go to turn the engine over by hand I can't and I have to use a big wrench as a pry bar with a couple of bolts. What I am wondering is if this is normal since every thing is new or if I should be able to turn it over easier?

Try loosening one connecting rod at a time and see if it turns easier after each one.
Are you the one assembling the engine?

Did you lube everything up during assembly?

Everything is lubed, but I'll try taking off the connecting rod caps. I'm guessing that since I've gotten two suggestions on this, the engine should turn easier.

Just loosen one at a time and try a little to turn it over.
You should turn an engine over after each main cap or rod cap is torqued DURING assembly.
When doing it that way, you will know where a problem is AS YOU ASSEMBLE
Saves a lot of frustration in the long run.
Did you mic everything before assembly?

What did you torque the main caps to and what did you torque the rod caps to? What type of lube are you useing?

How Easily should you be able to turn the engine? My rebuilt engine, that I haven't run yet, is pretty hard to turn by hand. I can just turn it by grabbing the crank pully, and it's pretty stiff. Everything was within tolerance when assembled.

Working in a shop, I have seen more than one crankshaft rejected coming back from the grinders. Things are not always perfect. In addition, many suppliers allow you to return items that are not used. This allows the potential of bearings in the wrong boxes and damaged goods going over the counter.

I would be looking at all the clearances with plasti gauge if it hasn't been done yet.

A crankshaft with all its' caps bolted to spec torque should easily turn by hand. As each piston is installed, it will take more torque to turn the crankshaft due to the drag from the cylinder walls, especially with new rings and bored/honed cylinders. Make sure piston ring end gap is correct. I lube the cylinder walls with 10W-30 during assembly so the engine will turn over easier. I cannot turn over a freshly rebuilt V-8 just by grabbing the damper, usually requires a power bar to turn things over.

Like SoTxBoTi says,once everything is assembled,pistons,rings,etc,I can't turn an engine over just by grabbing the balancer. Even when I adjusted the mains and rods in my 67,000 mile 216 with the plugs removed, it still took a lot of force to turn it by grabbing the flywheel.
The crank by itself should turn freely by hand. Once you add the rope rear seal, pistons, cam, lifters, etc.it will take a bar on the damper to turn.The key is it should turn smoothly,which is kinda hard to explain, it's more of a feel.

I agree, turning a rebuilt engine over by grabbing the damper would be pretty difficult, if not impossible. Reasonable force with a bar is about right. We must remember here too that apparently the head is not on yet, therefore there is no valve train friction.

One thing that will drag, that wasn't mentioned, is the rear main seal.What I was taught was to set each main, before the pistons are in and without the rear seal installed. Then pull the crank, install the pistons,.....

The neoprene seal used in the 2nd series 235s wont cause a significant drag. Its the rope seal on early 235s and other engine families that can cause the rotating assy (crank rods pistons) to "feel" tight.

After burning up about 2 235 cranks, I got the "feel" for the permissible amount of drag when checking a rotating assy. On my 235 that is now running well (besides oil consumption due to guide clearance problems) I was able to spin the rotating assy by grabbing the balancer with both hands and turning. The only real resistance was when the pistons were 1/2" way up or down in their travel and ring travel per degrees of rotation was at its max. The bare installed crank would turn easily just with a few fingers on a counterweight. Its my educated opinion that the only serious friction in a 235 rotating assy is ring drag on the cylinder walls.

I used the red Clevite 77 bearing assy lube on all bearing and lobe surfaces. Its available from NAPA as a "bearing installation kit" that came with assy lube, rod bolt protectors and plastigauge.

9 times out of 10 when a 235 rotating assy wants to "bind up" its going to be a main bearing. Back off the mains one at a time and see if the assy suddenly frees up. Look at the #2 or #3 mains first. The caps are marked F and R and must be installed the correct direction.

Other bind-up causes are improper size bearing shells, or piston rings that don't have enough end-gap.

Was the crank hard to turn before you installed the piston/rod assys?

chip

Chip, that's a good description of the right drag. I have a '58 235 block with about 10k miles on a rebuild that feels like that with the head taken out and the lifters removed. Unfortunately the block has a fair amount of cholesterol in the oil passages and the cam wasn't broken in correctly so I tore it down for a clean out and rebuild.

I am amazed with all the replies I have received on this subject, I didn't expect this much help, thank you. A couple of things that were suggested I will try, one is to ask someone that knows what they are doing to come over and feel the engine for me. I am hoping that everything is fine. I guess I might of over did it when I said I need to use a big wrench to turn over the engine since I don't really have to apply that much pressure to do it, probably 10 to 15 lbs with a 18 inch wrench. Also when I turn over the engine, it turns over very smoothly and doesn't drag in any one place more than another. Thanks again for your replies and I'll definately try some of you suggestions.

I was just reading a book I just bought ("How to Build the Smallblock Chevrolet") and came across this paragraph... "...check the torque required after each rod/piston is installed. It should not increase more than about 5 lb-ft per piston/rod... it shouldn't take more than 35 to 40 lb-ft to rotate the crankshaft; if your engine uses a rope-type rear main seal, it may take as much as 45 to 55 lb-ft." Granted this if for a smallblock V8, but hopefully this can help out at least a little bit.

I'm not sure if runout on the crank had been mentioned or not,I believe its .002" max on your main journals. Hopefully you are within this tolerance. GOOD LUCK.

Well, If your calculations are accurate, 10lbs at 18 in should put you in the ball-park of 15 lb.ft.
15lb would make it 22.5 lb.ft.
IF this is correct, you are doing fine