I just rebuilt some heads on a friends 305 SBC. I put the heads on and rotated the crank by hand to adjust the valves. At this point the motor was turning over freely by hand (with a ratchet on the crank bolt). The motor sat for 2 weeks and then we got around to putting the intake and exhaust manifolds on. Now the crank will not budge. I loosened up the valves and still the motor will not turn over by hand. What am I doing wrong?? The spark plugs are not in yet. Thanks in advance.

Did some coolant run into the cylinders ?
Maybe be a little rust built up on the cylinder walls.

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Dean Call
Overland Park KS
Gold member #3
A.C.E.S. # 00235
N.C.O.A. # 4350

macc.chevelles.net (http://macc.chevelles.net)

Man, very strange. As near as I can tell you did everything right, nothing wrong. I will ask some dumb questions next. When you put the heads back on, did you use sealer on the head bolts? Plugs not in rules out the cylinder being full of water. The only thing that makes any sense is the rust deal that Dean brought up. Got me.

I had a deal happen once before, one of the intake bolts pinned one of the push rods, can't remember which motor it was on.

Wally
Gold #67
67 malibu

Old age is a terrible thing!!

Did you try actually cranking the motor with the starter?

Mike
Gold #34

Might take a look at the intake manifold bolts. If you get bolts too long in a couple of the holes they will hit the pushrods. Might bind up the engine, from experience I can say it will sure ruin some push rods real quick. tom

Are the spark plugs installed? were they before?

Installing the spark plugs will make it much harder to turn.

DO NOT !! Just hit the starter!!!! If you can't turn that motor, with the plugs in, with about a 1/2" breaker bar and no grunt, something is wrong. If the rings are rusted then you need to have a heart to heart with the builder as they should be a oily mess till the engine is fired. I can't think of what it might be except maybe a bolt was used to hold up the fuel pump rod and not replaced with a short one Maybe. Are there any small children running around the shop? I know how they like to help daddy fix the car and may have dropped something down in the block. Gotta love e'm.
Harley

I would guess that the cylinder walls have a find coat of rust which is binding the rings. My brother in law had a problem like this last summer (Humidity) with an engine he rebuilt last summer.