Rebuilding a 94 one piece rear main seal chevy 350. I now have the heads on (plugs out) and its taking a great deal of force to turn over. Ive installed new main, rod and cam bearings and piston rings and all covered with assembly lube. With just the crank and cam in, no chain, i could turn both with the push of a finger. All my main and rod bearing clearances measured in at .002, perfect for rod and .0005 tighter than spec for mains but still good enough to run 5W30. Installed my pistons (rings gapped between .018-.020 and got noticeably tighter after each one which i know is normal and had coated the pistons and walls with 5W30, not assembly lube. Still was able to turn it and i know resistance is normal since the rings are new. Then double checked piston and cap orientation and everything is correct. Finally installed the heads, oil pan and rear main


and go to set the valve lash and i feel like im going to break a bolt off the stand trying to turn it with a pry bar, any ideas?

 

A new sbc with plugs out will take a 1/2" breaker bar on the crank bolt to turn it over. If you bolt on a flexplate you should be able to grab it with both hands and turn it over.

 

Don't use the crank bolt to turn the motor with, lest your next post be "how do I get a broken off bolt out of my crank and repair the crank afterwards?". Use a crank turning tool; something along the lines of https://www.summitracing.com/parts/sum-g1062 or https://www.summitracing.com/parts/pro-66782.

Using motor oil as build lube isn't a problem, let alone The Problem. Although, I prefer to use 2-stroke oil, since it's designed to be in cylinders in the first place, and doesn't foul plugs and all that like regular motor oil will.

A newly built motor will usually take around 35-40 ft-lbs to turn over. Putting heads on the short block shouldn't matter in the slightest as long as there are no spark plugs in them. If it takes more than 50 or so, something isn't right. Once the valve train is installed and adjusted it'll go up somewhat.

 

In "How to Rebuild SBC's" by David Vizard, he claimed 55 lb-ft to turn a freshly put together SBC.

 

And that's why you need a 1/2" bar.........your going to really stress out a 3/8 trying to turn 55 ft#. Which, by the way, is less than the 60 ft# that the bolt torques to........which won't snap it off. I didn't think I had to mention that to somebody taking on the rebuilding job. I guess I assumed common sense would tell you not to turn beyond the bolts torque spec

 

What your experiencing is ring drag. Which can be significant. New rings are very "square" to the newly honed cylinder walls. That is where all the extra effort is coming from. The longer it sits without a start up will get a little tighter as the oil used to lube the pistons drips off. There is a socket that goes on the crankshaft without the balancer on to turn the engine with a breaker bar. I got worried the first time I experienced that. After the initial 'run in' it got easier as the rings seated into the cylinders. And do not use the small 3/8 bolt on the crank to turn the engine. It will break. As someone stated earlier sofakingdom did.