put our brand new yblock on the test stand, new rings, bearings, etc. when we got it all together last year it was very hard to turn over by hand, I cant get it to turn over at all now by hand, dont want to risk busting off the balancer bolt or stripping it out...do we dare put the starter on and see if it will crank it over? how tight should this be?? dont want to risk screwing something up now that its this close...we rotated it each time we installed a piston/rod so I dont think anything is wrong there?? help? thanks-
hopefully it was stored in a dry area without temp fluctuations...or condensation could get inside and rust things.
Your remark about "it was very hard to turn over by hand" is troublesome. It sounds like the bearings "might" not have enough clearance. We need more information to make a guess,like : was the crankshaft reground? Were micrometers used to determine what size bearings you put in it? After ***embly,and torquing the connecting rods,you should be able to slide the rods on their crankshaft throw,a slight amount (~1/32") toward the front and back of the engine.If they won't move with finger pressure, something is TOO tight. Did the crank turn freely before you started putting pistons in? If you have a big fat wallet,go ahead and try to start it before you find out if it's too tight. You can pull the pan off and try putting some Plasti-guage strips in between the bearings and the crank to see if you have enough bearing clearance.Get it at NAPA. It sounds like somethings not right. Ya' better be sure before cranking it up.
Should not have been that difficult to turn. It's not what you wanna hear, but, stop where your at, and fix the problem now. It will cost you some time but save you some money.
What kind of lube did you use when you re***embled the engine?,if done right,used right parts it should have turned over easy.Definitly don"t put a starter on it to turn it over,you can mess it up more.Is it just a stock rebuild or what?Really sounds like either,wrong bearings or just not ***embled and torqued right and lack of lube.
used white ***embly lube and engine oil when putting it together... stock rebuild w/ exception of a slightly larger cam... stored inside in climate controlled shop... think we will pull the pan and plastigauge the main bearings...thought everything down there was standard but hard to remember now...have had a number of students working on this over the course of about a year, hard to remember all the details...
would we damage anything if we loosen all the main caps slightly and see if it'll turn by hand then? wouldn't that isolate the problem to the main bearings or main journals on the crank??
I'd loosen the torque on the rods first. Back off just till the nut moves free. If it is still tight, do the same with the mains.
Did you prelube the motor? I would do that first befor trying to turn it over.The plastigauge next rods and mains.Pull the plugs and oil the cylinders.
The students will likely be the source of the problem. They can be good...or bad. As the others have said, someting is not right, if clearances were machined properly then the trouble may be in ***embly or maybe even cam bearings ? Definitely do a full teardown and careful re***embly if thats what it takes to have it turn feely.
You want to check the rods to ***ure that they are properly installed with the bearing offset away from the journal radius. I am ***uming this is a V8. Caps on the right way. Flywheel bolts not to long and dragging on the block. Mains right way around. Stuff like that.
"...thought everything down there was standard but hard to remember now...have had a number of students working on this over the course of about a year, hard to remember all the details... " always keep a journal, notebook or diary on everything you do to your engine or car... (Yes I have trouble following my own advise....) <!-- / message -->
yep it was pre-lubed... this is a y-block v8... we are tearing into it now, let you know what we find...
A fellow brought 1 like that to me, sat over 2 years, didn't have the bread for a tear down so we squirted some Marvel Mystery oil in the cyls. left it sit for 2 days and just bumped it with a breaker on the crank and it loosened up. Didn't hear from him again so I ***ume everything was peachy.
If it was hard to turn over when you were putting it together something is wrong. It is either wrong size bearings or a bent crank. You should be able to spin the crank in the block when you install it, I always check the rotating resistance with a inch pound torque wrench before I start installing pistons and rods.
It should take between 45-50 ft-lbs of torque to turn a completed ***embly. Did you use a rope rear main seal ?? >>>>.
Ok the ultimate stupid question here. Its a short block or a long block? By hand do you mean with a wrench or grabbing the balancer by hand and trying to turn it over? Would compression have anything to do with it? Just curious I guess.
"Students working on it", Thats the problem.I know they need to learn,but somebody cranked up the torque wrench. More supervision needed.
in shop cl*** in the 60s we rebuilt some small engines, some ***hole put a socket in the clyinder to be cool, he never was after that
You may want to check that the rod caps are all on the rod that they are matched to and none are turned 180 degrees from the way they should be. Same with the main caps. I think we are all ***uming that you know that rod caps and main caps can not be switched around to other than their original positions ...right?
Ditch the rope seal and get a good rubber rear main seal kit, they are available on e-bay or elsewhere. (And install it properly )
definitely tear it apart...i would start and work 'backwards' from the ***embly...take out the plugs and try a spin....then...undo the rockers ***y/take them off and try again - maybe too much force on the cam...next remove the pan and loosen the rod bolts - try the spin again....then loosen the mains and try again....if you did not plasti gauge, could be the problem...if you did not line bore the block and did not check the crank for trueness, you may have found the problem...good luck
Your comment is offensive if you would go back and read the threads Dan has posted over the years. He is NOTHING BUT a hands on teacher and I am proud to call him a friend! We need more educators like him. He is one who actually gives a **** about kids in an era when shop cl***es are as rare as Chicken Lips.
Had the same thing happen in a shop cl*** years ago, swapped main caps. Engine was previously rebuilt and the caps were stamped wrong by the PO.
it has to be clearance concern . all the motors i have done , i can spin an ***embles short block with a pair of channelock pliers on the crank bolt (i know ! wrong tool !) just enough tension , its the feel . chamfer on the rod caps-wrong dirrection ? clearance on rods and mains ? rings ? file fit ? etc ....etcc.... just sayin .
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