I'm rebuilding a pair of 1962 Chevy 283's and after having the blocks cleaned,magged and bored and honed, I ordered a set of main and rod bearings in standard size. Using a standard crank, I proceed to torque down main bearings in sequence. After only hand tightening the bolts, with assembly lube on the bearings, she wont spin freely anymore. Question: If the supplier sold me large journal bearings,versus small journal bearings,could this be the case? I'm only on the mains right now,haven't installed the rod or piston assemblies yet. I know if I torque to 65ft lbs.,she'll be tight as hell.I have forged steel cranks in both engines. Thanks in advance for your help...
i don't think large journal bearings will go into the block/main caps. measure the crankshaft accurately with a micrometer. and check the back of the bearing shells , should say STD. if they are undersized you should see something like .010 , .020 etc
Make sure the main caps are not mixed on the block and, since you have 2 blocks, mixed between the two. Should the caps be mixed they can be sorted with a dial bore gauge (preferably with a .0001 reading gauge).
You dont know any such thing yet. Often everything is only straight when torqued. Pontiac engines in particular often act like that. Try it and see. And what was said just above me is valuable too. Don
rjaustin421 & Dolmetsch have really pointed you in the right direction. And be sure you have all the caps in thier original locations and pointed in the correct direction.
If in doubt just put in first and last caps, torque and check ,if it's free add caps one at a time to locate snug one.
Or take the crank and bearings out, put the caps on, torque the bolts, and see if the parting lines on the caps feel "right" (not misaligned) This should tell you quickly if they are the right caps for the block. The wrong bearings are .1" different diameter, they won't fit into the block or caps without mangling them
Go full torque. If you don't go full torque your bearings don't have the crush they need, and many times the crank will be tight.
Joe Cool- Yours was the one I went with and everything went fine. I was real tired the first time I did this, and knew enough to stop because it didnt "feel" right. Thank you, I had them mixed matched. Mikey
Nice to see that you stopped, took notice and fixed the problem. It always amazes me how many guys will just continue on, complete the engine and wonder why it all goes to crap in the first couple minutes of running. You did well today!
ain't this the truth!!!? I teach a basic engine blueprinting class, the second to last class before graduating from an auto technician program---and it NEVER ceases to disgust me how many students can't diagnose their way out of a wet paper bag!
What do the other teachers say when you mention this to them? Seems like the program needs a little tweaking.
Do the 283 blocks have a rope seal? If so, take the ropes out and try it. Sometimes the rope seals are so tight they are hard to turn. I agree with the guy about using plastigage that should remove any doubt. Good luck.
It is difficult to tell from this whether you are blaming the students or the teachers for the lack of diagnostic skills.
I think it is just people -- there are not that many that you meet that are good problem solvers, mechanically inclined, logical . . . or pray to God - all three. Years ago when I was in the Plymouth Troubleshooting contest (in Los Angeles), we trained for almost a year -- very few of the original students made it to the end and only two got to go. Fortunately for me, I was one of the two. Some guys that you initially thought were pretty smart - just fell by the way side when they had to truly diagnose a multitude of problems . . . on their own. I'm in the software business (I lead R&D) -- same thing goes with programmers (any creative type really). Some can solve very complex problems . . . some will never. The ones who are always the best are what I call 'visual' - they can see things in their head . . . the entire problem.
my apologies to the original poster-- it was not my intention to hijack the thread from its original intent, and turn it into a discussion of automotive technical school instruction. There are plenty of other threads for that. Bored and Stroked made a topic appropriate comment to the OP that he was wise to have stopped and reapproached the problem. I simply meant to concur, based on my own, VERY frequent observations of engine assembly issues. good on you Anchorboy46
I agree with MoparSled . . . I will take my "thread hijacking posts" and get the hell out of here Let us know how the motors turn out - seems you're on your way!
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