Crank tight

Hi all tried to search this before I posted .
Mega block , eagle crank that has just had the mains cut .010 . Machine shop checked clearance while they had the block and the crank. Said .0025 . Torqued the caps one at a time . #2 torqued to 100 stopped the crank from turning . All others ok , thrust sets fine .006 . Back #2 off to 50 ftlb and it turns. Planning on pulling the crank back out tomorrow night to check clearances myself. Anything I might be missing ?

Pull all the main caps and check for run out on all 5 main bearing journals on the crankshaft
if it is straight take the block with the crank in it loose back to the machine shop and show them your problem
Been there, done that more than once with bad parts

might try a diff bearing , might have a defective one ?

look for dirt / chips also ?

try some bluing to find thr tight spot ?

Thanks for the replies.
Checked run out before the crank was cut but not after , so will do . This is a freshen up after losing the thrust bearing . Only change is bearings and crank was cut .

Cap is in the correct location? Not swapped or backward? Bearing isn't stamped for undersize? I know when mine spun the bearing and broke the rod, it bent the crank .010" when measured at #3 journal.
Doug

Caps are correct. The lower shell is stamped .010 but in all honesty I didn’t check the others. Will do .

Swap the bearing from another journal and see if the problem is still there. Very well could be a bad bearing.

anymore i torque the main caps down without bearings and check the bore sizes with a dail bore gauge. sometimes the results will freak you out when you compare them against specs.

You need to check the line bore of the block. Easy to do if you have a round straight edge, just lay it in the bore and use a feeler gauge should not be able to slip a .001 under the straight edge.

I’d pull all the bearing shells out of the block except 1 and 5.

Then check for journal runout.

If the crank checked okay, then I’d remove the crank/bearings and torque up the caps and check main bore sizing with a dial
dial bore gauge.

Or you can pull everything out and do those checks in the reverse order.

I have had better luck mixing King coated bearings in my builds over any Sealed Power/Federal Mogul or Clevite bearings. Not knocking any of the brands as I use all 3. King Bearings however have given me the clearance desired that I couldn't get out of the other at times.

Thank you for all the suggestions. Will play with it tonight if I have the energy.

So just some update and looking for thoughts before I bring it elsewhere .
Took block , crank and bearings to the shop that is helping with this. This is a small shop that an old friend runs that helps me out a bit with the race car. his abilities are limited , meaning he does not have line honing or line boring equipment .

checked crank runout and it is less than .001.

checked crank journals. 2.739

put my bearings and crank in another block , torqued down and turns fine.
measured clearances with bearings torqued down in my block and all are +.002 .
all of the main bores are the same size and exactly at spec . FYI the test block that all worked in is about .001 + over spec.
Had a set of lightly used bearings and put those in my block , and its tight but turns . These bearing were about 1/2 a thou thinner than my new kings .

My next move would be to bring it to a shop that has line boring equipment .
I think what I'm having a hard time with is why ?? This was a running engine that ate the thrust bearing . Had the crank thrust repaired , and consequently the main journals cut .010 . So why would I need to get the block modified ?

Could this block have had an issue that went unnoticed until the crank was cut and this made it show itself ?
In the past this motor was hard on bearings until I started using King standard x to get a little more clearance.

Thanks for looking

I'd be narrowing it down to which bearing or bearings specifically were causing it to be tight. Then look for burrs on the caps or block.
Even a small burr will cause a problem.

Heat cycling

Any bearing or combination of bearings (the new kings) in the number 2 locks it up at full torque.
Even without any main caps except number 2 .

Hmm . It’s a 20 year old mega block . Hundreds of passes
Thanks

Bore gauge the torqued mains I bet you find out of round. A line hone will fix it up right. I had a 396 one time that the # 5 was almost .009 too wide at one position. You probably have a tight one.

Did you dial bore the individual Main bores without bearings? Either A; there are burrs in the #2 bearing bore B; the #2 bore is small or out of round. C; the #2 bore isn't in line with the other 4 bearing bores. Why? good question. Figure out if it's A, B , or C first. Your sure you are tang to tang on the bearings and the cap isn't marked wrong?
Doug

you mentioned "hard on bearings" most likely line bore is off

Without bearings.

But why would it show up now vs previously?

Just being devils advocate!!!!

Did you change from bolts to studs ??? sometimes a bolt or stud will mess things up.

And if so are the studs tight in the main caps.

Heat cycling over time can move and the old bearings wear. At same time. Then new bearings in old bore = oval

studs can definitely change cap location vs factory type bolts. do check the bore sizes. it's a real "educational opportunity"; .

Because your main clearance wasn't at .002 with the old bearing/set-up. If your clearance was 1 or 2 thou. more you wouldn't have even noticed it. I'm not suggesting you do this but I bet if scotch-brite the tight but turn-able bearings it would go away.

I think your right on here . I think this block may have had main bore alignment issues . As I mentioned it was hard on bearings until I went to a standard x then it all went away .

We did measure the bores without bearings and they were spot on spec .

Studs in 1 and 5 bolts in the rest and always has been .

Called a local shop that can line bore and they can’t take it for a month. I have one more I can try .

Thanks for all of the ideas. Just wanted to make sure I wasn’t missing something stupid .

I bet the original line bore was done with some very expensive equipment too. (just a follow up comment on another post,sorry) It must not be straight, since the bores are round.

I suspect that the fore/aft location of the newly ground thrust journal on the crankshaft is off. So the crank is moved further forward or further rearward in the block than it is supposed to be. So the bearing shell is getting into the radius on the #2 crank journal causing the binding. You could put a very thin coat of Permatex Prussian blue on the radiuses of the #2 journal, making sure to not go past the radius with it. Then assemble it, and look for witness marks from the bearing hitting the radius.

I’d be looking for a shop with a “line hone”.

I would also double check the radius on each journal. You might find #2 bearing will require some carving of the radius contact area. Something to check with an easy fix

Gus

Yeah, first thing is check radius on the bearings. And then a line hone is definitely the choice, over a line bore and then hone. Unless you changed maincaps, there should be no need for a line bore. S/F....Ken M

I thought about this as well. So I put it all together without the upper or lower thrust bearing . Same result when torquing #2 . Didn’t use the dye . Maybe I should look closer at it .

Yes, trying . Not many around and so far the two I spoke to can’t take it for a month or more .

There is a reason it is tight, it's up to you to find out exactly what it is so you can have it fixed CORRECTLY: work:
Do you have a set of good mikes, inside and outside, or a good dial bore gauge? If so on either one I would check the inside diameter of that main bore torque down and again with a main bearing torque down in it and see if you determine where exactly THAT problem is
Good luck, you can find and have it fix