Well, I think I've found the source of my vibration. Question now is: Where do I go from here? Some of you may remember, Motor developed a vibration after I had a converter baloon, and the flexplate bolts smacked the pan rail. Visually, I see no issues with the main webbing. Pics below are of the main bearing issue I've found. All the bearings look bad to me for a 3 year old, 5000 mile motor, probobly a result of the vibration that looks to be related to the #2 main, which is obviously fried, and it would appear that I shut 'er down just in time!

Weird thing is the bearing no longer fits in the saddle correctly. Both at the saddle and cap, the bearing will rock back & forth. When I pulled caps and the crank, all bearings stayed in place except #2. Cap half stayed with the crank when I lifted the cap, and saddle side did the same when I lifted the crank.

The mainline of this block was honed, and the crank was turned down from RB dia. to std. B dimensions (413 crank). bearings are cleavite P series. Motor always showed about 40 lbs of oil pressure at warm idle, and 60 while running from day one, and never changed a bit up until I tore it down.

My plan is to have the crank magged and checked out completely and see where that takes me.

Thoughts from you guys?????

Caps with bearings.

5 4 3 2 1

close-up of saddle bearing. You can see the gap between the bearing and saddle on the non-tang side. bearing dia. does not match saddle dia.

If you ask me and I don't know why. But you got a lack of oil to the mains all of them . what all has been done to the oil sys like oil holes-block off- top end oiling- . ? you might of had good oil pressure but not where needed.

The rod bearing shown in pic #3 doesn't look too good either.......clearly a problem somewhere.
It looks like the oil was carrying around a fair amount of debris / crud too.
Check the crank for straightness while you are having it magged.
I'd pay some attention to the block too. Mag the saddles and eye ball everything closely.

You, not your machinest, should check the crank for straightness in a set of V blocks. My second thought is debris in the oil passages before engine start up, is the camshaft okay on all lobes Measure the actual lobe lift on all lobes, easier to do in a lathe The very first motor I put together after a minor overhaul did the same thing as yours looks, my camshaft went flat do to me being yuong and dumb, used lifters on a used cam BTW, I've done worst since then like breaking a rod in the lights on my original numbers matching block in my 1963 M.W. 415 HP stocker

Measure your thrust bearing to see how much wear was done when the convertor thrust-ed forward. All that crap was floating around your oiling system probably taking out the bearings.

Looking at the #2 bearing in both the block and cap - I wonder if the bearing was mfg incorrectly. It would not appear to me to have enough crush to be retained correctly in the saddle/cap. Does another of your bearing - say #1 - have the same fit problem if placed in the #2 saddle?? If it also has the same fit problem - and - this block was honed - maybe that saddle was machined incorrectly. Also that much gap would cause a loss of oil pressure at the parting line.

No oiling mods have been done with this motor. Perhaps when I rebuild, I should limit oil to top end (???)

I bought the block from a private party already cleaned and bored, then I bought pistons to match the .040 overbore. It had new plugs in all the galley's already, so I didn't re-check the passages. looking back, I probably should have had the machinist re-clean it. I had my machinist hone it, deck it, and align hone the mains, along with doing the crank.

Visually, the cam looks okay from what I can see through the bottom. But, I haven't torn the top end apart yet.

EDIT:
The other bearings fit into the #2 saddle correctly. Its the bearing, not the saddle. I assembled the motor, and although I'm not a seasoned engine builder, I paid diligent attention to the details, and I'm positive all bearings fit well and consistent at assembly.

I would hope that the machinist cleaned the block after the decking, line boring and final honeing.

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looking back, I probably should have had the machinist re-clean it. I had my machinist hone it, deck it, and align hone the mains, along with doing the crank.

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Wait a minute, do I understand this? Are you saying that there was no block cleaning after your machinist did the honing and decked the block?

There is a lot of junk in that motor.

Sorry to say this guys but the person doing the final assembly is responsible for the final block cleaning.

Perhaps I miscommunicated what I meant. What I mean is that I don't believe he cleaned out the galleys. The block was clean when I picked it up, and I believe he cleaned it up after the machine work, but I don't believe he removed the galley plugs and brushed out the oil galleys. The plugs appeared to have new silicone around them when I bought the block, and it appeared that they were cleaned when the block was bored. I could be wrong about that, as I did not confirm the galleys to be clean. He very well could have done it as standard practice, but since he did not bore or assemble, I assumed he did only what I asked for. My bad, as I agree that I'm ultimately responsible.

I'll definately clean it out good, now!

Always, always, always..and I cannot stress this enough, always, remove plugs and clean out all oil passages before final assembly. It does not take much debris to cause a big mess. Get a good set of brushes and rod and flush out each passage. I like to do this twice per passage. Then use compressed air to dry. A white paper towel should stay white on all surfaces when you are done.

Live & Learn, I guess.....
Good news is that perhaps all I lost was a set of bearings and gaskets. Heck, almost sounds like a good trade for some worthwhile knowledge. And if the cause of this issue is in fact assembly "grit", I would consider that much better than what I feared.

I'm still leary of the crank, though. I'll have it magged and checked out and report back on what I find.

I've seen guys forget to polish the crank and just as important the oil holes will need to be de burred chews a lot of debris out in a hurry and bearings go bad form there.

then
I've seen guys nick the crank on the main studs as they drop it in? buddy did it once and the bearings started looked to like that after a short break in he found the debris in his oil filter check then pulled the pan had to pull his motor back out.

Around the same time A guy that works in my garage behind the house did the same thing! I found it after turning motor over a bit by hand and found my aluminum rods although clearing had next to 0 clearance when I pulled the rods low and behold the nicks where pulling debris off the bearings already and causing quite a mess and i had just been turning it by hand.
Anyways little file to take nicks off re polish crank new bearings and all was fine glad I found it before i ran it!
Next time I put plastic covers over main studs (crank girdle they are real long!)


Anyway I would have kicked his butt but hard to kick your own butt!

I'll bet it was one of the above and or the block prep.

Check and re polish the crank clean the block new bearings and I'll bet your just fine!

That #2 main bearing lost it's form due to overheating probably from lack of oil judging from the photos.

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A guy that works in my garage behind the house did the same thing!

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Love it, that guy screws my stuff up sometimes also lol

There's certainly a lot of trash in the bearings, but I think some of you are really overlooking the obvious cause of failure. Take a good close look at the wear pattern on those mains and think about it.