I need help figuring out how to roll in this main bearing

[FreeTruck]

I decided to replace all the mains in my '84 GMC's engine after looking at the rear thrust bearing and seeing a lone groove in the middle of the bearing. I initially just wanted to reseal the pan, but I had a moment of clarity and thought "why not replace the oil pump too, since I'm in there?". I removed that rear main cap, saw the bearing and figured it was best to replace it. I plan on doing the whole set because just doing the one seems half-assed.

So I started with the rear bearing. The cap bearing was easy enough to get out. Before I started on removing the block bearing, I cleaned the cap bearing and the crank journal, applied some Plasti-gage, torqued the cap and measured the clearance at maybe .0021". Good clearance, but that groove wasn't going to do.

For the one mounted to the block, I put a cotter pin in the oil feed hole, making sure to catch the bearing and not touch the block, and gave her a spin around and out the bearing came. Keep in mind the bearing's raised tab that would prevent one from removing and installing the new bearing at the same time, i.e. the bearing has to rotate one way to remove, the other to install.

When it came time to install the new one, I tested the fit and noticed the gap for the thrust bearing collar had shrunk. I figured the crank had slid back a little after I removed it. No problem, I just used a prybar and nudged it back forward a little. Problem is, any bit of rotation and it wants to move back. Plus, the clearance for the thrust bearing to the block is VERY tight. So it almost seems like I'll need to have one hand to rotate the engine, one to hold the pry bar when rotating, and another to hold the new bearing and cotter in place through the oiling hole.

If watched videos of this online, but none of them specifically show a thrust bearing being done and how to address these tight clearances and how to keep the crank from moving. Has anyone done this before and maybe has some tips? Thanks in advance.

 

[FreeTruck]

So per usual, after I struggled for a couple hours trying to do this, gave up and asked the internet, I went out there to try again. I figured I'd just install the rear main seal and then give it another go. And wouldn't you know it, I managed to get it started maybe 1/4 of the way with just my fingers. I was dumbfounded. I'm not sure how I did it. Once I scooted up underneath the truck again, I installed the seal and grabbed my bearing, lubed it up, and snuck it in. I have no idea how, as I wasn't even massaging the crank back and forth.

The only thing I did different was inspect the bearing before I laid back down to make sure there wasn't any burrs or anything holding up progress. Turns out I dropped the bearing and it did bounce off my cardboard and hit the ground, but I didn't think much of it. When I looked at it, there were a couple of miniscule indentations from whatever it hit on the ground. Keep in mind my truck isn't 8 feet in the air; the tires are barely up off the ground. I took a flat file and ever so gently ran across those high spots and smoothed them out. After that I went to install it, and it slid right in. I couldn't believe it.

I rotated the crank a little more to brink the oil passage of the crank back around, inserted my cotter pin, and gave the engine about another quarter spin. The bearing pushed right in nice and flush on both sides. Win for today.

The lesson here is bearings are WAY softer than you think. BE CAREFUL and do not drop them. Check them three times for dirt and debris before you click them into place. It makes me think, just what grade of Play-Do does BMW use for their bearings if SBC mains are this soft?