Rebuilding an engine - what precision instruments to do measurements

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Schurkey

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Looks to me like the oil pump is one of the few parts you might save. But you'd want to verify the pressure relief valve, and maybe install a stiffer spring.
 

Schurkey

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Rod journals look pretty much all the same. Fine scoring, but not enough to catch my fingernail. Really is obvious with a bright flashlight. Rod cap bearings look almost all identical. Significant wear throughout except at the parting line. That's because the inside diameter of the bearing is slightly elliptical, right? See edit below.

Edit: The bearing wear on the last photo is considered an ideal wear pattern, according to this source, page 7: https://www.mahle-aftermarket.com/m...b-2-1114-engine-bearing-failures-brochure.pdf

...that article has really good information!
The LOCATION of the wear is ideal. The amount of wear + scoring is not.
 

stutaeng

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I decided to "practice" taking measurements on the 4.3, since that's why I started the thread to begin with. It's already apart. :)

I found these spreadsheets for taking and calculating measurements. https://www.powernationtv.com/assets/powernationtv/pdf/engine-data-sheet.pdf Practiced taking journal measurements with the analog micrometer...I had to get my TI-89 Titanium I used in college out to add up all my decimals correctly. LOL.

Then "zeroing" out the dial bore guage on the locked micrometer anvils before reading the direct clearance. After a few times I actually felt like I knew what I was doing.

Check out my clearances...the rod clearances..."there's your problem lady!" Although I think it was already obvious.
 

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stutaeng

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Well, bad news. I got ahold of the machine shop and was told that 6.0 block was thrashed and not usable. The spun bearing killed the block housing.

Darn. I was really looking forward to putting it back together and having an engine I could drop in just about any vehicle in the future. I think at this point I'm just going to abandon the idea. I'll return the pistons and maybe re-sell that crank. :-(
 

stutaeng

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On to the next project I guess...boy, I'm cleaning up the backyard.

I hope this one is a good one. There's a 2wd Allison behind it...not sure where to drop in this beast. I had bought it for my K3500, but lately I've been leaning towards finding a 2500HD roller since that's it's natural habitat with that transmission.
 

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JeremyNH

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I have a 350 block in the shop being clearanced for a 383 and got the same phone call last month for the same reason: spun bearing wrecked the block. Got a second known-good block only as a replacement and managed to salvage common parts from the wrecked one (main seal housing, lifter spider and dogbones, cam retainer). Everything else I was planning to replace anyway and at least got to tear the motor down as a first time learning experience so not a total loss. So going forward and info to others spun bearing assume wrecked block.
 

Frank Enstein

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The cross bolted main caps are perhaps why they don't want to align-hone the block. I don't see why the side bolt holes in the block couldn't be milled to make up the clearance though.
 
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