Yea I think your right . As bad as it sucks ... I'll keep ya posted on what I find even though I have a good idea.

 

LesMeyer got a decent deal shipped from Jegs just FYI.

 

Ok thanks I'll check it out

 

Doesn't sound like you bored the block, replaced pistons, or resized rods, so I assume the block wasn't hot tanked by a machinist and the engine was cleaned at home after a diddly ball hone job? This can be a big mistake in an engine, especially one that had previous bearing problems. But since you say the cam bearings were replaced (not many people do this at home), the machinist could have checked all this stuff out and cleaned the engine well - I just don't have this info. Also not checking main bore alignment would be a mistake, as would not replacing the radiator (oil cooler) or cleaning remote oil filter adapter where old bearing material can hide.

I had pretty much the same thing you are describing happen to my carefully and completely rebuilt engine after 1500 miles. Bearings went out again, but seemed perfectly fine before that time. For my engine, I'm convinced it was due to my own blonde moment where I got grit in the engine during oil pump priming. You can read through my huge project thread about it if you are interested. It definitely wasn't my first rodeo with rebuilding an engine, but it was most certainly my worst experience. Mahle engineers confirmed that my bearing failure after rebuild was due to "debris in the oil"

https://blazerforum.com/forum/2nd-ge...g-valve-87514/

Mahle makes a booklet on diagnosing the cause of bearing failures. I picked mine up at a large street rod show. Here it is as a PDF.

http://www.mahle-aftermarket.com/med...s-brochure.pdf

Sounds like you had a bearing fail during Crank Sensor Relearn. Although it requires 4000+ RPM to do the relearn, it really isn't the fault of the person doing the relearn. Some inexperienced people have to try the relearn again and again until they finally get it to take (I know I initially did). Still a bearing should go 4000 RPM without failing, but one on the way out won't take it many times - see what I mean. Once you know how to meet all the requirements for the relearn and the exact order to do things as far as key off/on and clearing old codes, you can get it to take first time. Maybe I do extra stuff, but it works good for me when doing it with HPTuners Software.

Warm engine to normal operating temp.
Turn key off for 10 seconds and then back on
Set emergency brake enough to turn on the brake light.
Connect scan tool and clear codes.
Hold foot brake down and do not release
Start engine and let idle for 15 seconds or so
Immediately initiate relearn procedure on the scan tool and rev engine quickly to fuel cutoff and release throttle
If does not hit fuel cutoff as soon as you get past 4000, turn key off for 10 seconds and start again.
Be sure to clear codes again each time you try the relearn. The relearn procedure will not trigger with a current misfire code set or if the check engine light is on.

I ended up sticking a GM rebuilt in mine just because I was so tired of working on the vehicle and wanted to be done as soon as possible (and have a warranty). The GM rebuilt cost less that the machine work and parts on my original rebuild (I went through absolutely everything in my first rebuild), and repairing the original was apparently going to cost a lot again. GM crate engine has been great so far - I have about 6000 miles on it now.

Nice thing about Jegs is free ship/no tax/no core and you get to keep a great shipping container. You will want to use the LU3 to replace your L35 as the knock sensor mounting on the block changed in 2001 and GM doesn't offer the 2001 L35 as a rebuilt. The GM warranty is 3 years/100,000 miles and does require the radiator (oil cooler) to be replaced!!

GM Goodwrench 4.3L 262ci V6 Engine | Chevrolet Performance

Any questions please ask.

Les

 

Ok so I tore it back down and thought I would post a few pics to give you guys an idea of what I found. Let me know your thoughts.

 

it looks like time for a full rebuilb some times some people try to cut costs and dont bore or rige ream that ware on top of the bore will cause you to lose the botem end so botem line anthing worth doing is worth doing right

 

Bearing is definitely bad. See post#14. That is a rod bearing, correct? FYI any bearing that has been rattled before is going to need it's rod or main bore resized. You still haven't described what was done and checked on this engine before. Sorry to hear about your troubles. I feel for ya! Been there!

 

Engine had a bad rod bearing when it was rebuilt. Engine wasn't hot tanked but was cleaned used pressure washer and air. pistons and rods are all the same none was replaced. And a new crank installed. Connecting rods was cleared ok by machinist. The picture shows a rod bearing. Interesting thing is all the rod bearings will now just fall out of the caps and rods. Looking at them they are egg shaped. Now I could understand one bearing doing this but all of them. Bearings was plasti gauged for proper clearance. now I will be taking the rods to someone else for second opinion . Main bearings looked ok

 

This is a photo of a rod bearing on the crank...see how it has to be forced on the crank.

 

Usually the bearings fall out of the caps/rods only on cylinders where the bearings have been rattled. The excess clearance allows the bearings to be sprung from the pressure of the cylinder firing. Are you sure it is all 6? Do they all look bad? What about the mains? Are they retained in the main caps? if it was debris in the oil the mains would also have some damage (scratches). You may be able to tell more from them than you can from a completely destroyed bearing.