Dave3891

I am looking for a little bit of information on spinning bearings on the LS motors.

The back story to this is as follows:
I picked up a 02 5.3 LM7 for a turbo RX8 project. I dis-assembled the motor and did a basic cleaning (it was in rough shape) and picked up some STD size main and rod bearings for it. I installed the bearings without any crank polishing or clearance checking (I know this was a bad idea) and put it back together.
Then installed the engine with a car intake and 42LB injectors and a H1C holset turbo (Too small for the engine)
I got the car running (HPTuners) and had some safe rich AFR for starting the base tune, did some idle setup and started/stopped the motor a few times over a few days. Everything seemed/sounded fine (Bad idea #2, no oil pressure gauge) so I took it out for a test/tune log. The car drove for about 15 minutes and seized up completely.

Now I have a pretty good idea of the mistakes I made with this motor, and when I took it back apart I found the #3/#4 rod bearings chewed up and locked on the crank.

So the next thing I did was pick up another 02 5.3. This one looked clean under the rockers and I did not want to mess with the internals so I dropped it in and fired it up (Still no oil pressure gauge....).
Now with this motor I was able to make around 10-15 test runs over a couple weeks (Maybe 40KM total) until it started ticking one day. Wasn't sure what was making the tick noise so I took it out for another run and it started getting louder and losing power as I tried to limp it home. Almost made it but this motor seized up solid as well....

I was running a pretty conservative tune and around 4-5PSI boost on both cases.


So I took a break for a few months and learned more about the LS motors. I picked up a 2010 5.3 aluminum block, cleaned it spotless, had the crank checked and polished, ordered a GT45 turbo and I am about to begin assembly.
All bearing clearances will be checked this time and I have a oil pressure gauge.

I have learned a lot with these mistakes and I realized I should have not taken the shortcuts on the motors.

So my main question is do you think that the other motors were seized from contamination and lack of oil pressure? Are there other common reasons for the bearings to spin? I would really like this new motor to last a while.


Thanks
Dave

KCS

iTrader: (20)

If the rod bearings spin, it's usually a lack of oil and there are dozens of possible causes. It sucks that it took you two engines to finally invest in an oil pressure gauge but at least now you may have some warning before another engine fails.

Dave3891

Yeah, it was more of being in to much of a rush to drive it before installing the gauge in the car.

Would something like a injector not firing and causing a lean cylinder be a possible reason for a bearing to spin? Or is it pretty much oil issues most of the time?

KCS

iTrader: (20)

Usually oil related.

the404man

Thought you may find this video of total bearing contamination interesting .. this engine ran like this for 5 years 20,000+ miles.. read below video for the complete back story on the engine.


Ok This is to demonstrate to anyone who is worried about doing their own rebuild just how tough these LS series engines are, so yeah to start out guys this is what happens to your new bearings if you do not clean your block/oil galleys out after spun bearings, sure the contamination happened on first start up do to non-cleaning of the block/oil galleys after spun main bearings and this will show just how they fared for 5 years 20,000+ miles after being contaminated..

I know this video isn't very detailed but it really wasn't meant for upload, but i decided to go ahead and upload.. because it is helpful for learning none the less

Ok back story on engine, bought the 2004 2500HD 4x4 truck used, was in a flood also was an old oil field truck.. ok.. so, she had like 74,000 miles on her.. i drove her up to about 96,000 miles, until one day while out in the boonies hunting for firewood, the oil pump bypass valve stuck open and in order for the tow truck to tow me, i had to drive about 5 miles with ZERO oil pressure back to the pavement, at the time i reached the blacktop the engine locked up..

And so since i was in need of engine in my truck asap and the engine shop here was no help.. I knew what i was about to do would be something everyone could learn from, so i decided to work with what i had and in the short time i had to get the engine back in the truck, originally i didn't think the engine would last but a few months do to the non-cleaning, and in which i was making plans to take the engine back out and replace it with another.. though it never happened, because well, the old 6.0 she was a toughie BIG TIME..

I tried everything i could to throw a rod, spin a bearing or just cause the engine to stop running, in which it never happened, i spun her to 6700rpm on a daily for the first 2 years, then, 6400rpm for a while then 6200rpm for the remaining 3 years..

Also when i first put her in, she had ZERO oil pressure for the first few start ups and since i needed the truck moving asap i said O well and held the petal to the metal lol yea still stock limiter 5800rpm on ZERO psi for at lest a min maybe longer and then bam i got prime, now with the first oil change, the oil looked like a glitter factory lol BIG TIME but after the 2nt or so oil change the oil was fine and remained fine for the 5 years and about 20,000 miles later and the video below is what we have now..

Hope this video helps others with thoughts and worries they might have and answers questions they might have been wondering about so yeah enjoy and peace

Oh also these were Aluminum Silicon bearings stockers and replacement King's

Also On the spun #4 main cap, i used emery cloth and wd-40 to sand down the high spots..

The first main cap comes off at about 3:00 min in