6.2L Winter Refresh.

[SpareParts]

I did not post that because King Bearing is good or bad.
I posted it as it explains some difference between bi and tri metal bearings.
After reading a few articles, Bi-Metal bearings will be just fine for my application.

 

[swathdiver]

From my 2013 GMC Sierra's Shop Manual for the L9H

 

[alvocado]

Pat, I didn't see anything about why you decided to do a rebuild? You have similar mileage as me so I'm curious if you were experiencing some issues or signs of a pending failure and decided to get ahead of something more serious.

I'm looking forward to following your progress. An engine rebuild is one of the few things I have yet to tackle and I'm sure the forum members will make this a interesting group effort.

 

[SpareParts]

Want the long story or short version?

 

[SpareParts]

When i bought Cracker, i knew full well it would need engine work so no complaints.
My typical modus operandi is to buy a worn out chevy i can wrench on and sell a year later cuz im bored with it after i fixed everything.
Decided im done doing that and will keep Cracker till i die or can not drive anymore. I'm 64 so yeah.
Wrenching on my rides has become my hobby for the last 15 years or so. Been wrenching all my life though.
I do not mind at all dumping money and time into Cracker because it is fun and interesting to me.

So this engine I'm doing a refresh because of piston slap, worn pistons, high miles, trashed cam bearings and band-aid fixes. The first oil change i did on it had lots of glitter and bearing chunks in it. Every oil change i did had glitter and a small amount of chunks. Would it go another year or two? Maybe but who knows.
Right now it is not so worn i can't get away with a garage refresh, so why not?





Turns out the engine i replaced it with had many of the same problems. Some glitter but no chunks though. I did however replace the cam bearings that were severely worn. I cut open the oil filter and found the media was collapsed and hard as a rock. The filter was obviously filtering nothing and been that way for a long time.





In the spring, i will swap the refreshed engine into Cracker. The then extra 6.2 will go to the machine shop for a proper rebuild. I then plan on putting that into the wife's 2013, 5.3 Avalanche.
Sounds like a lot but not really.

I would suggest anyone and everyone should change oil and filter @5k or less.

 

[j91z28d1]

do you remember what brand of oil filter it was that collapsed inside?

after taking it apart, did you find where those big chunks came from?

 

[SpareParts]

Replacement engine: I can not swear to it but it was green and white and i think Quaker State. Can't remember for sure.

Old engine: Had to all come from cam bearings. Rods and mains look good.
#1 was flaking off around the edges.
#2 the top layer was coming off and chunks were coming off from around the edge.
#3 had a little flaking off around the edge.
#4,5 worn out but solid.

 

[j91z28d1]

huh. sure looks like a lot of aluminum in the pan pic.

I would have guessed like timing chain eating up the front cover or something.

 

[West 1]

To address your bearing question. Tri Metal bearings, copper lead tin are being phased out due to EPA standards, Copper Lead and Tin are all on the EPA list of materials they do not want humans exposed to. Like it or not that is fact.

In Tri Metal at least from Federal Mogul or Clevite the tri metal bearings were 77% copper. ( where the name Clevite 77 came from). These were good automotive standard bearings for years the standard.

For Performance engines and Diesel applications the Tri Metal Formula was 84% copper and they used a harder steel back on the bearings to reduce flexing on these 2 applications.

Both of these were tin plated to help avoid contamination and to help avoid damage on start ups. Tin plate was very thin, measured in Millionths of an inch. Later race bearings no longer came tin plated and were ugly to look at but they were very good for race engines.

Aluminum bearings were first introduced in the 70’s. They are known for very long life but were not as forgiving in failure situations, overheat or exposure to dirty oil for long periods.

Due to the EPA mandates to reduce Copper Lead and Tin Federal Mogul pushed the science of aluminum bearings. Around 2003 or so they introduced high silicon aluminum bearings that were bored to size so they had near zero size deviation. Great technology but only handled about 450 Horsepower before they broke down. These were the A500 bearings. Aluminum bearings are still built with a Steel back, the steel is the structure of the bearing while the aluminum is the part touching your crankshaft.

Side note: These A500 bearings being high in silicon and bored to size held oil in the bore grooves so these bearings eliminated start up wear and lasted in perfect condition well past 200,000 miles. Second advantage of the bored high silicon bearings was they had the ability to polish your crankshaft and any dirt in the oil could flow out the bearing grooves as the engine ran so the crankshafts came out with high miles looking better than they did brand new.

This was actually a problem for production engine rebuilders because they all had marketing that advertised all of their engines would have a reground crankshaft in them. The cranks coming out of these engines when they came in for overhaul looked better than new and did not need a re grind to be used again. They had to modify their brochures due to this. There was no reason to re grind a perfect crankshaft.

A bored bearing if looked at close has grooves like your old vynl records had but smaller.

I have been out of the industry since 2019 so information I have is now stale but FM did introduce newer high silicon bored bearings after 2004 that continued to be stronger and able to hold more horsepower. I know they had an A600 material and were working on stronger formulas that could work full time in the modern Diesel engines that run at far higher stress levels.

If I had my choice of new bearings to use I would certainly run the High Silicon bored bearings since I have seen first hand how well they work.

You can’t get Bored bearings for an old 283 Chevy or 300 Ford 6 cyl, they only offer them on newer passenger car and truck engines, they did make them for the popular GM 350 and the Ford 302 which had high volume to support the new introduction and tooling needed.

Race bearings are made stronger for sure but they also are clearanced differently than passenger car bearings. Race bearings have more clearance at the cap ends to allow for connecting rod stretch at high RPM that can pinch off oil flow. Stock bearings oil better at all lower RPM operations and are best in anything other than a Race engine that will operate at high RPM for extended periods.

Lastly, Main Bearing Grooves. The oil groove can be 1/2 groove, only on the main upper bearing, full groove that goes around the 360* bearing surface or the newest option was a 3/4 groove.

The full groove bearings are weaker because you now have a groove under the heaviest loaded part of the bearing reducing load area and increasing wear.

A 3/4 groove has been proven to offer the best oiling of the 3 options by getting more oil flow to the load area of the main bearing while still offering full support under the heavy load part of the bearing.

As far as sizing Clevite made their bearings slightly larger than FM bearings. If your clearance is a little loose with FM bearings switching to Clevite could help tighten things by a maybe 2/10,000 of an inch, not much but sometimes you want an exact clearance so you mix and match bearings to get there.

As far as the note above that bearing clearances vary now, I can’t say since I have been out of the industry a few years now. Bored bearings have zero variance, standard cast bearings do vary but size was checked at FM with electronic tools as they were made, if they were out of range they were scrapped but maybe things have changed and it has always been the engine builders responsibility to measure all parts before install.

Hope this helps. Takes too much time to write all this but it is true as I knew it up to 2019.

 

[j91z28d1]

the easy answer I came up with when I was searching is oem bearings are soft and can actually trap and keep some debris and help keep it off the crank, where a harder bearing could scratch the bearing and crank and it's forced by. all theory of course as you'd hope the engine oil was clean.

basically at stock to stock ish hp/tq and rpm the softer stock bearings are fine and might even be better than a hard race bearing. but as power and or rpm go up, you need the harder bearing.

I went with the oem replacement clevite 77 rod and main sets from rock auto of all places haha.

 

[SpareParts]

Got the block cleaned up enough to work on it now.
Now need to take out that front oil galley plug, hone it, then clean it again so i can make sure it is as spotless as i can get it.
Think im going to get the short block done first. Next month or two ill get the head work done. Split the cost over a couple month's.
Nothing special, just a few random pics.

 

[Charlie207]

Got the block cleaned up enough to work on it now.
Now need to take out that front oil galley plug, hone it, then clean it again so i can make sure it is as spotless as i can get it.
Think im going to get the short block done first. Next month or two ill get the head work done. Split the cost over a couple month's.
Nothing special, just a few random pics.

Do you have plans to plug the AFM towers? I just used the hammer-in plugs, and skipped over the more expensive versions that threaded in.

 

[SpareParts]

The bearings work very well so ill be using them again. Im just waiting for the final clean before I plug them off.

 

[PatDTN]

Small item but don't forget a new oil pressure sender and the screen under it. It's a wooly bear to do in the car.

 

[SpareParts]

There is not a screen on 2007 6.2. The sender is newer. I think 07-09 do not have a screen.
I can do the sender in the car in about 1/2 hour removing the fuel line and brake vacuum hose. PITA but not horrible.

 

[SpareParts]

Well dang, 1 cylinder has some worrisome scratches. The rest all look great.

 

[SpareParts]

Talked to 3 machine shops and the cheapest i can get it bored 0.010 over and honed is $900 bucks and i supply the pistons.
They all will clean the block, deck it then torque plate hone it or they will not touch it.

So tempting to just say fk it and just pretend i don't see the scratches. There are 2 scratches i can catch with my finger nail the rest i can barely feel.
Younger days i would just slap it back together and not give it another thought.

 

[strutaeng]

Did you already buy standard pistons? You should make sure 10 thou over pistons is something you can order and get in a reasonable amount of time. 20 and 30 thou over seems to be a more common size, it seems me? Maybe I'm thinking on the 6.0?

I remember reading a thread on tbe LS1TECH.COM soneone built an engine and soonthereafter he pulled the pan and saw a few little vertical scratches and they told not to worry about it...

 

[SpareParts]

No. I have not ordered pistons yet. Still looking at part options.

 

[donjetman]

Is that after ball honing it?