2008 Suburban Engine Swap - 6.0 to 6.2

[strokersace]

UPDATE:

I was able to get the L9H bought. Picked it up Friday evening. There was a death in his family that delayed getting it pulled. He had the rest of the Yukon XL there still, but a friend was supposed to be coming to buy it to swap the interior into his Tahoe. I'm going to be reaching out this week to see if he wants the rolling chassis or not. Going to try to get it bought for parts...

Either way, I didn't have a chance to tear into it this weekend, but plan to in the next couple of nights. Going to pull the heads to check the bores, pan to inspect the bottom end, etc. Then to start ordering parts!

 

[strokersace]

Well, finally had a chance to tear into the L9H engine last night to see what I was dealing with. Not pleased with what I found to be honest. Inside is filthy, with crud buildup in the bottom of the pan. Cam lobe on #7 is worn badly. Lifter roller still spun ok, but galled up pretty bad. What I really don't like is the cylinder walls of #7 and #8. Both have vertical wear grooves that I can feel with my fingernail. #5 has some as well, but not near as pronounced. Crosshatch is there in all cylinders but the front holes are definitely better than the back.

I'd appreciate some feedback on these cylinders. I'm thinking if I keep with it, it's going to need to be bored. Dang sure wasn't planning on a full rebuild. But if I'm going to stick with the 6.2, I only want to do it once.

I'm seriously considering yanking out the L76 and tearing it down to see what I have. With 190k+, I obviously run the possibility of it having issues internally as well. But if the cylinders look good on it, I might be better off fixing it.

Cam Lobe:


#8 Wall:


#7 Cylinder:


#5 Cylinder:

 

[strokersace]

Piston skirts have the same vertical wear marks. Dropping the block off at the machine shop today to get an assessment on if we can hone it out, or if it'll need bored. At minimum re-ring the pistons if a light hone cleans it up. Worst case, bore with new pistons/rings.

Still haven't landed on a cam yet. Definitely going aftermarket, stage 1ish. I do not plan to change the converter. On one hand, I think I'll benefit from keeping VVT with the 4spd trans. But with 4.10's, it pay be a non-issue... On the other hand, I like the simplicity of non-VVT 3-bolt cam.

If I don't mimic @Geotrash and do a non-VVT setup, then these are the VVT's I'm considering:
https://www.summitracing.com/parts/cca-156-401-13#overview Comp Cams 156-401-13
https://gwatneyperformance.com/product/gpi-low-lift-vvt-ls-truck-camshaft-6-2l/ Gwatney LLT1 VVT

It seems from reading on here, though, that the the ones using hptuners are having issues getting them (well the Gwatney at least) to idle correctly. I'd be using Blackbear, so maybe I'll give them a call and see if they have any suggestions.

The rig isn't going to be a strictly tow vehicle. Matter of fact, that's the least it'll be doing. I would like to swap to 3.42's some point, just don't know when.

 

[donjetman]

I would like to swap to 3.42's some point, just don't know when.

I'm sure someone here would trade their 3.42s for your 4.10s

 

[strokersace]

Well I haven't gotten very far yet. Still waiting for the block to come back from the machine shop. I had parts picked out and about to pull the trigger, but decided to wait to see if the block needed bored or not. Still need to get with Blackbear regardless...

Between the delay at the machine shop and starting a new job a couple weeks ago, I haven't had much time to even think about this thing!

 

[strokersace]

Feeling pretty defeated, but not completely ready to throw in the towel just yet. Machine shop called last week so I swung by after work. Good news is a light hone cleaned up the cylinders.

Bad news in that the stock pistons and rings (160K + miles) "have some play". I don't know exactly how much, nor do I know with certainty that new rings would tighten things up. To make sure it's 100%, would likely need to punch them out one size up with new pistons. Then the OTHER BAD NEWS... He asks "oh, how does the crank look? Specifically the #3 main where there thrust bearing is." He then show me the rearmost bearing surface where you can see that the crank has had contact with the block. Noticed it after honing it. The aluminum has a slight lip from the rear main cap rubbing. He says that the bearing surface can be cleaned up and that the block is good. However, after inspection of my crankshaft that night, it has bad wear on #3 and allowed the crank to walk forward.

SO>>> If I'm at a crossroad...

1. Do I continue with the 6.2 and just do a full ground up with new rotating assembly, bored, etc.? If I go that far, I might as well in new valves and have the heads gone through since everything else will be new. Good to have the injectors gone through as well or replace??? RECOMMENDATIONS on manufacturers of rotating assembles to look for OR stay away from?

2. Sell the 6.2 parts, take the loss, and move on redoing the 6.0 in it now? Engine has 190k +, so there's always the wildcard if it having issues as well beyond the cam/stuck lifter. It's the cheaper option (assuming no cylinder wall / rotating assembly issue). And at this point, probably the most sane path! It won't have the power/torque of the 6.2 but will definitely be better than it was stock. IF I go this route, can I and would there be any real performance benefit to running the L9H injectors and fuel pump in the 6.0???

Any guidance and help would be much appreciated. I'm sure there are threads all over the forum that I haven't found yet in my searches. I see BTR and TX Speed have cranks, pistons, and complete rotating assembles with rods. Not sure what's best. Same with master rebuild kits. In google searching, there are some out there, most include pistons. But not getting many warm fuzzies with ebay or amazon kits... I need to make a decision this week one way or the other and plow forward.

 

[PatDTN]

I vote 6.0

 

[strokersace]

I vote 6.0

I'm leaning heavily towards that as well. I don't want to, but am cutting my losses with the 6.2. There's just been bad vibes all along with it, and I just don't have a good feeling about it continuing.

Think I'm just going to put a stage 2, non-DOD/VVT cam in the 6.0, headers, L9H injectors and fuel pump, have BB tune it, and truck on. I won't have the horsetorques that I was hoping, but it'll still be a massive improvement over bone stock.

 

[swathdiver]

Why not use the other motor's crank? FYI new sleeves are like $36 from Melling.

Using the L9H injectors on the L76 opens your tuning and power window including the ability to now run ethanol. These motors love E85.

 

[strokersace]

Why not use the other motor's crank? FYI new sleeves are like $36 from Melling.

Using the L9H injectors on the L76 opens your tuning and power window including the ability to now run ethanol. These motors love E85.

I have considered it. They use the same crankshaft. I did not know that about sleeves. I'll research that. $288 plus new rings, using the 6.0 crank (assuming it's good) and current 6.2 pistons is considerably cheaper. Now, I'd still have the rebuild kit (bearings, gaskets, etc.) and am still trying to find a quality one. If I don't open up the bottom end of the 6.0, then I'd save on the rebuild kit and only focus on the top end. I have some more thoughts/research to do for sure. Here it is the end of the week and I'm no closer to making a decision!

I feel like a teenage girl picking out clothes to wear. Every time I decide this is the direction I'm going, I change my mind. Last night I decided, but I'm waffling!