Engine Swap to stroked 6.0 (408) and general vehicle refurbishment

[Chooko]

At long last, I was able to work on the Tahoe today!

I recently started a new job, and I've been living in a hotel since the end of March, and away from home, so obviously unable to do any work. Today I installed the new head unit, and got the wires run most of the way to the back for the rear view camera that I'll be installing at some point in the near future. It looks great, and sounds even better. Wireless Carplay is worth ALL the effort. While I was in there I also added a bunch of acoustic foam, and more Killlmat under the dash. In particular I Killmat'd the back side of the panel that's at your knees when you drive. Hopefully all this sound deadening is worth it.

Once that was done, I jacked the Tahoe up again, got underneath it (wearing ear protection!) and had my wife start it several times trying to verify where the oil leak was coming from. I noticed some leaking around the %^&*&%ing adapter that you have to use with the Milodon oil pan. I tightened all of those bolts up a couple of more times, and finally got that to start leak, and I thought for a few minutes that maybe I was going to get lucky and not have to replace the main seal. Alas, it was not to be. It started ******* oil all over the place again once it got hot and I knew that I'd be pulling the transmission. I got to work, and like most things that you do for a second time, it went pretty smoothly. I even managed to get all of the bellhousing bolts without pulling off the intake manifold. I wasn't to bad when I let the engine/transmission hang down and back, and then used about 3 feet of extensions to get tot he top bolts. Once it was out, i pulled the flex plate, and could see that, sure enough, the rear main was not square (round?) on the crank snout. I'm sure that the plate that holds it got pulled slightly as I #$%^'d with that #$%^ing Milodon adapter which bolts into it from below and through the flange of the oil pan. Tomorrow I'll be installing a new seal, with the tool holding the plate in place as I tighten the @#$%ing Milodon adapter. Then I'm going to put everything together, and see what I'm deaing with.

A couple of questions:

1. Is there any way to test the seal before I put everything back together? I'd like to start it with the transmission pulled, and verify that the seal is holding. But I'm not sure if the car will even start, or if there is some other reason why that isn't a good idea?

2. My fans aren't coming on. I really don't know why because they were working great before I pulled the car apart. When I installed the new tune in HPtuners, and started the car for the first time, it appeared to me that the fans were being commanded to on, so I don't think its the tune. What is the best way to troubleshoot/fault isolate the fans?

3. We started the car several times over the course of about 45 minutes, and it got up to 210 degrees on the coolant temp. Then I gave it a solid hour or more to cool off before i started working on it. The headers were cool, the oil pan was cool, but the starter was so hot I could barely touch it. I managed to hold onto it long enough to get the bolts out, and get the connectors on the back off, but it was HOT! WAY hotter than I'd expect for a starter, really ever, and certainly after the amount of cool off time I gave it. I had only disconnected the battery a couple of minutes before I pulled the starter, and the heat of it made me suspicious that the starter was drawing current all the time, just sitting there, but on the other hand the car just sat for 2 months and the battery was good, so I don't think anything has been drawing that shouldn't. The starter is an aftermarket MSD. Anyone ever experienced this? Does it seem normal?

 

[Just Fishing]

For the tune,
If it has never been done.
Select write entire.
It's not the default, and it takes a very long time vs the default.

When I did that, the change was noticeable.
Like some fields didn't get written before.

I hear that's only needed one time after unlocking the ecm...

 

[iamdub]

At long last, I was able to work on the Tahoe today!

I recently started a new job, and I've been living in a hotel since the end of March, and away from home, so obviously unable to do any work. Today I installed the new head unit, and got the wires run most of the way to the back for the rear view camera that I'll be installing at some point in the near future. It looks great, and sounds even better. Wireless Carplay is worth ALL the effort. While I was in there I also added a bunch of acoustic foam, and more Killlmat under the dash. In particular I Killmat'd the back side of the panel that's at your knees when you drive. Hopefully all this sound deadening is worth it.

Once that was done, I jacked the Tahoe up again, got underneath it (wearing ear protection!) and had my wife start it several times trying to verify where the oil leak was coming from. I noticed some leaking around the %^&*&%ing adapter that you have to use with the Milodon oil pan. I tightened all of those bolts up a couple of more times, and finally got that to start leak, and I thought for a few minutes that maybe I was going to get lucky and not have to replace the main seal. Alas, it was not to be. It started ******* oil all over the place again once it got hot and I knew that I'd be pulling the transmission. I got to work, and like most things that you do for a second time, it went pretty smoothly. I even managed to get all of the bellhousing bolts without pulling off the intake manifold. I wasn't to bad when I let the engine/transmission hang down and back, and then used about 3 feet of extensions to get tot he top bolts. Once it was out, i pulled the flex plate, and could see that, sure enough, the rear main was not square (round?) on the crank snout. I'm sure that the plate that holds it got pulled slightly as I #$%^'d with that #$%^ing Milodon adapter which bolts into it from below and through the flange of the oil pan. Tomorrow I'll be installing a new seal, with the tool holding the plate in place as I tighten the @#$%ing Milodon adapter. Then I'm going to put everything together, and see what I'm deaing with.

A couple of questions:

1. Is there any way to test the seal before I put everything back together? I'd like to start it with the transmission pulled, and verify that the seal is holding. But I'm not sure if the car will even start, or if there is some other reason why that isn't a good idea?

2. My fans aren't coming on. I really don't know why because they were working great before I pulled the car apart. When I installed the new tune in HPtuners, and started the car for the first time, it appeared to me that the fans were being commanded to on, so I don't think its the tune. What is the best way to troubleshoot/fault isolate the fans?

3. We started the car several times over the course of about 45 minutes, and it got up to 210 degrees on the coolant temp. Then I gave it a solid hour or more to cool off before i started working on it. The headers were cool, the oil pan was cool, but the starter was so hot I could barely touch it. I managed to hold onto it long enough to get the bolts out, and get the connectors on the back off, but it was HOT! WAY hotter than I'd expect for a starter, really ever, and certainly after the amount of cool off time I gave it. I had only disconnected the battery a couple of minutes before I pulled the starter, and the heat of it made me suspicious that the starter was drawing current all the time, just sitting there, but on the other hand the car just sat for 2 months and the battery was good, so I don't think anything has been drawing that shouldn't. The starter is an aftermarket MSD. Anyone ever experienced this? Does it seem normal?

It's been a while so I don't remember- what's the purpose of the Milodon oil pan? The stock one is a structural part of the lower end and is machined on its adjoining surfaces to tight tolerances. I'm wondering if there's a defect in the fabrication or even the design of the Milodon.

I'm also wondering if your starter was stuck engaged and being spun the whole time by the engine.

 

[Chooko]

For the tune,
If it has never been done.
Select write entire.
It's not the default, and it takes a very long time vs the default.

When I did that, the change was noticeable.
Like some fields didn't get written before.

I hear that's only needed one time after unlocking the ecm...

Hhmmm, I'll verify that my tune file looks like it was copied properly.

 

[Chooko]

It's been a while so I don't remember- what's the purpose of the Milodon oil pan? The stock one is a structural part of the lower end and is machined on its adjoining surfaces to tight tolerances. I'm wondering if there's a defect in the fabrication or even the design of the Milodon.

I'm also wondering if your starter was stuck engaged and being spun the whole time by the engine.

Well, the purpose of the Milodon oil pan is that the stock one was filthy and my wife said "you can't put that on the new engine" and I said "I'm going to clean it first" and then she gave me a certain look and I went inside to buy a new, clean, oil pan. And since I was getting a new one anyway...I might as well get the fancy one with the baffles and extra capacity, and the cool gold color. And honestly, I like the pan. Its the dipstick and the oil filter adapter that you MUST use with the pan that are the issues. The adapter doesnt use normal bolts. You have to use a hex bit and one of them is located in a spot where there is just NOT ENOUGH CLEARANCE to get any reasonable tool in there, where as if they were normal bolts it wouldn't be a big deal to get a wrench or maybe even a short socket on the fastener. Very frustrating for the price. And when I say "in a spot" I mean in relation to the oil pan, Milodon's own product. So I'm forced to use their adapter, and the fasteners are garbage when attaching their fastener to their pan. Its ALL within their control, and is a poor design.

Rant over.

It doesn't mate to the block the way the stock one did. However, that isn't structural I don't think. I think its more of a dust seal. I even asked CircleD, who built the transmission, and they said it was good to go with the Milodon pan.

I had to start the car a number of times today, and I think that you are on to something with the starter staying engaged and running with the engine. So there is ANOTHER thing to add to the lsit to fix before this car is truly ready for the street.

 

[Chooko]

Today I got the rear main swapped and fitted, with a high degree of confidence that its correct this time (hope I don't jinx myself). I got the transmission back in, and then tinkered with the temperature for a while. It turned out that the fans actually were working. I'm not sure how I missed it before. But the car was still overheating, and the air coming off the fans was not hot at all. Eventually I decided that the cooling system might have air in the high points, so I pulled off the upper radiator hose and put water in that way. It took a fair bit, and I kept filling until the water started coming back out of the radiator where the hose was off. After that...viola! The fan air started to get warm, and the temperature on both the gauge and HPtuners stayed right at 210. So great. But whats not great is the car is smoking pretty bad. I started it a number of times today working through this, and it didn't smoke in the morning, but it started this evening, and it doesn't seem to be letting up. It's currently on Maxima break-in oil, on the initial tune (before data logging and refinement), has some sections of new pipe in the exhaust system, and has no cats until I can get it to an exhaust shop. I'm sure that all of those could contribute to an engine smoking. Still, I feel like this is a bit excessive:

Its white, but doesn't smell like burning coolant. It doesn't smell like much at all except exhaust.

Thoughts?

 

[Tonyrodz]

Today I got the rear main swapped and fitted, with a high degree of confidence that its correct this time (hope I don't jinx myself). I got the transmission back in, and then tinkered with the temperature for a while. It turned out that the fans actually were working. I'm not sure how I missed it before. But the car was still overheating, and the air coming off the fans was not hot at all. Eventually I decided that the cooling system might have air in the high points, so I pulled off the upper radiator hose and put water in that way. It took a fair bit, and I kept filling until the water started coming back out of the radiator where the hose was off. After that...viola! The fan air started to get warm, and the temperature on both the gauge and HPtuners stayed right at 210. So great. But whats not great is the car is smoking pretty bad. I started it a number of times today working through this, and it didn't smoke in the morning, but it started this evening, and it doesn't seem to be letting up. It's currently on Maxima break-in oil, on the initial tune (before data logging and refinement), has some sections of new pipe in the exhaust system, and has no cats until I can get it to an exhaust shop. I'm sure that all of those could contribute to an engine smoking. Still, I feel like this is a bit excessive:

Its white, but doesn't smell like burning coolant. It doesn't smell like much at all except exhaust.

Thoughts?

Sounds good. Does it smoke when it's warmed up? Maybe because there's no cats? Mine does the same thing when it's cold, til it warms up. Also could be your more aggressive then stock cam. I have long tubes with no cats. Btw--mine is an 03 with a cammed 6.0.

 

[Just Fishing]

Sounds good. Does it smoke when it's warmed up? Maybe because there's no cats? Mine does the same thing when it's cold, til it warms up. Also could be your more aggressive then stock cam. I have long tubes with no cats. Btw--mine is an 03 with a cammed 6.0.

I noticed mine doing that today while I was at my little hole of desert.
I set my phone to see if it could capture it, and if it got worse when i revved it.

I got water spewing out in the video.

ETA: Watched again in full screen.
Running a little rich maybe?
Do you have a wideband setup?

 

[Chooko]

Sounds good. Does it smoke when it's warmed up? Maybe because there's no cats? Mine does the same thing when it's cold, til it warms up. Also could be your more aggressive then stock cam. I have long tubes with no cats. Btw--mine is an 03 with a cammed 6.0.

Yes, it smokes when warmed up. In fact in that video it was at 210 on the gauge. I'm going to check it in the morning, but if anything I'd say it smoked less when cold.

I never thought of it being the cam. Thats interesting. I HOPE that's not the issue as I really don't want to change the cam, and I want this smoking to stop.

 

[Chooko]

I noticed mine doing that today while I was at my little hole of desert.
I set my phone to see if it could capture it, and if it got worse when i revved it.

I got water spewing out in the video.

ETA: Watched again in full screen.
Running a little rich maybe?
Do you have a wideband setup?

No wideband. It could possibly be rich as it is on an initial tune. But I thought it would be a darker color smoke if it were rich? I'll get a video in the morning in light so the color of the smoke is more clear.

 

[Just Fishing]

No wideband. It could possibly be rich as it is on an initial tune. But I thought it would be a darker color smoke if it were rich? I'll get a video in the morning in light so the color of the smoke is more clear.

Nearly white colored smoke exhaust smell from my vette if it's too rich.
Vette is exept from kitties

 

[Chooko]

Ok, after looking the car over today more closely, there is definitely oil in the exhaust. There is a coolant leak too, which I believe is coming from the rear steam crossover. I'm probably going to pull the intake, and maybe just block off the rear steam crossover. Whatever the case, I am less concerned about the coolant leak as I think it is a nuisance.

The smoke is definitely being caused by oil. Its windy here today so the color is hard to see, but I took apart a portion of my bolt-together Y-Pipe, and oil started coming out from the joint, and was inside the pipe.

Here is my theory...I am running aftermarket valve covers. The driver side one has a nipple for the PCV hose, but it is not in the factory orientation so i cut the factory line and spliced it with rubber hose. It has a baffle inside, but in hind sight I don't think there is a valve in there. I think its just a direct line from inside the head, through the PCV nipple, and into the top of the intake. I pulled the hose off the intake and it had a lot of oil on it. I pulled it off the nipple, and oil dripped out from the end of the hose. I guess I'm not entirely certain how the PCV valve functions. I know I had one go bad and cause the engine to smoke several years ago, but my assumption was that it stuck closed, although now that I think about it that probably wouldn't cause smoking. At any rate, would a complete lack of a PCV valve cause the smoking I am seeing?

 

[iamdub]

Ok, after looking the car over today more closely, there is definitely oil in the exhaust. There is a coolant leak too, which I believe is coming from the rear steam crossover. I'm probably going to pull the intake, and maybe just block off the rear steam crossover. Whatever the case, I am less concerned about the coolant leak as I think it is a nuisance.

The smoke is definitely being caused by oil. Its windy here today so the color is hard to see, but I took apart a portion of my bolt-together Y-Pipe, and oil started coming out from the joint, and was inside the pipe.

Here is my theory...I am running aftermarket valve covers. The driver side one has a nipple for the PCV hose, but it is not in the factory orientation so i cut the factory line and spliced it with rubber hose. It has a baffle inside, but in hind sight I don't think there is a valve in there. I think its just a direct line from inside the head, through the PCV nipple, and into the top of the intake. I pulled the hose off the intake and it had a lot of oil on it. I pulled it off the nipple, and oil dripped out from the end of the hose. I guess I'm not entirely certain how the PCV valve functions. I know I had one go bad and cause the engine to smoke several years ago, but my assumption was that it stuck closed, although now that I think about it that probably wouldn't cause smoking. At any rate, would a complete lack of a PCV valve cause the smoking I am seeing?

Aside from the some of the very first LS engines, these don't have a PCV valve. They have a nipple with an orifice of a specific diameter. The way the PCV system flows is: Clean air is pulled from the intake tube, after the air filter and after the MAF. It goes into the passenger side valve cover and down into the crankscase. The tube running from the top center of the intake manifold to the nipple/PCV port on the driver side valve cover uses intake manifold vacuum to suck the PCV vapors out through the driver side head. The stock valve cover has a baffle to help separate the oil from the PCV air flow.

To have excess oil in the PCV system, either you have an obscene amount of air volume overfilling the crankcase or oil is filling the valve cover (not draining back efficiently enough) or an obscene amount of manifold vacuum. I'd rule out the manifold vacuum since the cam would reduce this from the factory amount.

I'm not saying the valve covers are your problem. But, things like this and the oil pan stuff are why I don't see the point of race parts on a street vehicle if they're not functionally necessary. They could do more harm than good. For example, a race engine with a huge cam and/or boost wouldn't have any use for the stock PCV system. They might even run a vacuum pump to vacate the crankcase.

Something in yours is pushing oil into the PCV. I hope it's just the heads filling with oil and not the crankcase being over-pressured by blowby. Although, that's usually only a problem at higher RPM. Are you sure your oil level is correct?

 

[donjetman]

Ok, after looking the car over today more closely, there is definitely oil in the exhaust. There is a coolant leak too, which I believe is coming from the rear steam crossover. I'm probably going to pull the intake, and maybe just block off the rear steam crossover. Whatever the case, I am less concerned about the coolant leak as I think it is a nuisance.

The smoke is definitely being caused by oil. Its windy here today so the color is hard to see, but I took apart a portion of my bolt-together Y-Pipe, and oil started coming out from the joint, and was inside the pipe.

Here is my theory...I am running aftermarket valve covers. The driver side one has a nipple for the PCV hose, but it is not in the factory orientation so i cut the factory line and spliced it with rubber hose. It has a baffle inside, but in hind sight I don't think there is a valve in there. I think its just a direct line from inside the head, through the PCV nipple, and into the top of the intake. I pulled the hose off the intake and it had a lot of oil on it. I pulled it off the nipple, and oil dripped out from the end of the hose. I guess I'm not entirely certain how the PCV valve functions. I know I had one go bad and cause the engine to smoke several years ago, but my assumption was that it stuck closed, although now that I think about it that probably wouldn't cause smoking. At any rate, would a complete lack of a PCV valve cause the smoking I am seeing?

Sometime around 2011 or later, Gm came out with a service bulletin to install their new improved driverside vc, pt#12570427, on various GM vehicles ranging from yr models 2007-2015. The problem was oil being sucked out of the valve cover area and into the intake manifold causing oil consumption and/or stuck rings.

This was a problem on my 07 Yukon Denali L92 6.2L when I bought it in 2018. Per the advice of forumites here, I installed the improved vc, and an inexpensive catch can plumbed into the vacuum line between the vc and intake.

40k miles & 3 yrs later, no more oil consuption and my catch can doesn't catch mush of anything. If it ever does start, I'll know "HOUSTON, WE HAVE A PROBLEM".

 

[donjetman]

Original top, improved bottom

 

[donjetman]

My cheap catch can

 

[Chooko]

Its time for another update...

I installed a Morosso Catch Can that is marketed specifically for these vehicles (really just means that it came with a bracket that lines up with some factory bolt holes), and also installed a valve in the line going from the valve cover to the intake. No more smoke! I'm sure its the catch can doing all the work of stopping the smoke, but either way its good to go.

I've been chasing down other minor issues, such as finding the correct size stretch belt to work with the non-stock harmonic dampener, dealing with a few small leaks, and doing data logging in HPtuners for the engine tuner. I also got the car to the exhaust shop and got a proper Y-pipe with catalytic converters installed. The exhaust is buttoned up, and it sounds AWESOME!. Its not loud at all at idle, and inside the car you might not even notice that its not stock. But it sounds amazing as the RPM's come up. And goodness has this thing got a lot of power.

Today I did the final plumbing of the external transmission cooler and the stock in radiator cooler with -6AN hose and fittings, and I think it came out pretty well, but I damaged the terminals on the inline thermostat in the process so I currently have the fan for the transmission cooler jumped, and I have to unplug it when I shut the car off or it'll just run until the battery goes dead. Not to worry though because I ordered a new one today and its a super easy fix once the part is in hand. I also think I have FINALLY fixed all of the transmission cooler line leaks. There were only a couple, and they were minor, but I think they are good now.

Speaking of leaks though...the front crank seal is weeping oil. Its just a very minor leak, but obviously not something I want on my brand new engine. It wouldnt be that big of a deal except that I had a really hard time getting the harmonic balancer keyed properly on the engine stand, so I'm REALLY not looking forward to trying to put it back on with the engine in the car. I think that's the last mechanical thing that I have to fix for this swap to be considered complete, although there will be more tuning work once I put a few thousand miles on it, and I have other projects in the interior and suspension.

I'll try to get some pictures and maybe some video up tomorrow.

 

[Chooko]

I got the front main seal fixed, and also (finally) tracked down and fixed the transmission line leak. I don't think it'll ever be truly done, but the Tahoe is now completely drive-able, and a real blast on the road. I still have a list of things in my head that I'd like to do to it in the future, but for now I think I'll close this with a video.

 

[Rocket Man]

I got the front main seal fixed, and also (finally) tracked down and fixed the transmission line leak. I don't think it'll ever be truly done, but the Tahoe is now completely drive-able, and a real blast on the road. I still have a list of things in my head that I'd like to do to it in the future, but for now I think I'll close this with a video.

Sounds awesome, congrats on getting things buttoned up.

 

[Chooko]

Thanks Rocket Man! She's running great although, as with most projects like this, I am already looking at doing some more things to the Tahoe. Specifically, I think I need to upgrade the cooling system. I think an aftermarket radiator and fan set up is next. It also needs tires, and I think I am going to upgrade wheels while I'm at it. I'll post pictures of this stuff when it happens. For now, here are a couple of more start videos just because I think it sounds badass: