2008 Suburban Engine Swap - 6.0 to 6.2

[Geotrash]

If I'm I'm opening it up at all, I'm highly considering a cam and doing lifters at the same time. Curious though (this is something I haven't researched much at all), you went with a non-VVT cam verses doing a larger VVT cam from Gwatney like you mentioned. Thoughts/reasons? I've been eyeballing the Gwatney stage 1 low lift vvt cam if I open it up that far.

I went with the non-VVT cam for a handful of reasons:

1/ No power loss over stock down low. I did hours (days?) worth of research to determine how much power I might lose (over the factory cam) on the low end with a 3-bolt cam, and determined that it would be essentially zero loss and more likely a little gain over stock with a 3-bolt truck cam designed for the 6.2. Of course the 3-bolt cam would still provide great gains in the towing RPM ranges, which is what I cared about. If I kept VVT with a new cam, I would gain some on the low end, but I decided that the other factors below outweighed that for me. Subjectively and according the butt dyno, I'm super happy with the power on this cam through the rev range. I have an '07 XL Denali with the L92 and stock VVT cam to compare it with regularly, and the '12 with the 3-bolt cam makes me smile every time I drive it. Towing power is way up. I can maintain 55-60 in 3rd on grades that used to require a drop into 2nd and 45 mph with the stock cam.

2/ Reliability and Durability. My top priority after towing power was reliability/durability. Dropping the VVT eliminated a potential source of reliability issues, and it enabled me to go with the wedge style timing chain tensioner, which eliminated a source of durability issues. Both the VVT and the spring-style tensioner are generally reliable and long-lasting, but problems still occur. The plastic guides on the spring tensioner have been known to fail and fall into the oil pan.

3/ Less hassle in the install and setup. Larger VVT cams require a limiter to prevent valve interference. And torquing the single bolt requires removing the starter to install a flywheel holder. I didn't feel like hassling with either, but with the engine out, it would definitely be easier.

Side note: BTR sells a set of beehive springs that will allow up to .560 lift, so I chose the 'high lift' version of the Cam Motion stage 2 cam (@.553) in order to skip the dual spring requirement and associated top-hat style valve stem seals, yet still get the most power I could under the limit. I'd previously had a set of dual springs with top hats on for a while - all properly installed, and I had 2 of the seals lift off the posts and trigger oil burning. It was a hassle that I didn't want to deal with again.

 

[strokersace]

Welcome to the Forum from NH.

Lots of knowledgeable folks here who freely share their knowledge, experiences, and perspectives. Knowledge is power.

I hope that you will become a participating member in the Forum's discussions.

Pics of the truck, please.

You are already receiving sage advice from the knowledgeable folks on this Forum.

To the experts on this Forum: Any issues with keeping the 4 speed transmission and mating it up to the 6.2 motor?

Thank you for the welcome. Been browsing for a while anyway, finally setup a login, then BAM - stuck lifter!

As for mating the 6.2 to the 4spd, being that it's an M70 verses the 4L60, might help some. In stock form with a tune, I'm hoping/planning on it being able to hold together. But if I put a cam in it, vvt or not, I'm not sure... Would be good to discuss.

I went with the non-VVT cam for a handful of reasons:

1/ No power loss over stock down low. I did hours (days?) worth of research to determine how much power I might lose (over the factory cam) on the low end with a 3-bolt cam, and determined that it would be essentially zero loss and more likely a little gain over stock with a 3-bolt truck cam designed for the 6.2. Of course the 3-bolt cam would still provide great gains in the towing RPM ranges, which is what I cared about. If I kept VVT with a new cam, I would gain some on the low end, but I decided that the other factors below outweighed that for me. Subjectively and according the butt dyno, I'm super happy with the power on this cam through the rev range. I have an '07 XL Denali with the L92 and stock VVT cam to compare it with regularly, and the '12 with the 3-bolt cam makes me smile every time I drive it. Towing power is way up. I can maintain 55-60 in 3rd on grades that used to require a drop into 2nd and 45 mph with the stock cam.

2/ Reliability and Durability. My top priority after towing power was reliability/durability. Dropping the VVT eliminated a potential source of reliability issues, and it enabled me to go with the wedge style timing chain tensioner, which eliminated a source of durability issues. Both the VVT and the spring-style tensioner are generally reliable and long-lasting, but problems still occur. The plastic guides on the spring tensioner have been known to fail and fall into the oil pan.

3/ Less hassle in the install and setup. Larger VVT cams require a limiter to prevent valve interference. And torquing the single bolt requires removing the starter to install a flywheel holder. I didn't feel like hassling with either, but with the engine out, it would definitely be easier.

Side note: BTR sells a set of beehive springs that will allow up to .560 lift, so I chose the 'high lift' version of the Cam Motion stage 2 cam (@.553) in order to skip the dual spring requirement and associated top-hat style valve stem seals, yet still get the most power I could under the limit. I'd previously had a set of dual springs with top hats on for a while - all properly installed, and I had 2 of the seals lift off the posts and trigger oil burning. It was a hassle that I didn't want to deal with again.

I appreciate that information. Compelling for sure! Either way I go, going to try to get the engine picked up tomorrow. If it comes home with me, then the buying of parts begins!

 

[Geotrash]

As for mating the 6.2 to the 4spd, being that it's an M70 verses the 4L60, might help some.

Happy to help. And yes, the M70 is good to 650 hp/tq. so you should be good to go there.

 

[strokersace]

Hoping to go pickup the engine this evening.

In the meantime, here's the rig. When we bought it (sorry, not a great picture and the only one I can find on my phone). Stock wheels, debadged, no running boards.



New wheels. My wife insisted on black, it's not my thing at all, but you can see she won! I chose the tires. Nitto Recon Grapplers. Blacked out the bowties and added boards. I'm going to wrap the handles like the 2015+ models and add side moldings with the chrome strip. I think that will accent the wheels very well since they're black with milled edges.

 

[strokersace]

WELL... hit a bit of a snag. The guy close to me with the L9H has quit responding to phone calls or texts. The ad is still active for the engine, but I cannot get a response from him. Looks like I'm going to have to move on. Dang disappointed since it's so close to me.

Found an L94 down in north Texas close to where my wife is from. It has less than 500 miles on it since deleted and a TSP truck state 2 cam installed. Trying to get in touch with the guy. I obviously have questions as to why it's for sale, right after rebuilding it. At least if if I hauled down there 8 hours to get it, we could see the family.

This whole deal is frustrating. If I cannot find a good 6.2 donor, I'm likely going to yank the 6.0 out to rebuild. Cam, delete, etc.

 

[PatDTN]

If I had to choose again I'd rather have the 6.0. There's no telling how big that extra hit for premium will go and that's every fill up for the life of the truck.

 

[donjetman]

If I had to choose again I'd rather have the 6.0. There's no telling how big that extra hit for premium will go and that's every fill up for the life of the truck.

You can always have it tuned for regular 87 octane?

 

[PatDTN]

You can always have it tuned for regular 87 octane?

I was told you can't but my neighbor reminded me tonight that he know people with 6.2 Yukons that run regular. I think I need to contact Black Bear...

 

[swathdiver]

I was told you can't but my neighbor reminded me tonight that he know people with 6.2 Yukons that run regular. I think I need to contact Black Bear...

He also knows people with broken pistons and rings! LOL

 

[Dustin Jackson]

There are vehicles to be driven if you are economy centric but these are not one of them.