2012 Yukon XL Denali 6.2L Cam Swap Thread

[wjburken]

Just saw this...

My recommendation would be to have the machine shop pull a vacuum on the valves to make sure they are all sealing properly. If they are sealing well then there is no need to lap the valves.

I always have them Magnaflux the heads to make sure they aren't cracked BUT I have always pulled heads because of blown head gaskets.

By Magnaflux, you mean dye penetrant testing, not mag particle right? I think his heads are aluminum so would need to use dye penetrant to check for cracks.

 

[kbuskill]

By Magnaflux, you mean dye penetrant testing, not mag particle right? I think his heads are aluminum so would need to use dye penetrant to check for cracks.

I guess thats what I mean... my machine shop knows what I mean... lol

Seriously though, I have never really researched the process, I have always just dropped them off and had them check for cracks. However they do it... maybe its black magic... lol

 

[wjburken]

I guess thats what I mean... my machine shop knows what I mean... lol

Seriously though, I have never really researched the process, I have always just dropped them off and had them check for cracks. However they do it... maybe its black magic... lol

Only reason I know is I used to be the Engineering Manager for Magnaflux designing their mag particle and penetrant equipment.

 

[Geotrash]

Thanks for the additional guidance, gents. Work has been busy (the usual Q4 madness), so have been only making slow progress. Procrastinating about dropping the oil pan, too. On one shoulder, there's a red angel that says "You really only need to drop it enough to get the pickup tube bolt out." And on my other shoulder is a blue angel saying in my dad's voice: "Remove the pan fully so you can do the job right, clean it out and get a new pan gasket in there." Of course, that means dropping the cross member, lowering the steering rack and the front diff. All doable, just a PITA.

 

[kbuskill]

Thanks for the additional guidance, gents. Work has been busy (the usual Q4 madness), so have been only making slow progress. Procrastinating about dropping the oil pan, too. On one shoulder, there's a red angel that says "You really only need to drop it enough to get the pickup tube bolt out." And on my other shoulder is a blue angel saying in my dad's voice: "Remove the pan fully so you can do the job right, clean it out and get a new pan gasket in there." Of course, that means dropping the cross member, lowering the steering rack and the front diff. All doable, just a PITA.

If you still have the intake off you can unbolt the engine mounts and jack the engine up enough to remove the oil pan without dropping the steering rack.

If the heads are still off you will have even more clearance on the firewall.

There are spots cast into the block that stick out on either side that you can jack from or if you have an engine hoist/cherry picker you can lift it from above.

This is how I did mine on the Burb but mine is 2wd so yours may require dropping the front diff slightly to clear.

Do it right or do it twice... lol

 

[Geotrash]

If you still have the intake off you can unbolt the engine mounts and jack the engine up enough to remove the oil pan without dropping the steering rack.

If the heads are still off you will have even more clearance on the firewall.

There are spots cast into the block that stick out on either side that you can jack from or if you have an engine hoist/cherry picker you can lift it from above.

This is how I did mine on the Burb but mine is 2wd so yours may require dropping the front diff slightly to clear.

Do it right or do it twice... lol

I like that idea because I can also do the motor mounts at the same time. Thank you.

 

[Snowbound]

Curious as to where the magic number of .0025” came from? Drop the heads off and tell them to surface them to under a 40Ra and they will make sure they are straight and clean. Most MLS head gaskets can handle a surface that is 60-70Ra microinches but some require cleaner 30-50Ra. The cleaner is always better rule applies here too. No real need to check for cracks since you didn’t have any issues. Valves shouldn’t need any work either. Even the umbrella seals should be fine but if you want to have them changed while out, I get it. Trunion upgrade is always a good thing and that’s about all I would really recommend.
Turn your intake upside down and see how much oil comes out. That will tell ya if you need to do the catch can like everyone else does.
Take your time, mark the bolts once torqued to spec, be sure everything is clean, blah, blah, blah! You got this, it’s about as straight forward as it gets. Oil pan sucks though. No way to sugar coat it. I hate doing them and I feel for ya. Not that it’s hard just sucks being on your back working around Jack stands and cherry picker legs. Keep the progress coming. Nice job so far.


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[Geotrash]

Thank you, snowbound. I was just logging in to give an update and saw your message so I’m grateful.

Finally got the oil pan out this evening and it wasn’t as bad as I thought it would be. I dropped the passenger side of the differential, the stabilizer bar, and the crossmember and steering rack. An air impact wrench makes short work of such things.

Thanks for the advice on the heads. The .0025 number came from another member here who suggested it to get the quash a little tighter for better combustion. Already got them back from the shop, cleaned up and ready to go. Putting the trunnion upgrade kit in this week, and new seals. Valves are all in good shape as well. That’ll about do it and she’ll be ready to start going back together. If I’m lucky, I’ll have her up and running by the weekend.


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[JTRATX]

Are you doing headers/new exhaust, or just re using OEM?

 

[Geotrash]

Are you doing headers/new exhaust, or just re using OEM?

Just reusing OEM


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