Hello Everyone. I've been a long time lurker(love that search function!) but haven't ever created an account and posted. I'm looking for some advice, so I figured now is a good time to post.

Here's kind of the long backstory...
I'm helping my buddy with his 07 GMC Sierra 1500 MAX, that has the 6.0 L76 Engine. About 6 months ago it had a DOD lifter that collapsed. I did some research and found info about the DOD delete. Ordered up a kit from Texas Speed and got it all installed(new lifters, valley plate, lifter holders, timing chain tensioner). Got the truck back together and it seemed to have good power, but at idle it was really rough, must be a misfire but it doesn't throw any codes. Also, the cylinders that had DOD had way less compression PSI than the non-DOD cylinders. Off the top of my head about 20 pounds or so.

So I hopped back on the internet and did more research, to see that it seems like you can't use the stock cam. My buddy had an L92 cam that he said came out of an Escalade that had the VVT(which this L76 does), but no DOD. It does have the oiling groove on the second(?) cam groove. I put that cam in, truck ran the same.

The other big concern is the engine has really low oil pressure. Now I didn't drive the truck before the DOD lifter collapse, so I don't know if me changing things is a direct result. The motor basically has the 10PSI per 1,000RPM. My 5.3 LS in my 00' Sierra always has between 40-60PSI depending on temp and RPMS. Isn't this way too low? My buddy told me that if he drove the truck for about 20 miles on the freeway(extended period of higher rpm's), it developed an incredibly bad lifter noise which has progressively gotten worse. I'm thinking because of the low oil pressure, the engine ate a lifter.

So here's where its at as of today. Yesterday, we pulled the engine. Decided to do a rebuild to make the engine fresh. Its sitting as a long block. I haven't pulled the cam out yet to see if ate a lifter.

Still with me?

Here's my questions/concerns:
1. Is the L92 cam causing the misfires?
2. What's causing the low oil pressure?
3. What's causing the low compression PSI?
4. Do I need a different cam?
5. Do I need to replace the oil pump and/or relief valve?


Here's some of the other pages I was trying to pull info from:
https://ls1tech.com/forums/generatio...it-help-2.html

http://www.ls2.com/forums/showthread...amshaft/page2&

Now that I've typed all this up and re-read those threads...sorta seems like this L92 cam is also DOD and might be causing me all my problems.

HUGE thank you to everybody. This website is amazing. I'm just trying to avoid throwing parts and money at this engine.

 

The camshaft is causing the misfiring. The AFM cam has different lift measurements for cylinders with AFM versus those without; the AFM lobes have a higher lift. So replacing the lifters and pushrods to eliminate the AFM, but keeping the AFM camshaft, the higher lift on those affected cylinders is probably keeping the valves open slightly near TDC, bleeding off compression.

And bear in mind the escalade only came equipped with the L92 (non-AFM) between 2007-2009, afterwards it received the L94 which does have AFM. So it's possible your buddy mistakenly thought a 2010+ cam from an escalade was from a L92.

If you installed the non-AFM valley plate correctly (i.e., with all the o-rings in place) then you should not have an internal oil leak. You did mention installing the solid chain tensioner, so you removed the oil pump I assume? A common source of lower oil pressure after a cam swap (when the oil pump is removed) is caused by the o-ring between the pickup tube and the pump, which can get pinched or roll off on one side.

 

Thanks for the reply. I've been researching and calling like crazy trying to figure it out.

I'm going to pull the cam that's in the motor this weekend and get the numbers off it. My buddy said its off a 2008+ Escalade. Once I get the numbers off it I'll be to really see what the heck is going on.

I never actually pulled the oil pump off the sump. I disconnected the entire assembly. But either way, I'll check into that as well and make sure I have good connection there.

 

So, with the DOD cam issue, is there a "mod" for it that keeps the DOD functionality? Is it just crap factory parts, or is it crap execution? Does Comp Cams or the like make a unit that is not prone to failure? I ask because I am considering doing an L76 swap in my '69 Firebird and really want to know if it is ultimately worth it, or for reliability-sake, just going with an LS1/2/3.

 

It appears the DOD not being turned off is more likely the culprit. You can still use the stock vvt cam and just delete the DOD, but normally it is also necessary to change the oil pump as well. With the VVT and DOD the engine needs a significantly larger volume of oil to operate. After you take the DOD off, that need is no longer there.

If you want to keep the VVT we do offer quite a few off shelf and custom cams selections available and we also have VVT delete cams as well. And possible tuning options as well.

Let us know if we can be of more help!