Ok, now that I've snaked you in here, let me explain.

I have a C5, wanting to put a LS3 in, and I found a L92 from a denali on craigslist that is cheaper and had "oil issues." Customer said oil pressure dropped 20psi, and he heard a noise. Mechanic changed oil and filter, said it was fixed, and shipped it. 2 weeks later, same thing. So customer comes in, says he needs truck to be reliable, so without diagnosing, throws a new motor in.

Mechanic specializes in BMW's and isn't too familiar with these motors. I've been reading, but still new. From what I understand, these lifters are notorious for going bad. Which is what I was thinking. So we pull valve covers, and find the #4 cylinder exhaust rocker arm is free moving. Has about 1/2" of travel between resting on pushrod and resting on spring. So we pull the rocker, rocker good. Pushrod not bent.

Then we drop the pan, everything still looks good, no metal bits in the oil, etc. So, we pull the head. Sure enough, cylinder #4 exhaust lifter is collapsed. Won't spring back out. The roller that rides on the camshaft, is rough and not smooth like the others.





So now that we've established that the lifter was not opening the exhaust valve, this brings me to some questions:

If the exhaust valve isn't opening, where is the exhaust gas escaping to? It has to go somewhere. Is it just being compressed and then escaping through the intake? Or would it flow past the piston rings? Is that something to worry about?

The exhaust valve is "crystalized". Is this normal? It looks like it has salt on it, but it doesn't. No other valves had that. And the piston looked completely fine! Is this something to worry about?

Is the failed lifter the cause of the drop in motor oil psi? Or is it the drop in motor oil psi that caused the bad lifter?

Guy is asking $2000, said he would take $1700. I'm thinking $1000. Is his price reasonable? He said he's had multiple calls, no one has showed up until me. And he said I was the first to actually ask about the oil psi issue. So I think he's more inclined to work with me. Time will tell. Is $1700 a good price?

All comments and concerns are appreciated, as I don't really want to buy something that isn't worth it. Thanks!

 

I would think that the lifter went out first. It bounced until it started to cause the roughness you see. This has probably dispersed metal into the engine and opened up some bearing tolerances. That is likely what has killed the oil pressure.

I probably would not purchase this engine unless I were okay with completely rebuilding it.


Concerns? The cam is likely damaged from the lifter as well. My guess is that it ran this way for some time.

 

I agree with Omega.
That is a rebuidable core at this point. I wouldn't just drop a lifter in it and drop it in the car. It will need a full rebuild.
As a core, I wouldn't pay more than $1000 for it.
BTW, I thought Denali's came with the LQ4, LQ9 6.0 and standard trucks came with the L92 5.3s. But I could be wrong.

 

A head job is in as far as the block take a good look at that lifter bore if in good condition great! need new original lifters set check all rod bearings, before removing the rods cups move the rods on the crank up and down if you find one with more play than the others that's a bad bearing at that point I would change all rod bearings and use a new oil pump.

Also remove the trust main bearing cap (the one in the middle) if there's a spun main bearing these will be the one though I doubt it cause when the main bearing is spund oil pressure goes to zero if upon removal and inspection this main cap bearing is good you have a good motor.

Of course a complete desassemble and rebuild will live you with a better motor but that maybe optional as the piston rings are likely still in very good condition.

 

This could be a can of worms for YOU, unless you are able to do all the work yourself and are knowledgeable about the proper way to rebuild an engine. As someone post before, you must determine if you are truly looking at a rebuildable core. If the lifter bore is damaged, this would not be a good candidate to start with. Is the crank good as is, or can it be saved with regrinding it if the bearing have scored it badly. Have any mains bearings seen extreme heat and lead to the main saddles needing to be repaired, if possible with align-boring?
I think you get my concerns here. You need to tear done the engine completely to get a idea if you have something to work with, or it's just a costly gamble.

Good luck..

 

So, I bought the motor. I'm going to take it to the machine shop. He said for $250 he will tear it down and do a full diagnostic on it. Taking a gamble here. I was able to pick up a ls3 intake manifold for cheap as well. Will my ls1 fuel rail and injectors fit on the ls3 manifold? Or will I need to get the ls3 fuel rail and ls3 injectors?

 

Bad gamble man. The injectors will fit in the manifold but the rails will not be correct for the setup. The bolt and mounting locations will sit too high.

 

Ok, well I can always resell the manifold. It's brand new. Shop bought a crate ls3 from gm and then they immediately installed a magnusson supercharger on it. I got the manifold for $100. I looked online and saw various complete assemblies ranging from $400 to $700 so I figured I'd snag the new one. It was local, so why not. LS3 injectors are around $130 for a full set. LS2/LS3 fuel rail is around $200. So all together, new manifold, new fuel rail, and new injectors for the cost of a used assembly doesn't sound too bad to me.

I realize there are other parts I still need as well, but you know what I mean. I rather pay a little more for new anyways.

 

That motor looks like it has displacement on demand or DOD (or “Active Fuel Management”, as it is called in some apllications), so it will have 8 lifters that can be shut down to make the engine run in 4 and 6 cylinder modes for fuel economy purposes. You can tell that by looking at the valley cover, which in this case is a LOMA (lifter oil management assembly) which controls the activation/deactivation of the DOD lifters. These DOD lifters are famously troublesome, which is why most people eliminate them with a DOD delete kit, which is fairly cheap and easily to obtain from vendors like BTR. It sounds like one of the DOD exhaust lifters collapsed. This would’ve cause the noise, since the rocker will be slapping around if the lifter collapsed. This wouldn’t necessarily hurt the motor, and if exhaust gas doesn’t move out of the cylinder, then that cylinder won’t scavenge and air won’t flow into it.
BTW: I didn’t know that the L92 also came with DOD. My 2008 Denali doesn’t have that, but maybe they added it later?
If it’s a L92, it will have VVT (variable valve timing), which means it will have a special camshaft with an active phaser instead of a cam gear that moves timing around as dictated by the tune. This isn’t a bad feature per se, and there are aftermarket VVT cams now available, but this can be a bitch to tune (ask me how I know). You can delete this feature as well with a cam and cam gear change and the requisite tuning.
Both of these features (DOD and VVT) utilize controlled oil flow/pressure to active, and the L92 have been reported to have oil pump issues, so the low oil pressure might have been caused by that rather than any bearing damage.
Basically, what you have is the same thing as an L99, which is the 6.2 that comes with the Automatic version of 5th Gen Camaro. Basically, it’s a LS3 with Active Fuel Management. The only difference in the heads is that the LS3 comes with lighter hollow valves. But don’t make that worry you, I’ve turned the L92 in my truck over 7000 RPM more times than I can count, and it’s still going.
I would recommend that you buy a complete VVT/DOD delete kit from BTR (link below), with a mild cam, and I would throw a new LS3 or Melling oil pump on it, throw the LS3 manifold on it and enjoy!
https://www.briantooleyracing.com/bt...elete-kit.html

 

What about that exhaust valve? Is that normal, does it look weird to anyone?