Broken down, toasted engine??

[Dave5Cs]

Are 6V92 also left hands on GM'S?

[Geom]

Hey guys, quick update.

Not a whole lot new to report. The shop folks plan to roll us in Tuesday morning to start looking at things. Their plan right now is to check the aftercooler and see if it's the culprit. I seriously doubt it, and suspect they do as well; but I do think they're trying their best to mange my costs. Plus they'd have to remove the turbo regardless, if that engine was coming out. So pulling the blower is relatively straight-forward from there.

I completely agree that I don't want to throw good money after bad, and at some point there will have to be a stop loss moment where the bleeding of cash has to stop and the beginning of actual fixing starts. It's really difficult for me to guage that point right now. We really don't have enough information to act. So, for now, I'm willing to give these guys the professional deference to do the job and help me reach that point. But I can definitely see how the "desire to know what happened" can overwhelm common sense. So I'm hoping you guys will help me in deciding when that point is near.

For additional clarification,
We do indeed have a 6V92 Turbo.
It is indeed left turning.
We have never had a "heat event", and the hottest the engine has ever been is 200-205 during that one (previously posted) climb in Denver. (After which it cooled right off when we crested the hill). After that I'd been managing heat, by substantially reducing speed (often sub 25mph), and pulling over frequently on long climbs when the temps were getting to the uncomfortable side of 195. Then I installed those 2 radiator fans and that seemed to help a lot.

I do have a question, the front valve cover has a series of serial numbers on it:
Something about a "kit" serial number and an OEM serial number, along with the Turbo serial number. They were able to use the Turbo number to find the part we'd need (back when he suspected the turbo) and that helped them immensely.
Are the other serial numbers usable in the same way -to figure out what's in that engine, who did the rebuild, how it was done, the type/age of block, etc? That might help me decide if I would rather rebuild this engine or replace it. And if so, how would I get that info?

And as far as replacing it (if we do end up there), I'm trying to decide between a "good" old engine (and how to determine what/where that is) vs a rebuilt replacement. I realize opinions will vary wildly here, but I'm looking for your input and thoughts on that anyway; as I try to weigh those options. And at this point, I honestly have no idea where I'd get either option.
This shop only has those goofy right-handed 6v92s 

Anyway, that's all for now. More info coming soon.

[luvrbus]

I don't understand why they do not remove the inspection covers from the air box and pressurized the system to see where the water is coming come or even do a compression test.With it blowing smoke and running rough I say a head problem. 
Hopefully just a gasket set on the head or a injector tube,we won't get into the great antifreeze debate but the wrong antifreeze and not maintaining the system the o-rings just turn to mush and turn loose.
FWIW those tags tell everything about the engine when it was new like a built in parts book sorta 

[Geoff]

If the shop thinks pulling the after cooler is the possible cause of all the engine problems I would have my bus towed out of there.  That mechanic is no two stroke Detroit mechanic.
Like I said, you need to drop the pan, check the crank, and if it's okay, pressure test the cooling system to begin to isolate how the antifreeze is getting in the oil pan. If you remove the after cooler now you won't be able to do a pressure test.

--Geoff

[thomasinnv]

Gotta say I'm with Cliff and Geoff on this one. Don't let them tear into it without putting pressure on the cooling system and pulling the inspection covers.

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[luvrbus]

Are 6V92 also left hands on GM'S?

I don't believe GM ever offered a 6V92 as a option for their intercity buses only in the transit models

[Cary and Don]

Didn't somebody post at one time that there were parts that made a right hand engine left hand? If that was the case, couldn't the parts be switched out from the old engine to the new one?

Don and Cary

[luvrbus]

Cary and Don it's a lot trouble you need to pull the heads to change the cams the oil pump needs changing and then install the GM fan drive, then if the crank is not directional that has to be changed more trouble than it's worth IMO if needs rebuilding go with what you have 

[lostagain]

I would replace/fix what is broken on your current engine, and carry on. Unless you find a replacement engine, new or used, and that is unlikely. It will cost money, but you have to expect to have to spend some money once in a while to keep any vehicle/machine running. Just hope it is not too much. Good luck.

JC

[chessie4905]

You'll be better off pulling and taking engine apart and going over everything. What if you patch it and it goes out two thousand miles down the road with the crank out or a busted piston or liner. You think it is going to cost now/ what about doing it twice? Just bite the bullet now or have it towed to a good two stroke mechanic.

[Iceni John]

Gotta say I'm with Cliff and Geoff on this one. Don't let them tear into it without putting pressure on the cooling system and pulling the inspection covers.

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I just finished today putting a Schrader valve onto my coolant surge tank for this exact reason, so I can easily pressure-test the entire cooling system in the future if I ever need to.   Didn't some 'Hound MCIs have this from the factory?

John

[Scott & Heather]

Latest George?


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[Detroitenginespecialist]

Geom,

If you find out the engine is toast, please give me a call to discuss American Fleet building you a reman'd 6V92.  We build at least 2 or 3 a month.  We use genuine DD parts and we can have it built within 2 days of your order.

I sent you a private message as well.

[Geom]

Alright guys, here's the latest.

Finally got into the shop, sometime this afternoon.
I mentioned the whole pressurizing the cooling system thing. He was heading down that path, but it was clear that water was entering the engine. So before he did that, he wanted to pull the lower exhaust manifold (as there was oil seeping from it that was never there before). 
Upon pulling that, it was obvious what at least one big part of the problem was.
There was a pool of oil inside the manifold. It was also obvious that one of the lower bank cylinders was wet, as where the other two were simply the usually dry sooty black.

That gave the mechanic the info he needed to feel comfortable with pulling the valve cover off, and inspecting the valves and head; as he strongly suspected a cracked head (and possibly cylinder liner among other things).

After he disassembled the valves, it was clear to see what the problem was. We "dropped a valve".
He pulled out the split-in-two-push-rod stay/guide ring (please note that I'm paraphrasing here with the best grasp I have of what's going on). It's a little ring silver colored that surrounds the rod. That, he says likely froze the valve, which likely impacted the piston (and likely perforated it), along with cracking the head (he suspects).

He also noticed significant scarring on the rocker arm (?? the small T looking thing that moves the valves).
A more interesting fact was he noticed the EXACT same type of scarring on all three cylinder rockers. And get this, all of it was on the right hand set of valves. All three on the left side valves looked fine and smooth.
He said that it's possible that one might've been adjusted incorrectly and just eventually just failed.
But with three of them, all on the same side, that tells him someone who had no idea what they were doing adjusted the valves.
And he suspects that they adjusted them as if it was an intake valve instead of treating them all as exhaust.

It was nearing the end of the day, and he didn't want to tear into the actual head until he had a good window of time to finish looking at it.

At this point he suspects the failed parts are

Cracked head
Cracked crown
Cracked sleeve
Perforated piston
Damaged valve and lifter(s)

Parts needed:
Replacement head
Replacement "kit"
Misc gaskets and bits and pieces
Cost: $2200 + Labor
He (shop manager) couldn't estimate the labor as the mechanic had already left, but he will be pulling that info for me in the morning.

I tried to find out if this was likely happening on the top bank as well. He said that the valves are almost certainly horked on the top valve; if whatever moron did the work on the lower bank, also did the same on the upper bank.
The only likely exception is if that head was replaced somehow separately, after the initial rebuild, and it was adjusted incorrectly at that time.
He will be pulling the top-bank valve cover and inspecting that and adjusting correctly as necessary while trying to "repair" whatever valve damage might be up there. As you're likely well aware, that upper bank is a complete PITA to work on. So that'll be interesting.

In addition, there is really no practical way to fully inspect that upper bank because the inspection covers are fully masked by the exhaust manifold. Which would need to be removed. And even then, they may not be accessible.
He had some other ideas on pressure testing the system that he thought could give us a 20K foot view of that bank's health. But without getting to those inspection plates, he wouldn't be able to say with any certainty.

In addition, we emptied that airbox (blowby??) oil reservoir (at the bottom of the engine that we drain periodically) and it was chock full of coolant and very little oil.

So far the only things we've done have been to drain the coolant (what little of it was left. I think something like 4-6 gallons), and he took apart the valve assembly on the lower bank. He has not removed the head, turbo, blower or really anything (beyond removing the coolant pipe to the lower bank, to gain access to fuel lines, etc for removal).

I also mentioned the possible scoring on the crank (that others suggested should be looked at) and whether we should drop the pan. He said we'd eventually get to that, but he doubted the crank would be compromised, unless we ran it for a while with coolant in the system. It was 30 seconds to a minute from thin white trail, to plume, to dead engine.

So that's where we sit right now. The plan is tomorrow for him to finish removing that head. He will inspect the other two cylinders and see how they look. He says that if they look ok (no scorching scarring, etc), then he would feel relatively confident that the damage is just in what he found. If he gets in there and those cylinders also look horked, then he feels pretty confident that the upper bank is in a likely state.

I'm not sure I'm quite there yet, but it's looking more and more preferable that a replacement is the better option?
Even if I drop the $4-5K replacing these parts, considering the jacked up dumbassery he's found so far; I'm not sure if I wouldn't just be back in the same position again in a year or two, or even a week or two.

So I've gotten a quote for a replacement reman'ed engine.
I probably need to get a couple of more quotes (so any volunteers there??) to figure out where the price point actually is.
And I also need to get a quote for an out-of-frame there (but I suspect at their shop rate, that'll be wildly high). 

Thoughts? Suggestions? Considerations? Additional tests?
Please let me know.

Your input is greatly appreciated as always,
George

[luvrbus]

It happens all the time George some idiot will try to adjust the valves with the valve bridges and they drop a valve,sorry I don't have any 6v92 heads left but seems like they are headed in the right direction.
The  in frame is going to cost you around 12 grand and they are going to give you 90 days on labor and 1 year on parts I think you will be fine with a in frame IMO.I think a exchange is going to be a lot more in the end