8V92TA black smoke, low power, overheating?

[Busted Knuckle]

Long story but if Sean's exhaust had been smashed several times, over time, could the resulting back pressure have caused a gasket or something else to weaken producing the symptoms he currently has. 

So my question to the brains here is:  If the exhaust had such a restriction, what would that cause to fail?  Fouled injectors?  Rings?


Another long shot.

And very possibly a good one! As to what I'm as clueless as the rest of the group!

Incidentally, I replaced the secondary fuel filter yesterday -- no change.

Does anyone know if a Davco FuelPro 380 can be "plugged" without the bowl filling most of the way?

-Sean

Sean I'm not an expert on them, but I don't see how it really could as they are designed to fill up past the blockages. So if it was blocked I would think it'd fill all the way up! But stranger thinks have happened and maybe one of our more experienced members knows more about them than I do! FWIW!
  BK 

[Sean]

As I promised, I am posting an update here on our problems with low power, excess heat, and black smoke.

Today we visited W. W. Williams in North Las Vegas.  Unsurprisingly, they are now down to only two technicians qualified on two-stroke products.  We got Hank, who seems to really know his stuff.  While I was standing around, the maintenance supervisor for Clark County Fire came over to chat with me about the coach (he was there to pick up a fire apparatus), and had good things to say about Hank's familiarity with 8V92's (which were very popular in fire apparatus prior to Series 60).

Hank could find nothing wrong with our coach, except for a dirty radiator.  I have to confess to some embarrassment about not having noticed this myself (and no one here mentioned it either), and the price I paid for that gaff was to pay Williams over a C-note per hour to pressure-wash the radiator, which I could have done myself for free.  And, while that may have accounted for some of the temperature issues, I don't think it fully explains the low power or excessive smoke.

Hank also tried disabling injectors one by one to see if the smoke changed at all, but it did not.  Otherwise, his assessment was that the engine was mechanically sound.  He did not feel there could be a turbo problem with the boost readings we had, nor did he think it could be the bypass valve without other symptoms.

I did have them pull an oil sample for analysis, which should come back tomorrow or maybe Thursday.  That will, at least, tell me if I've sucked any dirt into the engine.

With no further diagnostics to run, they buttoned us back up and we escaped for less than $300.  I feel a little better about continuing to drive it in this condition, but I don't think we've solved the problem.  Before I spend any more money in the shop, though, I am going to try to burn through the last 170 gallons of this batch of fuel, and see if things improve after taking on a fresh load.  It's possible that the fuel I've got now has the wrong cetane number, or some other non-obvious deficiency.

I'll post more if I learn anything from the oil sample, or if we get any closer to solving this.

-Sean
http://ourodyssey.blogspot.com

[pete81eaglefanasty]

 Sean
I was wondering if the stuff they sell at Wal Mart called diesel kleen  could help you. it is suppose to increase the cetane up to 6. it also reduces exhaust emissions.

          Pete & Jean
            Fantasy

[Frank @ TX]

Hey Sean,
If you're going to Vagas, you may want to try a garage in Parumph (sp ).
It's something like Paulson.  I had some work done there a few years ago when I was passing thru and I thought they were great.
By the way the owner has converted a real nice Eagle.
He's a nice guy and is good with 2 strokes.
Hope this helps you
Frank

[TomC]

Make sure you're using the new ULSD.  I was in Las Vegas last Dec and filled with normal sulfur Diesel with my Mercedes-Benz.  Talk about smoke!  After a couple of tanks of ULSD, it was back to its' normal amount of smoking.  Good Luck, TomC

[H3Jim]

Tom, why would  the amount of sulphur affect the amount of smoke?

[TomC]

Good question-actually, I don't know why, but I know at least it was a smokey tank of fuel I got there in Las Vegas.  The car ran fine, just alot more black smoke.  Maybe it was industrial Diesel rather than on road.  Good Luck, TomC

[prevost82]

I don't know ... 8v92 should love lots of sulfur. When we were down in Mexico my 8v92 just loved it ... yes it smoke more on take off but at running speed it didn't smoke. Maybe Mercedes has issues with high sulfur
Ron

[Sean]

And the answer is (drum roll, please): The engine is dirted out, for the second time in less than 100,000 miles.

More detail is on our blog at this post:
http://ourodyssey.blogspot.com/2007/07/good-bad-and-ugly.html
(Read the sections labeled "The Bad" and "The Ugly").

The short story is that the oil sample came back, and it looks like we have dirt in the engine, as I was beginning to suspect.  Our oil consumption has gone up, and the low power/white smoke on start/black smoke on load is consistent with blow-by past the rings.

We'll need eight new cylinder kits, a turbo, rod bearings, and any number of miscellaneous parts.  I am guessing around $10,000 to get us back on the road.

We'll be going either to Stewart & Stevenson in Pueblo, if we can even make it that far, or back to Pedco, who in-framed our engine the last time it was dirted out.

I won't know until they start tearing into it where the problem occurred -- either something wore a hole in the intake, or the intake plumbing just came apart somehow.  If you are curious, I will be posting follow-ups on our blog (not here).

-Sean
http://ourodyssey.blogspot.com

[H3Jim]

Sean,

Bummer of an expense and it sounds like its not too good for your schedule either.

An idea for "next" time, and something I have been consdering myself is a by pass oil filter that will filter that kind of dirt out of the oil should your air filter or intake fail as yours must have.  Seems like some relatively cheap insurance.

Two years ago I had 125 ppm silicon  in my oil, but no other wear metals.  I change oil fairly often, but since I frequently go to the desert with bolwing sands, its not  diffiuclt for  sand to get in there.  I have been losing some power lately although I have also been adding weight.

[Sean]

Jim,

You can filter the dirt out of the oil, but if it is getting past the air filter, the damage to turbo, blowers, liners, and rings is already being done.  FWIW.

-Sean
(Who is on his third glass of Merlot, as a palliative.)
http://ourodyssey.blogspot.com

[JohnEd]

Sean,

Such very bad news.  Really, a bummer.

How could you have known that this was happening to your engine?  I agree that finding sand in your oil would indicate dirt getting in there but not neccessarily via the intake.  Oil analysis would have started a search even if it was a late one you would have been in the hunt maybe before terminal damage.  Is there a sampling device, like fly paper or somthing, that would retain any dirt getting past the filter and intake couplings for evaluation?

Didn't the mech say your blower and general mechanical condition was "good"?  How does that figure with blown rings and a worn blower? 

Is there no way to set up a 5 gallon gas can of good fuel and rig it into the engine fuel system for a short test run?  I did that with a gas powered rv to get it to a shop when the rust in the tanks overcame the fuel switching valve and the lines.  used an electric pump to get the gas to the carb.  It sat on the floor next to me and I am glad I didn't have a wreck and have a jerry can bouncing around.  The things I have done in the name of science.  Only save a few hundred dollars.

I hope you qare wrong about the overhaul and things come together for you in a cheaper fashion.

Best of luck

John

[niles500]

Sean - as I intimated at  BNO - I think you got screwed by someone - no way this could happen in such a short period with your documented usage - somebody screwed up here - Whatever you do and whoever you take it to DON'T let this happen again - make them test and "certify" ALL the entire intake system this time - there is NO WAY I would have anticipated this outcome from your detailed descriptioms of prior maintenance and repairs - It sounds like incompetent service - Just plain STUPID - What the heck did you pay for? FWIW

[Sean]

(Cross-posted:)

Well, Niles, the last folks to even touch the intake system (other than filter changes, which I do myself) was Pedco.  That was during the last in-frame.

When I talked with Pedco owner Virgil Cooley this evening to ask how this could have happened after his crew took pains to put it on correctly, he suggested that (1) something as simple as a braided hose might have fallen against the intake plumbing and abraded through it or (2) off-road driving (of which we have done some, but not much) might have worked a clamp loose, causing the intake to come apart.

The problem is that the whole intake system, other than the air cleaner housing, is buried in a very tight engine bay -- it's impossible to even see it without dismantling part of the bedroom and removing an access panel.  Until we get in there, we won't know how it came apart.

If I take the coach back to Pedco to have the new work done, I would hope that Virgil will step up to the plate to cover at least part of it, if it looks at all like the problem was related to workmanship issues on the last rebuild.  But, as you know, that can be very hard to determine.

If the intake hose is just loose, with the clamp dangling, is it because the mechanic that installed it didn't tighten the clamp properly, or is it because the air cleaner bounced around in its mount when I plowed through "the big puddle"?  It will likely be impossible to say.

In any case, it's a good bet that if I don't take it back to Pedco, there won't be any possibility for any credit, so that's one factor weighing in favor of going back there.  OTOH, if I felt certain that this was a screw-up on their part, then I would be foolish to want to go back there to have them do it again.

Anyone else here feel the same way Niles does?

-Sean
http://ourodyssey.blogspot.com

[H3Jim]

Although devastating and frustrating, I think after this amount of time and miles it falls more under an on going maintanence issue.  Or just the luck of the draw with the way its configured.  Pending more information when you get it apart.

If it happened within several or even 9 months, I might be pointing my finger more.

Pedco has such a great reputation, I would not hesitate to take it back.  I also suspect that if Virgil thinks he contributed in any way that he will cut you a deal.

I'd put that by pass filter on anyway.  I have to believe that the dirt cycling through over 1,000's of miles is much worse than if it got filtered out in the first 50.  You're right, the dirt would do some damage as it went through, but it still seems like its cheap insurance. ( said by a man that does not have one -yet)