DDA Silver 6V92 TA DDEC

Topic: DDA Silver 6V92 TA DDEC (Read 2603 times) previous topic - next topic

DDA Silver 6V92 TA DDEC

November 25, 2017, 04:20:02 pm

In re: "It Broke 5 Hours Into Ownership"

While awaiting the completion of my coach bulkhead repair, I was reading through the various threads and encountered this one, about the failure of a newly-acquired '93 6V92 equipped U300 out in the wheat fields of eastern WA. The narrative description of this failure was nightmareish, and of course it started me thinking about my own DD 6V92TA DDEC equipped U300. Two things cause me to work up a case of high anxiety about my engine:

1. My bulkhead problem has caused me to lose all faith in the purported diligence of the PO in terms of coach upkeep, and;
2. The PO was running Delo 400 (15w-40w) which is not the correct oil for the 2-stroke 6V92.

In light of these issues, I have a low level of confidence that the PO operated the coach properly, particularly with regard to the potential for the engine to overheat.

Consequently, my reaction to the experience of Mr. Airplanes, with his heart-rendering breakdown on the road, is to have a thorough oil analysis and perhaps a technical evaluation done on the engine at a Detroit shop. My questions to the membership are, 1. Would oil analysis (of the drained Delo 400) reveal anything at this point about the engine condition, or whether the engine had been overheated, and 2.Would a competent Detroit shop (we have several here in Spokane, which is a major trucking center along I-90) be able to conduct any test(s) that would reveal engine condition at this point. The coach and engine have 86K original miles, but that wouldn't matter if the previous operator had consistently operated the engine improperly.

Any information, suggestions or insights will, as always, be greatly appreciated.

Re: DDA Silver 6V92 TA DDEC

Reply #1 – November 25, 2017, 04:46:33 pm

Oil sampling, and a compression test might give you some insight. The oil issue on the 2 strokes is cylinder liner ware. To check for that some tear down is required. The failure on Mr Airplanes was trash or a berring failure on the blower. Others may chime in but the berrings don't care what oil as long as they get some.

As far as the bulkhead there those of us that have problems and those that will. The bulkhead issue is one of those things that is kind of like putting a roof on your house.

Re: DDA Silver 6V92 TA DDEC

Reply #2 – November 25, 2017, 04:48:40 pm

you might want to PM Pierce here from the forum and try to connect with him for a live discourse on the topic.

Tim Fiedler

Sure Start Soft Start

TCER Direct generator-gas-prod 630 240-9139
Gen-Pro

Re: DDA Silver 6V92 TA DDEC

Reply #3 – November 25, 2017, 04:54:19 pm

Thank you, this is reassuring, and I think I will have oil analysis and the compression check done as soon as the coach is out of the bulkhead repair.

Because it is getting the bulkhead and tubing structure replaced, Inhave ceased to panic and obsess over the bulkhead condition and repair, and instead obsess over the myriad other things that could be lurking in a 28-year old coach with now questionable maintenace history.

Re: DDA Silver 6V92 TA DDEC

Reply #4 – November 25, 2017, 04:54:59 pm

I'll do that, thanks!

Re: DDA Silver 6V92 TA DDEC

Reply #5 – November 25, 2017, 05:27:21 pm

Before considering ANY shop to evaluate your engine, VERIFY that they do have a tech old enough to have grown up on the 2 stroke DD engines.

Having a "new guy" evaluate your engine is useless.

Re: DDA Silver 6V92 TA DDEC

Reply #6 – November 25, 2017, 05:53:29 pm

Quote from: wolfe10 – November 25, 2017, 05:27:21 pm

Before considering ANY shop to evaluate your engine, VERIFY that they do have a tech old enough to have grown up on the 2 stroke DD engines.

Having a "new guy" evaluate your engine is useless.

Hit the nail on the head. Knowledge without wisdom and experience is not worth much.

Re: DDA Silver 6V92 TA DDEC

Reply #7 – November 25, 2017, 06:09:08 pm

I agree Bret, and will do.

We're fortunate here to have a few experienced DD techs because this was a trucking and commercial (bus) transportation hub, as well as an Ag, Forest Products and Mining center, so Detroits abounded.

No one will touch mine unless they can bonify their verifieds.

Re: DDA Silver 6V92 TA DDEC

Reply #8 – November 25, 2017, 06:16:36 pm

You have a coach with 89k on it and it has the wrong grade oil for the application. That does not mean the engine is damaged. Using the higher ash oils contributes to premature wear in the cylinders and main bearings over time. At some point when the coach was new there were way more 2 strokes running the roads,oil service places had it in stock. Over time coach builders went to 4 stroke diesels and over more time the shops quit carrying 2 stroke oil for these engines, They could get it but didn't stock it because of demand. In a commercial application IF you can get 500k out of the engine before needing a rebuild running 40wt , Lets use that for our magic number. If the improper oil was used over a long time you might only get 450k out before needing a rebuild. In a fleet environment that adds up to lost life and revenue. In a RV environment it is somewhat different. Realistically how many miles do you think you will drive your coach per year? How many years would you think it would take to reach a 450k mile rebuild point? Have a oil analyst done on your oil in there now,Change it using the recommended low ash oil DELO 100 is what I use. Go forward and change it once a year or every 8 to 10k miles. There are way more important things to be worrying about that if my cylinder liners have wear and I will not get that extra 50k of life out of my engine. Worry about things like is my Liquor cabinet stocked fully for my Foretravel friends and do I have enough steaks,etc,Things like that.

Re: DDA Silver 6V92 TA DDEC

Reply #9 – November 25, 2017, 06:20:15 pm

1. Oil analysis on the Deli 400 would probably tell you something but I doubt it would be all that useful.
2. Without getting into the engine there is not much a DD shop will be able to tell you. One thing they can do is hook up a Pro-Link Diagnostic Scan Tool to see what the DDEC says. Hum not sure if your 89' has a DDEC...

My advise (worth what you pay for it) is not to be in too big of a hurry to just start fixing things until you know what you got. Change the oil, drive a 1000 miles, draw an oil sample, and send it in. You'll have a much better idea of the engine after you see those results.

The 6v92 is a strong tough engine. Used in lots of fire trucks where they run em' at WOT for hours on end. They can take it. Just don't overheat it. Being a 2 stroke it fires every stroke. This is great for power but does cause it to build up more heat in harsh conditions. Read that as "mountain passes". Look into installing supplemental water cooling system for your radiator. Lots of people running 6v92's have done it. Easy cheap and effective.

I'm pretty sure mine had 10/40 in it when I bought it. It's coming up on 200,000 miles. Still running strong. You can't control what happened before you bought it but you sure can from here on out.

see ya
ken

Re: DDA Silver 6V92 TA DDEC

Reply #10 – November 25, 2017, 08:38:27 pm

My 6V92 was running on 15W40 Rotella when I bought it from the PO. I changed to the proper oil and I've driven it 50,000 miles all around the country since then. The oil analysis shows everything normal. Follow the manufacturer's instructions from now on and don't worry. The stuff you worry about never happens anyway. It's the stuff you never thought of that suddenly jumps up to bite you in the butt!

Re: DDA Silver 6V92 TA DDEC

Reply #11 – November 25, 2017, 09:41:24 pm

Randall is your coach side or rear radiator?

Re: DDA Silver 6V92 TA DDEC

Reply #12 – November 26, 2017, 08:22:21 am

Quote from: Tim Fiedler – November 25, 2017, 09:41:24 pm

Randall is your coach side or rear radiator?

89 would be rear.

Re: DDA Silver 6V92 TA DDEC

Reply #13 – November 26, 2017, 08:50:51 am

I agree that Pierce Stewart here on the forum is the most knowledgeable of the DD from our ranks so I hope he responds. But I think if your engine had been overheated you would know if there had been any damage. Warped heads would be the consequences of over heating. The most I would do is have something called an "Overhead" done on the engine. This is primarily a valve adjustment but a mechanic with the proper Detroit software can tell lots of things about your engine and they can run a compression check at the same time. Cost for an Overhead and electronic analysis should be under $500 and its a good way to start off you travels with a high level of confidence. 6V92's are still used extensively for generators, pumps and boats so there are still shops that know how to service them. It's hard to find truck shops that have the software a two stroke DD mechanic so contact Detroit for the local off road distributor.

Regarding oil analysis, it might help give you some confidence but don't rely too heavily on their conclusions. I had my oil analyzed for several years and it came back showing contaminant levels several times. I had a partial tear down in 2015 and with 160,000 on it the engine showed no appreciable wear so the oil analysis was a waste of money in my mind. The 6V92 is a very durable and reliable engine I love mine so relax and enjoy yours.

In an absolute worst case scenario, the 6V92 is the least expensive diesel to overhaul, about 50% the cost of a Cummins or Cat.

Re: DDA Silver 6V92 TA DDEC

Reply #14 – November 26, 2017, 11:48:31 am

If rear, is the fan in this coach subject to the fiberglass vs nylon fan blade concern that Scott Cook endured?

Re: DDA Silver 6V92 TA DDEC

Reply #15 – November 26, 2017, 01:14:50 pm

Quote from: Tim Fiedler – November 26, 2017, 11:48:31 am

If rear, is the fan in this coach subject to the fiberglass vs nylon fan blade concern that Scott Cook endured?

Yes

Re: DDA Silver 6V92 TA DDEC

Reply #16 – November 26, 2017, 01:32:17 pm

The Detroit 6V-92TA is about the most reliable diesel engine with the exception of the straight six DD 6-71 series. Mercedes still produces new 6V-92TAs for use by the military and countries around the world where the smog laws are less stringent. Detroit has manufactured about 3.5 million of them so is the reason Kent makes the point for 50% cost of overhaul compared to Cummins and even less compared to some CATs. The 150 degree lower exhaust temperature means no dropped valves on these engines.

I still am having trouble with the blower failure five hours after purchase. This is the blower/supercharger found mounted on the top of dragster engines at every drag strip in the world. Long periods of storage should not be harmful to the blower and running out of oil would take out the rest of the engine along with the blower.

I have been contacted by a couple of Detroit owners that had purchased coaches with modified air intake systems. One coach had the entire induction system removed and replaced by a small K&N filter mounted in the engine compartment. His complaint was black smoke out the exhaust pipe while driving.

The only possible thing I can think about happened to me this last week. On a long trip, our S320 suddenly dropped a cylinder and several minutes later, another cylinder. Pulling to the side of the road, I turned the engine off and looked under the hood. Nothing amiss here. Starting the car, the problem was instantly gone. This happened about every 400 miles. I went online and found others with the same problem. It seemed related to the MAP (mass airflow sensor) so I ordered another ($23.00 delivered) and while I was installing it, I checked the air cleaner. It looked great on the engine side but when I took it out, I discovered a rat had taken up residence in the air filter box, stuffing it full of Fiberglas from who knows where. So, to make a long story short, there is a possibility that during a long storage period, rodents worked on the air cleaner and somehow ate through the wire screen (if it had one) and allowed the paper to be ingested by the blower.

Using Delo 400 15-40 is not the best idea because of increased wear from piston scuffing and camshaft wear because of the high pressure needed to operate each cylinder's unit fuel injector/pump. After extended high engine loading like a fire truck running the pump at a major fire, the oil is very thin and idle oil pressure is as low as 5 psi. The oil thrown off is then not sufficient to lubricate the cylinder walls and cool the piston crown. This is why a fast idle feature is included in buses and fire trucks. With the light duty nature of the engine's use in RVs, this increased wear is much less of a factor. The small air box covers can be removed to allow limited inspection of the pistons and rings for scoring/ring breakage.

Here is a good PDF with almost everything you need to know about your engine: https://avtec.edu/sites/default/files/DDC%2092.pdf

We also bought our coach from an owner who had no maintenance records and in taking to his wife, said the coach had not seen much in the way of oil changes, etc. The engine had it's hydraulic pump belt fail and had gone through several fault codes that I later brought up. That was at 60,000 miles. At over 100,000 miles, the engine runs great and in a 6K mile cross country trip last year, it used 2.5 quarts of Delo 100 for the entire trip.

OK, your 6V-92TA as fitted to your coach. With the rear radiator, you don't have to worry about the hydraulic pump, just making sure you have updated fan installed so it does not fly apart as some have done. You will have trouble starting in cold weather as Detroit had no glow plugs or heated intake screen. The turbo versions have lower compression ratios so don't light off like the non-turbos on the first revolution of the crankshaft. This means you need a block heater installed in the proper location as Detroit intended, low down on the engine block, not the external thermostat location that Foretravel installed it in. In Bishop, CA, I ran a IR gun test on the different engine components after being plugged in and the block heater on all night. The crossover pipe was hot but not much heat had reached the engine block.

Starting your Detroit: in cold or even cool weather, you will notice that after cranking for a few seconds, one cylinder will fire, followed by another and then another until all cylinders are firing. This will include while smoke out the exhaust pipe either in small amounts in cool weather or prodigious amounts in cold weather. This will kill all insects within a couple hundred feet as well as bringing out all the tent campers with stones in their hands. This is pretty normal and does not indicate anything wrong with the engine. With the block heater installed in the correct location, an hour or two should bring the engine to like almost instantly.

One good idea is to purchase a Pro-Link 9000 reader with a Detroit DDEC slide in cartridge off ebay or Craigslist. This will test a million items (actually about 45) with little operator skill. I purchased two at about $100/each and notice that one sold for $46 delivered on ebay a couple of months ago. You can retrieve fault codes, test injectors, read real time MPG or overall MPG over the entire life of the coach including the gallons of diesel it has consumed. Since you don't have the hydraulic cooling system with it's set of problems, you will have one less system to contend with. The DDEC WILL NOT allow the engine to overheat and damage itself unless an operator uses the "override" switch. So, unless the PO somehow overheated the engine and then used the override, you probably don't have any heating damage. Just to be safe, I don't let the temp go much above 200 degrees and gear down and/or slow down to keep it cool. If in doubt, retrieve the stored DDEC codes and see when and what length of time they occured.

Contrary to common belief, when Detroit went to the DDEC (electronic controls) there is no longer a RACK TO RUN. That's right, no rack to run so with a little mechanical knowledge and mostly hand tools, the entire engine can be easily overhauled. Just read the manuals and watch YouTube videos. The complicated injector adjustments and timing are a THING OF THE PAST and do NOT apply to any 2 stroke installed in our Foretravels.

So, you have an electronic engine with almost bullet proof engine mounted ECU with heavy duty wiring to the injectors, a lift pump that is heavy duty, etc, etc. Just change oil, focus on engine compartment insulation, fridge compartment insulation and all the other little items all coaches need. Then drive it and have fun.

Out of the total Foretravel owners, not that many will read the forum and be up to speed on bulkhead issues or oil requirements. This is what you read this forum for. To educate yourself and be able to fix current problems and avoid others down the road. If this were an aircraft, there would be constant technical papers issued to deal with every issue. Unfortunately, it's not.

Pierce

Re: DDA Silver 6V92 TA DDEC

Reply #17 – November 26, 2017, 01:38:43 pm

Randall

Not sure if you have fiberglass fan, worth checking.

Here is a thread of interest:

Fiberglass radiator fan explosion!

Here is the most important info, fan available (as of a year ago) and under $200

Quote from: RRadio - 5 years ago

Quote

The fiberglass fan on my 1991 U300 with 6V92TA engine and less than 80,000 miles on it lost a blade while cruising on interstate 40 at a steady 1500 rpm. The blade hit the front core of the radiator and a small hose that I haven’t yet identified. The engine was vibrating badly and I pulled over thinking I had a flat tire. Road service sent out Tennessee Towing and they took me to J&K Truck Repair in Crossville TN who refused to do the repair even if I showed him the cash beforehand. He had at least one garage bay empty all day and as many as three mechanics mopping the floor at once. He wouldn’t even allow me to stay in his parking lot where the tow truck left me. He called Reed Truck repair and they sent a mechanic to look at it, but they also refused to fix it. They called everyone in town but didn’t find anyone. I walked across the street to the BP truck stop and asked if I could park in their truck parking area but they wouldn’t allow it. I then walked over to Cumberland Worship Center and asked if I could park in the church parking lot and they said I could. I found the broken blade and removed all of it, putting all the pieces together to be sure none of it was still in there. I removed the water sensor from the top of the radiator and put it in a bucket of water on the back bumper so the computer would allow the engine to run. I started the generator and let the air compressor pump up the air brakes and suspension. I then started the engine and immediately limped away slowly to the church parking lot without letting the engine warm up. Now I’m in the process of removing the radiator myself in the church parking lot 30 feet away from J&K Truck Repair. I worked on it until it got dark last night and then walked over to a pizza joint cuz I was starving. The lady who owns the place asked me what’s wrong so I told her the story. Her son in law owns a trucking company in town and she said she’d call him. I’m telling everyone about J&K Truck Repair, Reed Truck Repair, and the BP truck stop refusing to help me at all. Tennessee Towing was very helpful however, as was the church. Without them I don’t know what I’d do. I’ve never felt so alone before. What a cold hearted little town to be stranded in. I called Foretravel and got some valuable advice. They told me to remove the radiator from the bottom of the coach because there are brackets that won’t fit through the rear door. I see the brackets that they’re talking about but I really think it will fit through the rear door. Have any of you removed the radiator through the rear door successfully?... Those of you with a fiberglass fan should get rid of it before it explodes. According to Foretravel it has been replaced by Flex-O-Lite part number 8681 and it’s now a plastic 28” diameter fan blade which hopefully is stronger? The radiator is unavailable and VERY expensive. I’m told I’ll have to get a local radiator shop to order a new core and solder it in which will take a week or more and cost a thousand dollars... (sigh)... thought you guys would wanna know this stuff.

Scott

Re: DDA Silver 6V92 TA DDEC

Reply #18 – November 27, 2017, 10:08:44 pm

That sounds like good advice. I didn't realize we were talking about such a miniscule difference. I'll be lucky to put on 5-10k mi. per year. At 62, at that rate, It's doubtful I'll get to 450,000 mi.

Thanks!

Re: DDA Silver 6V92 TA DDEC

Reply #19 – November 27, 2017, 10:11:17 pm

Rear.

Re: DDA Silver 6V92 TA DDEC

Reply #20 – November 27, 2017, 10:13:46 pm

I know nothing of the fan issue.

Re: DDA Silver 6V92 TA DDEC

Reply #21 – November 27, 2017, 10:55:12 pm

Thanks very much to Pierce for this very thorough and valuable information pertaining to the DD6V92. I will read again in depth and apply to my situation.

Re: DDA Silver 6V92 TA DDEC

Reply #22 – November 27, 2017, 10:58:23 pm

Thanks to Tim Fiedler in re the Fiberglas fan issue, about which I was totally unaware. As my coach us in the shop now, this will be an opportune time to check to ensure that the Flex-a-Lite fan has been installed or install it if it hasn't. I view this as a bullet dodged, as I would certainly not want to experience tge disaster that RRadio had while on the road.

Re: DDA Silver 6V92 TA DDEC

Reply #23 – November 27, 2017, 11:25:36 pm

Most diesel engines are extremely tough, after all, Many will run 600 to 700 miles a day for 2 or 3 weeks without service. They are designed that way with huge oil pans Etc. Your engine is also used in Marine applications where a breakdown is more than a minor inconvenience and can operate for 24/7 for a week at a time or more. When I was younger I worked in a rock quarry where are the two stroke Detroit diesels ran 10 to 12 hours a day at full blast, 6 days a week for 10 months, and untll winter came and they were pulled back into the shop. That being said, I would not recommend that maintenance schedule in your best interest. That's pretty tough Duty. Hope you sleep better

Re: DDA Silver 6V92 TA DDEC

Reply #24 – November 28, 2017, 06:19:16 am

Had alot of the older 2 strokes on the platforms as fire pump engines,they never idled,would go right to full rpm usually 1800.

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