I look after several Detroit 71 and 92 series diesel engines in stationary emergency stand-by service. They had been having injector problems which lead to fuel samples being taken. The samples were bad, which lead to discovering huge sediment (mud) buildups on the bottom of the fuel tanks. Engines are in heated indoor spaces and so are the fuel tanks. Is this just partials dropping out of the fuel over time? How much of it could be picked up from the engine fuel system and returned to the tank by the fuel return line? Has anyone ever heard of adding some sort of filter to the fuel return line? These engine do way more sitting than they do running, so the fuel does get old. Is diesel that dirty? Opinions and ideas welcome.
IMHO fuel tanks of engines that run infrequently are more at risk of accumulating sediment than tanks on equipment that gets refuelled every day. Keeping the tank full will reduce, but not totally eliminate, the accumaltion of water due to condensation. Most maintenance plans for standby gensets recommend that the tank be drained of any accumulated water and sediment on a weekly basis. The illustration below is from a Cat maintenance manual, but I can't see a DDA Manual recommendations being majorly different. You had the fuel that was in the tanks analyzed, but did anyone take samples of the fuel that is being put into them from the fuel supplier..? Also has anyone analyzed the fuel for the presence of algae..?
It sounds to me like what is needed is to do whatever it takes to remove the sediment, and then hire a fuel polishing service on a regular basis to ensure it does not happen any more.
No, we've never sampled the fuel from our suppliers truck, but I think I'll go do that just sh1ts & giggles. We're talking 30 years worth of accumulation here. Water levels in the fuel samples were very low, it was just the particulates that killed us. It was an amazing amount of mud, some of it magnetic, most of it not. We have our own fuel delivery truck, and I can see right to bottom of the tank with the help of a light, there's no sediment in the truck. But it's refilled 3 times a week as a average, so the fuel doesn't sit long enough to fall out. We never sampled fuel until it became an injector warranty issue. And unless there is a breakdown, we only touch these engines once a year. I'll have to approach the owners about stepping up their PM program. Fuel polishing is a good idea. Wouldn't be hard to set up a filter cart and run it through once in a while.
Making your own filter cart to suck the sediment out of the bottom of the tank shouldn't be hard. A couple of large-capacity 2-micron (or better) filter heads, some hoses and a pump, and away you go. My only other thought would be to suggest that you ask yourself is it easier to drop the sediment out of the hole in the bottom of the tank (I'm assuming they have one, and if not why not..?) or fabricate something to suck it out through the hole in the top..? The problem with sucking it out the top is that unless you get really creative with the suction end you only get what's directly below the filler neck, unless you do a complete vacuum drainage, flush, and refill after filtering. To equip yourself to do that is probably gonna cost a few $$, but either way I guess it would probably be cheaper than replacement injectors.
Out of curiosity , what are they finding wrong with the injectors ? Detroit Diesel will have primary & secondary fuel filters . Pretty good setup that will work under some nasty fuel conditions . If anything would think the primary filter would plug up & starve the engine of fuel . Had a similar issue with one of the cranes . I ended up draining the tank and power washed it out sticking the wand in through the filler cap and fuel sender port . Odd part was first symptom was an engine miss . http://www.heavytruckforums.com/showthread.php?51-Fwd-Trucks&p=3973&viewfull=1#post3973
Did about the same thing on a 40 year old truck and some Ag equipment. How did this stuff that looks like mud show up? I thank there maybe something to this new fuel. Here say is it can have 1 or 2 percent ethanol without out even being labeled. Just enough to break down contaminants from the refinery to your own tank. I do not know but I have never seen anything like this before the last couple of years.
The original problem was bad oil samples, fuel showing up in the oil. We changed injectors and the rebuilts started leaking too almost right away. I had the dealer send out a tech to have look and the first thing he wanted was a fuel sample. It went from there. The engines were running just fine. These engine all have normal "larger size" primary & secondary filters plus a Racor as a first line of defense. Our fuel may have been nasty, but I don't think it was dirty, at least not after running through three filters.
Sounds like you got it covered with the fuel filters . Did they leak bad enough to raise the oil level in the pan or notice a drop in oil pressure ?
As the young lady once said - "size isn't everything". Do you have any idea what micron rating are the elements..? Worst possible scenario is that you have something in there that will only trap particles the size of children, tree branches, & small dogs ..........
Oil level only increased slightly, but it was enough to make the samples go south in a big way. No noticeably drop in oil pressure.
Baldwin BF5800 & BF5810, not sure what the micron rating is on them. Racor was 10 micron, the dealer had us switch to 4 micron instead.
Having a tiny amount of 2 stroke Detroit experience, It sounds to me more like suspended water getting through the filters. And water is far worse than fine dirt in those unit injectors IMO. Saw the results of a 12V71 trying to digest water in the fuel that ended up with 2 torched pistons after the injectors started dribbling.
Something else to look close at is the fuel crossover lines & fittings in the head if you haven't already . A lot of places for fuel to leak internally .
Sounds like rust from condensation in the tank may be best to replace tank if you don't have good access to the inside for cleaning
In civilian life I've seen a lot more leaking cross over injector tubes than leaking injectors. If you put a leaking injector on a pop tester and hold pressure to just below pop off you will see fuel dribble from the tip if it is leaking. As far as mud in the tank I would suggest draining some of it into a clear glass jar and take a photo to show your supplier. The distributors and oil companies don't like bad press about what they supply and will likely work with you about what to do.
Can you get hold of better quality filters than Baldwin..? I'd class them on a par with Fram and Parts Store own-brand filters TBH. The spec sheet for the Baldwin filters does not include the micron rating which always gets me twitchy. So unless they are something super-special, which I doubt, they are nowhere near 4 microns. The Donaldson equivalents are P556915 (25 micron) for BF5800 and PF556916 (9 micron) for BF5810. Back to my earlier comment about removing nothing smaller than children, tree branches, and small dogs ...............
Not knowing the exact application for these engines I'm wondering if the fuel tank is too large for the application. Just thinking that maybe if a smaller tank was used the fuel would not be sitting for as long a time. Moisture from condensation can cause nasty stuff to grow in fuel and that along with rusting of the tank can cause many problems. And like someone above said a full tank will have less condensation. So if the tank is so big it will last a year or more that would not be a good thing. Then again if this is in a remote area where getting fuel delivered is a problem you just have to do what you can to keep it clean. I'd be contacting the fuel supplier for suggestions from them on special treatments like a biocide. Such as: https://powerservice.com/psp_product/bio-kleen-diesel-fuel-biocide/
Howe's Diesel Treatment also works very well with DD 2 strokes. Rick
Another random thought from a Detroit Diesel operator . I can understand sending an oil sample off and they found traces of diesel in the oil . These engines will weep a little fuel internal over time . It's the nature of the beast so to speak . Generally change the oil every 100 hours of use or if I notice a drop in oil pressure before hand . Detroit Diesel at 180 F temp showing 5 PSI oil pressure at idle indicates fuel in the oil . Time to change the oil & locate the problem given the time frame on the oil change . Only got one Detroit that don't leak fuel under the valve covers .
I've got a set of genuine GM filters on there now. I've always considered Baldwin to be the best of the aftermarket filters, but I agree that not finding a micron rating for their fuel filters is a little unsettling. I can access Donaldson.
This one is an emergency stand-by 1200 cfm air compressor. It starts automatically when the air header pressure drops. The unit was spec'd out to have enough fuel run for 48 hours at full load. Yes, the fuel tank is huge. It only runs about 1 hour a month for "test run". I can't imagine a harder life for a DD. No throttle either. Stop to full RPM to stop. To make things worse, it only turns 1550 rpm. It's been a ****-show from day 1.
FWIW I work on generators and they all go from dead stop to full 1800 RPM and I stopped worrying about it years ago. The engines don't care, they run some really long life cycles in this service. And 1550 RPM is no problem for a DD either, as long as it was built for the particular RPM. Thousands of them were made as generators that run 1200 RPM.
Agree Birken, We had several IR Drill rigs in the company with 8V-71's that were run that way. They were equipped with a hand lever on the governor that could be locked to keep RPMs low on start-up. But as these were often parked with them up on jacks near the face of the quarries I don't think any operators went to the effort of climbing up on the machines to lock the throttle as it would require them to climb down to start then back up to unlock and back down to operate drill. I don't think any of the failures of those engines were related to the start-up abuse, more from lack of proper maintenance of air filters or bad exhaust system maintenance letting water get down the stacks.
You guys don't have to sell me. I'm from an age when everything had a DD 2-stroke engine. I mean everything. The only thing the startup/shutdown hurts is the turbos. They are tough engines. I've only seem two that actually quit. A 353 on a pump that lost its lube oil, boiled its coolant out, seized, but lived to run again after it cooled down. The other was a 8V92T that lost cooling water flow, ran without cooling till it seized. The block was almost glowing when I got there. These emergency engines are all "run to destruction" no shut-downs on anything. I even like smell of the 2-stroke exhaust. It's almost sweet.
The used engine oil also has it's own Unique smell & texture about it . It's just different from other engines . Man it will sure soak in to the pores of your skin . Only thing I can attribute this to is traces of fuel in the oil . My take on the oil sample . It's normal to show traces of fuel in a two cycle Detroit after some hours on it . No need to worry unless oil level raises in the pan or oil pressure drops between oil changes . My gut tells me there's nothing wrong with the engine itself other then the nasty build up in the fuel tank .
The absolute nastiest stuff man has ever created is the oil trapped above the main cap bolts in any 2 stroke Detroit. And there is no way to get away from it when you spin them out.
I agree. I don't know of any still operating in my county. It has been a long time since I smelled that smell.
Aint that the truth RZ . No need changing clothing until done with that task . LOL !
I should can some used oil & ship it out your way .
Tyvek and nitrile gloves are a good start.
You made me remember an old guy who used to work for the dealer. He would diagnose a DD by tasting the oil. Yup, he'd actually taste it, not kidding. I agree with you about there being nothing wrong. But I'm having trouble selling that when the reliability engineers gets involved, and when we have two more 8V92T's and a 16V92T in the same area that aren't showing bad samples. I'll just keep dumping the oil when it tests bad. Fluck em. Another memory just drifted in.......that 353 I mentioned was inside a building and it had a straight pipe on it that ran though the roof and up above a pipe rack. About 20ft of 3" straight pipe. You could hear that thing a mile away. It was glorious.
I take that back, there is one 6V92 still around. Was with my fire department back when I was employed there, has since been sold to the next little VFD over as surplus. It had DDEC 2 and I had them put Jakes on it, was a nice ride. 400 HP fire apparatus rating. DDEC 2 would lug right down to 1400 RPM no problem. Full RPM 2100 IIRC. 3 mpg.
My first thought in the thread was … It's the year 2019 and sending an oil sample off on a two cycle Detroit . The people reading the oil sample don't understand the engine . They see a high reading on a chart and panic . LOL ! If ya aint careful you can spend more money on preventive maintenance then a full rebuild when the engine really needs it .
Surely no one would ever do that!
I'm thinking some of that "fragrance" is from the International Compound No.2 used to lube the bolts when they are installed.
I have tried to replenish my stock of IC#2, cannot find the original 'peanut butter' anywhere any more. As to DD Oil, once has been thru an engine ten minutes or ten hours or ten weeks you CANNOT scrub hard enough to remove the carbon that seeps into your skin if gets on you. Used Nytril gloves and Tyvek type overalls later in life but helped little as this crud will soak into and thru ANY product known to man then you have to wear it off as will NOT scrub off.
Yeah, I just use the Cat graphite based anti-seize now. (the stuff for head bolts and main bolts) IC#2 is hard to find.
Well doing a quick Google search I find at least one place that claims to have a couple cans for $79.88 each with free shipping. https://www.ebay.com/itm/DETROIT-DIESEL-COMPOUND-DDE-05198563-/142147233794
IC #2 also found in S60 service manual, is it completely orphaned even though they were still produced this decade?
Howe's Diesel Treat improves lubricity of ULS diesel fuel and helps keep the fuel algae free.