I have a dragline with a 4-71 DD it's new to me. But no past history, it's wet stacking bad. I went over some past posts and did some back ground checking and now I an looking for some direction. Ser# 4A 39878 4-71 RD 9 (serial # doesn't match what I have) injectors are HV7 Things I have done so for, changed oil to a straight 30 wt. plus oil and fuel filter. Valve lash is right on, injector timing right on. But the GM maintenance manual I have does't cover the governor that is on the engine to get me to checking the fuel injector rack. Crank case vent on the lower right bottom of the block is open are there more? Breather off the govenor is open. Some oil on the blower rotors. No broken or stuck rings, pistons and cylinders look good. I don't think it's blowing oil as much as it's blowing fuel. I can't get it hot, after an hour running and revving with the radiator covered up the best I can do is about 130* and the thermostat won't cycle.
A few more
Wet stacking? Maybe it's just the pic, but I don't see much oil leaking from the vent tube fitting. What makes you think it's blowing fuel? And how can you not get temp above 130 degrees? Are you sure your gauge is reading correctly? Looks like a fairly clean Detroit.
pull off the valve cover ad see if you can see control rods for the injtors see if all the racks are moving the same i will dig out my shop man tommow for you.
I think the spec was straight 40 weight oil. They were cold blooded even with a good thermostat with no load it was hard to see 150.
one of the cleaner 471's, have you checked the thermostat for opening temperature. If it in fact is running that cold you will get some degree of wet stacking. Any ideas on how many hours are on it? I'll get some more info for you tomorrow on checking the rack.
The engine iol has to low ash CF-2 compliant. Such as Rotela T strait weight or Delo 100. Delo 400 no longer has the correct certification. I believe the 4-71 is like my 6-71. In that there is a emergency shut down flap on the blower. It has to be reset at the blower! I tripped mine last fall and while it ran fine at a idle it had no power and blue out tons of black smoke.
Thanks for the replies Your right, hardly any oil out the vent, a little more out of the breather vent. Blowing fuel was a guess because the wet stacking seems thin, like diluted oil. As far as the temp, the guage is old, I was shooting the engine with a temp gun, and the thermostat never cycled and no coolant getting pushed into the top of the radiator. the right side of the motor is very clean it's the other side is the mess The control rod and injector racks seem ok. but the info from the manual would be great The GM book showed 30wt but everyone is recommending 40wt and I'll be going to that. Hope to check the the thermostat this weekend. About the hours, no idea. When I was looking in the inspection covers at the cylinders, it looked like it had been freshly honed. Emergency shut down is good and works, all I get is white-light grey smoke . I guess I am looking for more info on setting the govenor, thanks again for the help
Hmm, still not certain what your describing your wet stacking condition. Just to be sure we're on the same page, you can see three hex fittings just behind the oil filter can. The one nearest rear of block is a 90 degree flare fitting, that's what's called the "air box drain". There should be a short piece of tubing connected to that fitting to extend the drain to just below oil pan to keep drippings from getting on the block and oil pan. There will be a crankcase vent pipe as well, usually located at rear of engine, and will be about a 1" diameter pipe. Are you getting leakage from the air box drain or the crankcase vent? As for governor adjustments, are you having a governor problem? Unless someone has played monkey wrench with it, it shouldn't need any adjustments. Engine temp; when you were aiming a temp gun at it, were you checking the temp of the block? The engine block on a Detroit doesn't get terribly hot because there is air from the blower moving all through it feeding the cylinders. This also keeps the block cool. The only part that has coolant in it is the engine head. And Detroits used a low volume water pump. You should see some movement of coolant in the radiator neck when thermostat opens, but your not necessarily going to see a rush of coolant, maybe just movement of coolant. SAE 30 was the old Detroit oil spec. Detroit has since done some research and found SAE 40 gives better results. SAE 30 would be used in very cold climates. And as Cowboy Billy noted, it must be a CF-2 oil, and it should have a sulfated ash content of 1.0% or less. Delo 100 meets the spec the best, Delo 400 won't do, Texaco Ursa is good, Rotella is borderline as it's ash content is around 1.0%. It will work, just not the best for ash content. I'm wondering if you may have some failing injectors. You could simply remove the injectors and have them tested. Also, since you don't know the history of the engine, it's possible someone has been using multigrade 15W/40 in it, they will slobber when you use that oil. I would advise, now that you've changed it to SAE straight weight oil, is run it and run the dog snot out of it. Put a few hours on it, then change the oil to SAE 40. Keep us updated on how it works out, and be sure and post some pics of your dragline.
Dog snot? I have several -71s and a couple of -53s. Atco said everything I was going to, and I agree with him completely. But, I do run 15w-40 Rotella T in mine to prevent confusion w/ rest of fleet. The DD's do slobber if you let them idle to long or run fast w/ no load. You will never get temp. up without load. If mine slobber you can run them hard for a while (it does seem the longer they slobber the longer you have to work them) and they will clear up. Also, don't lug them, the work they are happiest with is running 3/4 throttle or better with a steady load. I would keep the dog away when he is sick. Once they are full of dog snot it takes working them hard and steady to clear them.:tong
In my case all my Detroit's slobber. I think you may have an oil er ring bad. You have the inspection covers off and would have seen that. Can you pull the exhaust manifold to see which cylinder it is coming from. It could be a stuck injector too. I know the n65's are pretty notorious for that.
Atco said: "SAE 30 was the old Detroit oil spec. Detroit has since done some research and found SAE 40 gives better results. SAE 30 would be used in very cold climates." I remember having the service bulletin from GM updating the oil spec to 40 weight. Of course doesn't mean I could ever find it.
4-71 Good info from everyone and I can only repeat some things These DD will run forever, I always have used 40W oil in these engines They dont like to idle long, they love to run wide open under a load I was thinking the thermostat was 165 degrees and as stated, it will run cold under no load. Did your thermo gun match up with what you were readying at the sending unit (good way to check the guage) I would work the crap out of it, for a few days and see what happens I dont think the governor has an issue, unless someone messed with it and even then it wouldnt cause wet stacking As stated I would pull the injectors and have them tested You really need to have someone re-install them that knows what they are doing and has the correct timing tool. Is this a 2 valve or 4 valve head, if its a 2 valve, it never will run real clean Looks like a pretty clean engine to me also Can you feel air coming out of the air box drain, you might have to run it hard to check this. An old trick if this air box drain is stopped up, is to pump about 20-30 pumps of a regular greas gun and grease in this hole. You can screw the end of a grease gun hose in the block, or screw a grease fitting in it. Pump the grease (good if the block is warm/hot) take out any fitting that maybe in the block and start the engine and run it real hard, the grease melts and cleans the crap out and just blows out. Good Luck and keep us posted
471 ATCO, help me a bit here, does this look like the correct governor cover on top? This is a shutoff lever and I was thinking the top just had a one shaft coming out of it, also what is this spring doing, thats hooked to it? It cant go in the forward direction, because it will hit the extra shaft and so if you pull the stop lever back to stop it, the spring doesnt do anything. Maybe the lever goes forward over the front shaft, but I always thought I had to pull back on it Do I see oil residue below the bellhousing? Wonder if the rear seal is leaking? These questions, has nothing to do with possible wet stacking, just wondered about these things
Hi Willis, that's a variable speed governor on that engine. I once operated an HT300 Link Belt with a 6-71 that had a governor just like that. It was ideal for operating a crane because it maintains engine rpm regardless of load changes. You could pull the throttle lever back to say 1500 rpm, and work the cranes functions, and the rpm would hold at 1500 because the variable speed governor throttled the engine. It was even kinda neat for driving the machine on the highway. Once you got in top gear and up to speed, just pull the throttle control on the dash panel. It acted like cruise control, holding rpm at a certain spot. Get on a little grade, and it would throttle the engine. Get to top of grade and flatten out, it would back off the throttle. That is the shutdown lever on top of the governor housing plate, it rotates CW to shut down engine. The spring is holding it in the engine run position.
My DD manual for 3-71 said 40 wt I have been running 15-40 because I didn't know any better till it was discussed here.
Here ya go fellas, plenty of good Detroit reading. Tejas Coach has been working with Detroit fleets for many moons and they've put some really good info on the interwebs. http://www.tejascoach.com/ddcoil.html
Thanks good read!:drinkup Guess I'll get some 40 wt at the DDD. Detroit Diesel Dealer may be the 40 wt will kill some of the smoke
I would ad that the inside of the blower looks normal and the outside of the engine also looks normal. A very typical 471. In my experience, every 71 series diesel ran best at full rpm under load. They did not like to idle at all. This includes the two cylinder models to the 16V's. Heavier oil will help some, having the HV7 injectors checked out and maybe exchanged or rebuilt would probably help a bit. It would also help if the coolant temp was raised to at least 165, maybe 180. That will tighten things up inside some and help control the oil leakage. Good Luck!
The more I read on that site and the links ( http://www.tejascoach.com/ddcoil.html ) the sicker I got about running 15/40 all the years in mine. It is a yard machine and not tons of hours but still make me :Banghead:Banghead
Yep, there's been a lot of research done on those engines, and Tejas has tons of experience with them in their fleets. These are old engines. A good many folks who happen to have one today just don't know the quirks these engines had. And they're so old, the info is not out there in the mainstream of engine maintainence. It's all tier III and regeneration now days. With the old Detroit; it was fuel, oil, and stand on it.
Thanks for all the info and help. Well the update, after talking to the local diesel shop while looking for an exhaust manifold, he asked me about the fuel. I was always under the impression that diesel lasted forever . So I drained the tank and got about 15 gals. of what looked like tranny fluid. Put 10 gal. new back in with some cetain boost /injector cleaner. The engine got hot in about 15 min. and to 180 in about 30 min. the air box drain is good and clean lots of air. Crankcase vent, nothing like you described, just the line off the govenor is that it? At the head,exhaust, radiator, hoses, oil cooler. No movement at the radiator, now I get a rush of coolant when the thermostat opens. The temp guage is off. Yep it had 15-40 in it, I put 30wt in and will go to 40wt I pulled the homemade elbow off the manifold and all the runners looked the same just a lot of carbon/ soot build up. I did'nt want to mess with the governer just check the settings, my gm book has the flow chart for tuning the engine and one of the steps to get to the rack adjustment is the governer. I want get it to the point of running the dog snot out of it before I pull the injectors Yep it's a 2 valve How should the governer be hooked up? the light spring isn't hooked up to anything so I have to kill it by hand. The front seal is is wet, I think you are right about the rear seal. Never looked in a DD blower before now I know Thanks again for all the help
ahh, now I see, look at that nasty exhaust pipe. :tong Got your temp up there now, fresh fuel, some SAE 40...start her up and run her like your mad at it. BTW, nice looking old crane :yup
71-series... Great engines. The Detroit 2-stroke temp gauge measures the temperature of the coolant just after it comes past the thermostat. The perferred temp gauge uses a capilary tube with a sensing bulb. These bulbs come in various lengths. Get the correct length so that the tip of the bulb extends slightly into the coolant stream. Having a stationary engine in your dragline means you can mount the gauge where convenient and observe it at your leisure. (Most of my experience is with 6-71 powered on-highway coaches from the 1950s). We had a cap-tube temp gauge in the engine compartment to use to calibrate the electric gauge that was forward on the dash. Unlike 4-strokes, the 2-stroke Detroits can't tolerate temps of much over 200 degrees. Even with a 15 pound cap on the radiator, the head(s) are prone to cracking above this relatively low temperature. Remember, these engines were designed in the 1930s. The alarm stat/shut-down system is always stamped to activate at 203 degrees or 204 degrees or 205 degrees. This is the sequence of operation of the engine's temperature control equipment as things warm up: Thermostat opens. Shutters open. Fan clutch engauges. Every engine has a thermostat, the other two (extra cost options) were specified only if the original purchaser was more concerned about fuel economy and life cycle costs than about initial purchase cost. There are two common thermostats: Nominal 170 degrees and Nominal 180 degrees. Each starts to open at its rating and is fully open by 15 degrees warmer. The 170 (fully open by about 185) is used when there are shutters (the shutter stat opens the radiator shutters somewhere between 185 and 190), and a clutched fan (the fan clutch stat is set to activate between 190 and 195). The 180 (fully open by approximately 195) is used when there is no additional temperature control equipment. In both cases, all the cooling equipment (if properly functioning) is fully functional by 195. Wet stacking occurs only when both the incorrect oil AND long periods of idling are perpertrated upon the poor engine. Run the correct oil, minimize idling, and you won't have any problems with wet stacking. Wet stacking is marked by oil seemingly POURING out of every pore of the engine and exhaust system. Some excess smoke comes out the exhaust, but not much compared with what is STREAMING out of the lowest clamped joint in the exhaust pipe. We used to tell the drivers, "Don't idle the engine any longer than a traffic signal," and "upon start-up, just build air and go." The instruction, 'run the engine hard for an hour' is necessary only to clear things up after changing the oil and changing the operating parameter. I'd be a little concerned about the oil on the blower lobes as indicated in your photo. Every blower horn I've pulled off has exposed lobes that were clean as a whistle. The concern is that when sufficient oil leaks into the air intake, the engine can run on its own (the mechanic runs away, the engine over-speeds to self-destruction). The Detroit Diesel book indicates that you need two special (matched) pullers to disassemble the blower. One turns left, and one turns right. When I was working on these engines, we sent the blowers out for rebuild, but I've been told that one can pull the drive gears off the ends of the lobe shafts with two pullers that turn the same direction, it just takes some finesse. (I've had a Detroit 8V71 run away on me when I was driving a 10-wheeler dump truck. It was in gear and loaded to gross. The engine noise changed. That was all. It was always under control. Later that day when we were messing with it trying to diagnose, it took off again. THANK GOD my associate (the truck's owner) was standing there at ready with a wire tied to the shut-off lever on the governor. Valves were floating in the 3/4 second or so that it took him to realize it was time to pull that wire. It turned out that there was a rough spot on the control tube of the rack (spring-loaded fingers...supposed to prevent this sort of thing). I.e., it was fuel control under the valve cover -related. My concern with your engine is that it appears to be 'oil in the intake' -related and pulling the fuel cut-off lever won't help. Make sure your emergency shut-down (cuts air) works. It would be a real shame to lose that engine....or worse, injure yourself or someone else. Don't freak out over this, but they don't call it 'run away' for nothing. Good lookin' crane, man. Hang in there with it. ~0le
Thanks again for the info and help. The emergency shut down works You would think for as many 4-71s out there, it would be pretty easy to find an exhaust manifold :beatsme
471 I have a exhaust manifold, I bought to go on a 4-71 in a Drott I was working on and the man never paid me, so I didnt install it. I dont know about the freight, but I paid $100 for it and thats what I want for it plus the freight. I will package it up free. If you want it PM me and let me know