I've had this Hitachi EX270 LC for a few years. It has a Hino engine hooked to two Kawasaki hydraulic pumps. The automatic speed control modes never have worked on it since I bought it. So I control the speed with the hand throttle. The machine does not have a tachometer and I do not want to overrev the engine or pumps. I know the engine should have a governor, but without a tach, it's hard to say at what RPM the engine is governed at. Usually, I run the engine on the slow side, but well above lugging it. But in heavier digging it works a lot better and faster at higher RPMs. Does it hurt an excavator to run it below full throttle, or even at half throttle? How about at full throttle? Is that harder on the engine, pumps, and other parts? Opinions and experiences appreciated!!
Provided that the throttle lever is calibrated right, running it at full power shouldn't hurt the machine but it increases fuel consumption significantly. For general digging, I find running at around 4/5 of the max RPM provides the best balance of productivity and fuel efficiency. For grading, I find 1/2 throttle works best. I avoid running any slower than that because boom lift becomes too slow when doing combined functions. In special situations (such as in pond digging), I crank it up to full throttle because pond bottom moss is impossibly tough to tear. Another reason to avoid running the engine too slow (1/3 throttle or below) is that the engine will have to put in more fuel per stroke to get the same amount of work done than at a higher RPM. The engine runs cleaner when working at 1/2 throttle or above. Running the engine at full throttle does accelerate wear on the engine a bit, so I generally only do it when it's necessary. Short answer is that the best speed to run at for grading is half throttle and the best speed for most digging is 4/5 throttle. At least that's what I find works best on the machines I've run. But I know a lot of guys who just crank it to max throttle all the time without thinking, even grading. I think that's unnecessary and wasteful on modern machines, wasting fuel and wearing out the engine.
on a doosan...on standard mode, the rpm is at 85%..on power mode 100%!! but prefer by far the standard mode...so i guess all the other brand are the same....
I have always run wide open 100 percent of the time.
And I have NEVER seen an operator that didnt.:drinkup
I would get the throttle fixed, IM not a Hitachi expert but hydraulics for excavators are very intelligent and your throttle dial not only controls the engine rpm but also the powershift pressure. Your engine and hydraulic pumps are tied togethor through the dial. If you turn down the dial you not only decrease engine rpm but also the maximum swashplate angle of your pumps. Running a manual throttle cable will not allow the ecm to upstroke and down stroke the pumps efficently as the machine comes under different loads and pressures, which will cause the machine hydraulics and engine to be over worked and burn excessive fuel and make excessive emmisions.
i always place my throttle position in R&R mode...for "rock and roll". there are not many udders on my jobsites to milk...i need to get stuff done.
Cant make puppies LOL
X 100 i want all the power right when i need it, not when it thinks i need it!
The only time I perform any operation at less than full throttle, is loading or un-loading on the lowboy. I do that at somewhere between idle and half throttle, just for the simple reason that you don't want one track to take of before the other one in that situation. We haul the PC300 on a folding neck lowboy with outriggers, but 99 percent of the time I haul the PC200-2 on a rigid neck tandem lowboy with a dovetail. Trailer is 8' wide, and center of rails of the 200 are just a shade under 8'. So you don't have much room for error. I will say my Komatsu machines are VERY smooth loading, as are Hitachi machines that we've rented. I hate moving Hyundai hoes, I've never ran one that the tracks were smooth at any engine speed. We rented a 320 Hyundai with a hammer on it a few times, granted it was an older machine, but that was the biggest pile of junk I think I ever ran. You had to have it full throttle, as it wouldn't climb on the trailer any other way, and when you hit the travel pedals, one track was guaranteed to take off before the other one... But you never knew which one would do it.
Playing around with a 325 CL in a landfill site about a month ago when the local CAT onsite mechanic rocked up to fix a engine management problem. During the conversation on how to alter different settings via the in cab interface he said that the local CAT dealer pre-sets all excavators they supply at 85% power output as that is deemed as enough for the majority of tasks performed. Needless to say that I now alter the output myself to match the task.
Getting that fixed might be nice. Does anyone have any advice on what to look for or how to go about this? At the present time, it's basically a manually controlled machine, which works OK. Operation of the different power modes obviously involve the machine's computer system, so it may be cost prohibitive to fix? Or not? I may also get a laser tach and check the engine RPM. Without doing that, I wouldn't run it at full throttle for fear of overreving the engine and pumps. The old girl runs great and is remarkably trouble free, but I don't want too push her too hard.
For the guys who always run at full throttle, here are some production and fuel consumption numbers from my actual experiments. Machine: John Deere 200LC 80% throttle on dial, Economy Mode (i.e. 75% of rated machine power): 270 cu. yds./hour stripping and stockpiling topsoil 240 cu. yds./hour digging in sand 90 cu. yds./hour pond digging 15L/hour average fuel consumption 100% throttle on dial, Economy Mode (i.e. 94% of rated power): 290 cu. yds./hour stripping and stockpiling topsoil 250 cu. yds./hour digging in sand 130 cu. yds./hour pond digging 18L/hour fuel consumption 100% throttle on dial, H/P Mode (110% of rated power, computer automatically revs engine beyond max when it detects extra power needed): 300 cu. yds./hour stripping and piling topsoil 270 cu. yds./hour digging in sand 210 cu. yds./hour pond digging 21L/hour fuel for topsoil and sand 23L/hour pond digging So you see, for lighter work, running at 80% throttle gives you almost the same production for quite a bit less fuel. But for other tasks (such as pond digging for me), nothing short of max power could cut it. When I tried to dig pond at less than max power, the arm crowd slowed to a crawl, and I couldn't fill the bucket. But in H/P mode, for whatever reason, the arm crowd became 3x faster, and I was able to fill the bucket, hence the far better production at max power. Swampdog, I don't know what the computer issue is on your machine, but the ECU often costs upwards of $2000 from the dealer. Try to fix it if you can. If not, at least try to check the RPMs using an adjustable strobe lamp and making a white marking on the belt. In the interim, listen to the engine sound of a properly set up excavator at full power, and set your throttle to sound a tiny bit below that. P.S. The JD 200LC is a real dirt hog. Mine has a just rebuilt engine, new pumps, new swing motor, new track motors, so it runs like a brand new unit. It digs way faster than any CAT 320 and most other machines in its class. My 10 year old machine will probably even outdig a brand new 320D. P.P.S. The Hitachi EX200-5 burns less fuel with its Isuzu engine, but is significantly slower than a Deere 200LC.
Sultan, thanks for the detailed response. Interesting and helpful information! This Hitachi 270 has good power, even at partial throttle. It pulled about 20,000 yards of heavy blue clay out of a pond and had no problem digging that using a two yard clean up bucket. I rarely use the smaller bucket with teeth, since the machine handles the large bucket well. I should get a tach such as the type you suggest or a laser tach. It also occurred to me that an easy way to get a rough idea of the engine RPM might be to time the swing time for the machine. This machine is supposed to do a full 360 degree turn in about 6 seconds at full throttle. At the speed I usually run it at, it takes a little longer than that.
You can mount a universal electronic tach like an IssPro (I think that's spelled right) which will use a number of different triggering methods and can probably find some sensor type that will work. This would be independent of the computer systems so there is no chance of messing up something. I put one on a truck diesel and used their sensor that plugged into the stock tack hole on the engine. As I recall it will work with a sensor placed next to the flywheel teeth and a lot of other methods, even will use the alternator output as a last resort.
Because your computer isn't working, your pump has become a fixed displacement pump that always runs at 70% of max flow. Thus, the behaviour of your machine will be very different compared to mine. Just a bunch of points: -Because of the pump running at 70% of max flow, the swing speed would be slower. If a 360 degree swing was supposed to take 6 seconds with a computer, it would now take about 8.5 seconds without the computer. -The advantage of having a working computer is that you would have faster cycle times and lower fuel consumption in lighter digging -Another advantage of having a working computer would be that you would burn much less fuel doing jobs like stump pulling, where you need high pressure and low flow. Without a computer, the pump would be wasting energy pumping a high volume through the relief valves. -Computers are not as great as they say they are. In heavy digging like pond work, you're better off WITHOUT a working computer. -On my excavator, the arm crowd was very slow in economy mode because the computer was reducing the swashplate angle of the pump in my excavator. This caused the pump to pump very little and the machine to dig very slowly, -When the computer doesn't work, the pump holds its swashplate angle and makes full use of the engine torque to get all the power to the bucket no matter what. Thus, your machine is able to fill a 2 yard ditching bucket at around 1/2-2/3 throttle. If you fix your computer, you will find that it would struggle to fill a 1 yard toothed digging bucket at the same throttle level, because the computer will decide that it doesn't want to load the engine and it will reduce the pump flow to almost nothing. -This computer phenomenon is much worse in newer excavators because of all these emissions regulations. When diesel engines are put to work, they like to make a little black smoke, and even the tiniest bit of black smoke kills environmentalists. Thus, the computers in modern excavators shy away from even going near the engine's max torque. And so, the pumps decide to play dead when you get into tough digging. It's why some people still hang on to their old Koehrings and such. In heavy digging, new fancy low emissions machines simply cannot compete with the brute force of the old fixed displacement, computer-free excavators. P.S. The pond I was digging in had some real intense conditions. I was digging in a mix of sand and gravel, and as you may know, wet sand/gravel mix is the densest stuff you ever dig. To make matters worse, the pond had a 1/2" thick solid carpet of some impossibly tough moss that really worked my excavator to tear it.
The engine RPM is determined by the throttle lever on the pump. There is a minimum and maximum set of screws that limit the amount of travel the lever can make. The engine will be OK right up against the maximum screw. As far as it wearing out faster, that is determined more by load on the engine, maintenance and damage from outside factors such as oil change intervals and overheating. Since your computer may not be letting the hydraulic system fully load the engine you shouldn't have any problems there. The oil changes and overheating are fully in your control. You would be far better off getting a the system working properly so you could reap all the production the manufacturer has made available to you. Good Luck!
The engine RPM is determined by the throttle lever on the pump. There is a minimum and maximum set of screws that limit the amount of travel the lever can make. The engine will be OK right up against the maximum screw. As far as it wearing out faster, that is determined more by load on the engine, maintenance and damage from outside factors such as oil change intervals and overheating. Since your computer may not be letting the hydraulic system fully load the engine you shouldn't have any problems there. The oil changes and overheating are fully in your control. You would be far better off getting a the system working properly so you could reap all the production the manufacture has made available to you. Good Luck!
Older machines with no computers I agree with Sultan that full power is mostly not cost effective. Most of the time a computer is a detriment to getting the power you need regardless of throttle setting. I run 1/2 to 3/4 throttle on my Hanix and get the same digging power as at full throttle but the swing is slower. If I'm loading a truck I speed it up to get faster swing. I think running at full power is a waste of fuel and wears out the machine faster and is more tiring to the operator. Faster speeds often lead to more mistakes.
I know we tune up the majority of cat exc. we sell and work on, Well the 312 and bigger. We not only put the reliefs at the high side of spec but change the torque setting in speed dial 10 to 120% and then change the PRV settings to 60 low 390 high. These keep the PQ curve of the pumps higher longer. On the smaller exc, the numbers may need to be backed off if the engine lugs too much. most customers love these settings. They never complain about too much power. These settings will keep the pump pumping longer before going into a stall condition. Because the engines try to maintain RPM regardless of load, it will now dump more fuel into it until it maxes out, then the RPMs drop and the pumps will back off to gain the RPMS back. This is where it is making max power and boost and on older engines blowing black smoke. The fuel economy goes down but most operators don't complain about this, they complain about low power. Now in light digging the pumps wont demand the power so the fuel economy will be normal. The engine only burns enough fuel to do the work demanded. At a throttle setting less then 10 the PRV is fixed so it is a constant load regardless of demand. I have no idea how operators operate, just what they complain about when its not working right.
Hi swampdog, you said that you have an EX270LC if that is the case there is no computer that controls the pumps. There is only a computer for the auto idle system and the work modes . The modes is the three position dial switch that you select either L,E,P. [ light, economy, power] the decal is probably gone by now. The auto idle switch and travel speed switch which are usually seized or don't work because of dirt in the contacts, can be taken apart and cleaned. There are two pressure switches on the main control valve that are telling the computer that you are using the attachment or traveling. The computer activates the three solenoids in the rear of the machine by the pumps. The solenoids activate the two hydraulic cylinders as required. One cylinder is for auto idle and L mode the other is for E mode. The travel speed switch being in rabbit uses the third solenoid to allow the pumps to stroke just about five degrees more only while traveling. If the travel speed switch is in turtle, the engine slows down to E mode if only traveling. If you use the attachment while traveling in turtle the RPM increases. If the electrical part of this system doesn't work you only lose the options. You just operate like in the good old days, or as you are doing now. That's why it was hard to see the -2,-3,-5 and ZX models replace them.
Machine, that's very interesting. I think that I more or less understand what you are saying. It sounds as if it's not a big disadvantage to continue operating the machine manually, with the hand throttle. And that just cleaning the contacts on those two switches may restore the automatic features of the machine. (The decal on the mode switch is still there, although it is quite blurry.)
If i recall the old dash 2s had an ecm in the engine bay right under the muffler and the mufflers would always rott out in the bottom and cook the ECM
Swampdog. If you have a manual throttle then you have an EX270-1 series. The mode switch is for E mode=reduced rpm. I mode=for a further reduced rpm. Some guys do run them in E mode for better fuel economy. There is no ECM in this machine. No computer controlled pumps. What you have is 2 hydraulic plungers on your throttle linkage that when in E mode it activates it and reduces engine RPM. Same with I mode. The I mode plunger is also used for auto idle when activated. The 2 speed travel when in turtle will use the E mode plunger and slow the engine down while another solinoid will go to the pumps to change the max swash. To check the solinoids that activate the plungers check for 24v. Check for open or shorts to the solinoid. if you have 24v and there are no shorts or opens.(don't know the resistance) then put in full rpm and run the ground to the frame to see if it works. Hitachi controls the ground in a Control Unit in the cab. FYI Hitachi Ex series machine 100-450. Hand throttle=Dash 1. Push button throttle=Dash 2 or 3 Dial Throttle= Dash 5
throttle position I dig around utilities and work around people everyday and would NOT EVER decrease my rpm`s below full except when it is not moving. I f you are a competent operator(and mostly everybody on here is,) there is no need to ever move your rig unless it is running full throttle. To the trained proffessional operator that is the most cotrollable mode. Respectfully, Scott
I worked for The City Of ____ once upon a time, we had three crews each had their own hoe and when the supertendent would show up you had better have your hoe at full throttle or he would throw a fit. :shf He would throw his hat on the ground kick dirt, and I heard him tell one operator twice that if he ever caught him running at half throttle again he was fired.
In some situations full throttle gives the best results, but for other conditions I find it unnecessary. For general digging in sand, I find full throttle gives a 10% production advantage, and 35% higher fuel consumption compared to 80% throttle. Why go at full throttle when 80% throttle does almost as much work with MUCH less fuel. Your circumstances also dictate how you operate. If you're just trying to maximize production to please the boss, you'd go at full throttle. But if you're your own boss, and have to pay your own fuel and maintenance bills (like me), you'd work at a different pace to minimize operating costs while still getting the job done. P.S. Now digging at half throttle is another story. That is a bit stupid because, there are no fuel savings compared to running at 80% throttle, and you're just wasting your time going slower than necessary.
throttle positioning I wasnt reffering to maximum material moved for engine for given rpm, I feel its best to run full throttle in any situation for a variety of reasons. The first one is controllability, when using multiple cicuits you have enough flow to accurately operate both without sacrificing feel to any other. 2 is feelling for utilities, in this operation you are only moving the levers a little bit so when you feel something the valves have less distance to close. 3 it amazes me that so many people on here feel full rpm means operating erratically and in a hap hazard fashion, nothing could be further from the truth, quite the opposite is true. I just like to control the machine myself not the computer. respectfully scott
puppies???
I Really agree with this. I've put about 12000 hours on the 150 myself and it goes to full throttle as soon as I start it. When it was new I played with the four modes for a while especially when lifting but the slower speeds change the reaction to the controls. When you're doing something delicate you want the controls to respond exactly the same every time. I think this is safer anyway. We will ocassionaly run the economy mode but it quickly becomes frustrating.
throttle placement very well said 150, I am very glad you agree with me. This is a extremely pertinent subject to me for years now. I find it amazing that conceptually other people who run hoes have a hard time comprehending my point, I would`nt ever tell anyone else how to run and I am not doing that now I am glad you agree with me, I was feeling a little on my own here.
Most of the operators I've talked to run full all the time. My operator is same way and he usually runs the machine these days, not that we have much work these days.
With load sensing hydraulic systems you can run the machine at any RPM you want and get the same feel. Your functions may operate slower when maxing out the controls, but a properly adjusted hydraulic system will deliver point perfect touch at any RPM. I do agree with two things stated here. First you run the machine the way your employer wants it run if they specify such a thing. Two is that you should know your machine and run it the way that is the most efficient for the operation you are trying to accomplish. What is really nice about his forum is hearing the different operating philosophies presented. Some I might try in the future.
running at 100% throttle only wastes fuel, especially on electronically controlled machines. if you look at a torque curve chart showing engine RPM and pump output, once the engine gets above about the 85% mark pump output is at max and will slowly drop away when given more revs. so giving it full noise will do nothing for you.
In my experience; if you are working with a pipe crew you haven't worked with before, if you don't run wide open, they think you are afraid of the machine, and they might not trust you with their lives. When that gets back to the boss, next stop: unemployment. In a perfect world the people in the trench would know it doesn't mean you're afraid of the machine, or they would talk to you about it. But we don't live in a perfect world. Not every hoe (excavator) is hogging out dirt in some huge mine site or borrow pit. When you're working around people or existing utilities if running the machine at full throttle makes the machine smoother then that's what you have to do to get the job done regardless of "torque curves" or fuel economy. If the controls do feel smoother to you at lower rpm than do that. When you are in the seat of that machine YOU are going to be held responsible for injuries or damage, because you are supposed to be in control of that machine. So run it the way is best for you to control the machine.
throttle placement Excellently put, as usual from you Mr. head, no nonsense, sraight to the point and true. I respect that
I agree 100%.
i get what you guys are saying but machines are designed to run within certain perametres. running them outside these causes premature failure of components.
True too. That's why I adjust engine rpm to suit the job.
I've always run 100%. Obviously if i'm doing little piddly work i'll turn it down, but otherwise it's wide open. We have never had any major failures on any of our excavators (2 Cat 320CLs, Cat 320BL, Cat 312CL, Cat 308CR, Cat 302.5, and a JD 230C) and they are always run wide open. I haven't ever seen an operator that didn't. The 320BL we have has 18,000 hours on it, and it's always been run wide open and we haven't had any failures with it.
most run at rated. generator engines in particular are designed to run rated speed. a hydraulic system is similar and should be run rated but i often times run my machine slower speed but usually when doing some tricky thing (moving something-picking pockets etc.) ........ and it's quieter!
The engines and pumps are designed to run at rated speed and output all the time. The only limiting factor is reserve cooling. This is virtually none. About 10% reduction of air flow through the radiator will make you system overheat. Keep them clean and change filters and oil when specified by the manufacturer and it won't hurt a thing to run full throttle all the time.