988G-988B compare for superior loader design!

[junior]

http://i20.ebayimg.com/02/i/000/78/49/3b81_1.JPG

http://www.machinerytrader.com/images/Machinery/fullsize/74251613.jpg

i am not talking about their capacity, but about their design differences. look at the photos above, i think z linkage is better for high force, also double z linkage is better than all. so the smaller 988B is be better for under heavy works? also the main boom of 988G is to long(you can understand it that in the photo above the distance between the front tire and the rear of the bucket is to much), i think it is designed for loading the bigger trucks-the higher ones, but i think is a mistake about stability.(on the other hand i see a 988G with a shorter main boom in this picture but it is attached a fork on it for big stones; here; http://image44.webshots.com/45/8/2/92/350880292tIVmnH_ph.jpg?action=&track_pagetag=/page/photo/rides/rides/&track_action=/Shortcuts/FullSize)
also 988G has only one joint between main boom and bucket, but the old type loaders like 988B has two. and one joint is means unbalanced force especially if you are filling or forcing the bucket with only one side.( you can see the difference here; http://image46.webshots.com/47/0/50/57/376605057twSJyS_ph.jpg?action=&track_pagetag=/page/photo/rides/rides/&track_action=/Shortcuts/FullSize
the one in the middle is old type like 988B(better i think) and the sides are like 988G)

and here comes three questions;
1)at last what do you think, which one is the better,988G-988B ?

2)which loader is the best you think in 988G's class? CAT 988G, CAT 988H, VOLVO L330E, KOMATSU WA-600, KAWASAKI 115-ZV, or any others.

3)do you know about fuel consuptions of them, can you compare them(between these models and then generally between differences of the manufacturers)(for example is it true that cat machines' consumption is not economical.)

thanks for comments...

[Tigerotor77W]

Junior -- first, the two webshots links you posted don't work for me. I don't have access to see those images.

1) "Better" is somewhat relative -- you'll find one operator who swears by the old iron and another who says the newest thing is best. I do know that the 988G will outperform the 988B... it has more than 100 more horsepower, weighs 15,000 pounds (7.5 tons) more, carries a larger bucket, and has over ten tons more breakout force.

2) 988H offers some advances in technology and is emissions-compliant. It also offers a 3.88 meter boom, which is shorter than the standard 4.25 meter boom on the 988G. The Komatsu WA600-6 is the replacement of the WA600-3 and is quite a bit larger and more productive. The Volvo L330E is being upgraded to the L350F this year, which features a new cab and transmission.

3) I don't have specific numbers. I do believe Cat runs a little more fuel than the others, but usually, production studies show that it's about equal. I do know that fuel consumption in the smaller H-series (950-980) is actually slightly better than Volvo's in the same size classes.

As for your points about the monoboom, it's not entirely true that the monoboom is weaker than the standard z-bar linkage. Stress is actually dissipated much more effectively on the monoboom than on z-bar linkages.

[komatsukid]

Well said Tigerotor. I have run large loaders for along time. To be truthful I think it would be what the operator prefers. To pick one machine out the manufacters you listed would be silly, because each one has its pros and cons. If I could take the cab off the Volvo, The quickness from a Komatsu, the low end power from a Cat and the hydraluic swstem from a Volvo that would be my perfect machine. But again thats my opinion.

[farm_boy]

I do know that fuel consumption in the smaller H-series (950-980) is actually slightly better than Volvo's in the same size classes.

I going to have to disagree with you here on this one, at least the 980H. The 950-972 did improve in the area of fuel consumption :yup and are within a couple percent (better/worse) than the Volvos. This improvement of fuel burn I would attribute mostly to the PCLS hydraulics system and NOT the T-III ACERT engine. The reason I say this is because of the 980H and its horrible increase in fuel useage over the GII. For the most part nothing really changed going from the GII to the H other than an electronic transmission, new cooling package and a T-III ACERT C-15. The hydraulic system remained the same open center system with gear pumps. The people that I have talked to that have purchased these new H's are not impressed with their fuel consumption (or productivity) when compared to the GI's and GII's they replaced. One of them actually referred to the 980H as a "fuel sucking monster."

I would be very surprised :eek: if there is a 980H out there that is using less fuel (and doing the same work) as a Volvo L220E (or a WA500-6 or 844J). Not taking anything away from the 980's reputation as it has been a corner stone in the market as a 7 yard loader, but the current machine is getting long in the tooth. It has the least amount of HP in this size class and has an inefficient hydraulic system that is shared by only one other competitor in this size class.....and that's Kawasaki's 95ZV.

[komatsukid]

does cat use fixed displacement gear pumps to feed their hydraluic systems?

[farm_boy]

does cat use fixed displacement gear pumps to feed their hydraluic systems?


:yup Sure enough....in the 980H anyway. The main hydraulics are open center gear pumps. The steering system load sensing though.

The other H series loaders are PCLS with piston pumps.

[komatsukid]

open center systems are the way to go because they only pump oil when it is needed, thus improving fuel econ.

[Tigerotor77W]

I going to have to disagree with you here on this one, at least the 980H.

I have a lot to learn from you! :yup Is the hydraulic system exactly the same on the two machines?

And is there a... good tutorial on hydraulic systems -- both cylinders and transmiissions out there? (Or do you yourself know and care to share the knowledge?)

I was told incorrectly by Cat marketing, then. I've got to figure out how to get ahold of the guy I talked with.

[loader950G]

Junior where did you get that picture of the 988b? I was just wondering because i have ran that loader before it belongs to a company named Kellys Railroad Service, which i do alot of work with. Thaey and the company i work for do alot of railroad work including the train derailments.

[komatsukid]

im not sure if both manufacters use the open center system. do you have any wheel loaders? i know volvo uses this system. one good way to see this work is if you run a loader up a grade and pull the hoist lever back the machine should loose vary little speed, if any at all, this is because the pump(s) are only pumping the amount of oil need for the task at hand and not over pumping oil. in a fixed displacement system the pump(s) are always pumping no matter if you are pulling on the levers or not, thus depreciating fuel consumption. i hope this helps.

[Mike J]

"open center systems are the way to go because they only pump oil when it is needed, thus improving fuel econ."

open center systems pump all the time, the oil that is not used is sent back to the tank.

Closed center systems only pump the amount of oil that is needed.

[junior]

Junior -- first, the two webshots links you posted don't work for me. I don't have access to see those images.

you can get them without login nevertheless they are here;(i can't upload because of my upload limit)
http://img147.imageshack.us/img147/9111/1753fb8.jpg

http://img147.imageshack.us/img147/2479/286mj8.jpg

Junior where did you get that picture of the 988b? I was just wondering because i have ran that loader before it belongs to a company named Kellys Railroad Service, which i do alot of work with. Thaey and the company i work for do alot of railroad work including the train derailments.
it is a 1990 CAT 988B and can be probably your machine, from Phoenix, Arizona.:) Is on selling, tell us it's secrets:bouncegri , is it to be worth of that money, isn't it to much(99,000$), come on give us a inspection report!:thumbsup here comes it's ebay link; http://cgi.ebay.com/1990-CAT-988B-WHEEL-LOADER-AZ-NO-RUST-MACHINE_W0QQitemZ150080666982QQihZ005QQcategoryZ92 152QQcmdZViewItem
(i think you are happy now, i can imagine your laugh on your face:) )

[junior]

this will be interesting, lets get comments; http://global.volvoce.com/compare/cc1.aspx?utype=u&sel=563,12,342,908,1507

[komatsukid]

you are right i got the two mixed up, sorry my mistake. the closed center hydraluic system is the way to go.there is a vary good tutorial on this subject at volvo.com anyway thanks for the correction Mike J.

[alco]

Please fogive me for posting this here too. I have asked this on a couple of other topics.
Xing, you said:"As for your points about the monoboom, it's not entirely true that the monoboom is weaker than the standard z-bar linkage. Stress is actually dissipated much more effectively on the monoboom than on z-bar linkages."

Please forgive me, but I am a bit sceptical about this in certain situations. How do you feel the monoboom will stand up to excessive twisting from handling pipe? We run two 988F's and will be replacing one soon. They spend most of their life handling pipe up to 100 feet long. It is not unusual to be carrying a pipe with the grapple above the cab and have the ends of the pipe bouncing off the ground. Even at slow speeds, we operate in such rough ground that there is nothing you can do about it. My personal thoughts are that we would twist the monoboom apart in no time.

How do you guys feel about this?

Brian

[Tigerotor77W]

My personal thoughts are that we would twist the monoboom apart in no time.

I've crafted a response and am checking it with some colleagues. In my mind, my claim makes sense (in certain applications), but I want to make sure I don't make the same mistake of not putting words where my mouth is again. :) I admit that my original post was not quite as correct as it should be. (Which teaches me to watch what I say and how I say it.) I'll get some confirmation on this and get back to you.

[Tigerotor77W]

Okay, so here's the original reply I had:

The Cat literature promotes a three-times advantage of a monoboom when corner loading a bucket in certain applications, because the stress is dissipated through the entire box section, rather than up one arm, through the torque tube, and up the other arm. From an engineering base, this somewhat makes sense: it is easier to twist a design that looks like an H than it is to twist a big chunk of steel. (I had such a design typed out, but the text editor didn't like the spaces... so the attached image will have to suffice for now.) For instance, if you made the design out of Legos and tried to twist it (as you would wring a towel), it'd probably give quite easily. Now if you took a cordless phone (plastic rectangular solid) and tried to wring it, it might not budge. The image attached puts this into an image: if you grab the top and bottom of each boom type and tried to wring it dry, the monoboom would deflect less. Granted there's a difference in dimensional scale, in material, and in force, but the concept of stress dissipation is the same.

Hopefully that makes some sense. Whether this is always true, or if it would hold true in your situation, may be a different matter -- but give your dealer a chance. If he seems unsure, ask him if Cat corporate (the product group boys) know of other uses similar to this intended one.

[Lashlander]

Thanks for the information. I've heard rumors that Cat is going back to the old designed boom on some of there loaders. If thats true then why? :beatsme

[mwhyte]

why the big fuss about the L350F? looks a dam sight better and a lot smoother and comfier than the 330E, but would rather have the CAT or komatsu. Im only the employee, so no say in the matter

[John C.]

The statements about open and closed center hydraulic systems are both wrong.

What you are talking about is variable displacement systems. The old wheel loaders used gear and vane pumps in all kinds of applications. These pumps are fixed displacement, meaning they put out the same amount of oil per revolution no matter what the pressure. The higher the pressure the more horsepower it takes to move the oil.

It has only been with the advent of advanced technology hydraulic systems in excavators that variable flow systems have been installed in wheel loaders and it has been too slow to come at that. Piston pumps can be set up to put out more or less oil depending on the design of the system and circumstances of the operation. If you are not doing anything you can destroke the pump and save the horsepower and fuel usage. When you need it, the pump strokes up and puts out the maximum amount. When you have high pressure and not enough horsepower you can design the system to cut back on flow. When the implement has stopped moving the flow goes out over a relief creating heat and wasted fuel. A variable displacement system can be designed to destroke and only put out enough oil to hold the implement in place.

I haven't been into big loaders for awhile so I don't know what the new models have for pumps or systems. The older Komatsu WA600 had gear pumps, Cat 988Bs had vane pumps, Volvo 330s had pressure compensated piston pumps.

I have seen a monoboom 988H used as a log stacker and haven't heard of any problems in the boom yet. This machine is working in a paved yard but moves very quickly with 30 tons of logs in the grapples.

The photo provided in the first post I believe is a high reach machine. As stated earlier, the 988B and 988G or H cannot be compared. Not only is the size different but so is the technology.

As for fuel usage, one has to measure it in gallons of fuel used per quantity of material moved. It is usually easier to count gallons per shift but that doesn't tell the whole story.

[seo]

John,
When you mention a variable piston pump, is that a swash-plate style rotary piston pump?
SEO

[John C.]

That would be a variable "displacement" piston pump. It depends on the type of pump. It can be radial piston or axle piston style pumps and both can be fixed or variable displacment.

[ben46a]

If the 988B was superior, theyd still build it. a 988B is more comparable to a 980H size loader. 7 yard machines. Without looking at figures, I'd think that a 980H or G would outproduce a 988B in many applications.

[Geno795]

One other thing about variable dispacement hyd systems I have read is that Deere uses 3 pumps on the 844J like an excavator has for years. One feeds steering and brakes at all times. The other 2 split between boom and bucket depending on which one requires the most flow, thus giving them an advantage on break out power. I believe you will see all larger loaders go to that style system in the future. Cat used vane pump on 980G and switched to gear pump on 980H. I hear them called lead sleds and fuel sucking monsters most of the time. Eugene

[John C.]

Wheel loader hydraulic systems can be set up any way you can think of and all the manufacture's do it different and claim their is best. The problem with their claims is that it always takes a certain amount of horsepower to move a specified amount of oil at a specified amount of pressure. In short there is always a minimum amount of horsepower needed with the corresponding fuel use.

An example is that it might take one horsepower to move one gallon of hydraulic oil per minute at 1,000 PSI. If you are using fixed displacement pumps, your back pressure is usually at least a couple of hundred PSI and you are always putting out 50 to 100 gallons per minute. This is wasted fuel going up in smoke. Return lines to tank are big to reduce line pressure going back to the tank. Hydraulic return filters are large and usually in mulitple elements to take as much of the oil with as little restriction as possible. The basic stratagy over the years was that a wheel loader is always supposed to be in motion moving material and if it wasn't it was supposed to be shutdown.

Usually brakes are put on their own system. Steering is usually put in combination with other systems such as brakes or implements. Usually there is also a pilot pump involved. I haven't seen any wheel loader hydraulic systems that separate the bucket tilt function and boom up function. They are normally on the same pump and control valve. There could be something new out now that I haven't seen yet. Ride control is usually on the implement system also.

As I said earlier when you go to variable displacement pumps you save fuel by not moving oil unless it is needed. The problem with variable displacement pumps in loaders is that they are very expensive. I have thought that the piston units would be too expensive for small to midsize loaders but should become cost effective in seven yard machines and larger.

At any rate the real fuel issue I believe is in the engine. If the engine isn't efficient at producing horsepower, you have wasted fuel going out the stack and usually blow by gasses coming out the breather tube. Again the only way to measure efficiency in wheel loaders is by the amount of dirt moved per gallon of fuel.

[Digger992]

I think alot of fuel usage is in the operator's hands...We have guys that take longer and cover more ground to load a truck and we have a few that run a tight V pattern...The guys that run the tight V always load the same amount faster and alot more efficient,the engine isnt full throttle as long...I run our 992G production loader,they figure my fuel usage by Loads crushed weekly...That gives them cost per Ton and also Per Ledge...The funny thing is,its never the same Per same Ledge...

Kind of funny what John said about Hyd system's,I ran our 988F for a while with the engine on its last leg,it wouldnt hardly lift a full bucket...They ordered a new one and they also put in a new pump...It was like getting a new machine...My fuel usage dropped at least 30%...

[992G]

There is a 3.6m boom that is offered in a bulk loading arrangment. Also they offer a 10 yard bucket to go with it. Beware, for some reason this set up does not have the break out force as the other boom options. If the operator has never ran a H model, and gets on this bulk loading machine, there will be no problems. If another one comes in with the different set up, a big difference in performance will be noticed. Also, when running these machines, make sure to use the throttle lock. It does help.