98j d5

With the load you are pulling it sounds like it has lots of hp. Pretty much all of them were turned up some and 140 is the low end for a 98j. When we were looking at buying another cat a mechanic in the palouse said 180-200 was pretty safe and a common hp for a turned up D5. Our 1974 D6C has a similar engine to a 98j except a different turbo and is around 250 hp.

I've read both threads and I'm finding it very hard to agree with anything I've read, as far as numbers. I have been a Cat field mechanic for 35 yrs. , and that doesn't mean anything, but just that. Here is what you need to know, that D5 98J, should be set at 120HP. That is right out of Cats. Fuel Rack Setting book. You can increase your fuel setting all you want, but at some point you will cook a piston. Especially when you have a constant load for long periods of time, like pulling farm implements. Your piston temp. is very critical, and you should be monitoring your exhaust temp. very closely when ever you start increasing your fuel setting. I hope this helps.

How do you gauge the power rating by saying its turned up to ***hp without putting in on a dyno...is there a set of pump measurements that are supposed to be pro-rated to power? (when new)

As far as fuel settings, you use a dial indicator and measure your rack travel. In a Fuel Setting Book you get the proper spec. for a particular machine s/n . Sleeve Metering fuel system you use shims to adjust the dimension, in Compact Fuel systems it's usually a threaded adjustment. When you start increasing your fuel setting over recomended spec. you have to be very careful. You can figure out the increase mathimatically, but a dyno. is your safest method, if you do not have a thorough understanding of the fuel system you are adjusting and a lot of experience at making these changes.

Screwing the rack setting up doesn't necessarily give you more power unless the engine is underated any way, you need extra air to go with it and to increase speed as well. So you may well end with up extra smoke and more machine wear for little gain. This is why the high horsepower ag machines have aftercoolers on them and different gear ratios. The best you can expect is to pull higher gears when ploughing etc, but for an earthmoving machine you only spend more on wear and do less work with the tracks spinning.

straycat
northidahofarmer is correct. i have been told the pacific nortwest at one time not long ago had the largest concentration of D6's in the world. i work with a guy who spent many years at caterpillar here. he talks about 140HP 9U D6's, motor grader injection pump with valves, rotators and seats. a turbo and air filter from a 98J while turning the D318 engines to 1850 RPM's. the 44A D6's they would take them down and remove the plugs from the mains and install piston nozzles, update the head install turbo and fuel it. he said on the later 98J's the dealer would order the tractor from caterpillar with the turbo. this way they showed up with the piston nozzles and turbo. all that was needed was to turn the fuel up. the 3306 would take it no problem, you could expect only 5000 hours on the final drives. transmissions would take a beating also. the D6D 3306 was pushing 250 HP it seems.

in this area you had to look far to find a 9U with no turbo. the 44A's and 98J's all had turbo's and had the fuel system altered. the guy even told me of a 185 HP D5B. like i said the engine would run fine, its the rest of the drive train that paid.

u-joint Thanks for the info. I agree, if an engine is properly prepared, and the necessary changes have been made for a substantial HP increase, the engine will be fine. I know that a 3306 is safe at 270 with an aftercooler. You mentioned that the final drives and transmission take a beating, what usually fails first? the bearings or the gears? Where I farm, steel tracked machines in agriculture are used for clearing and breaking new land, D7's, 8's and 9's. I would like to know what a D6D set at 250HP is used for, what is it pulling? Looking forward to your response, thanks for now.

straycat- u-joint summed it up pretty well, no one really worried about the 3306 engines having problems at the high hp, with a few tweeks they ran all right. Some of those 3306s with aftercoolers were turned up to 300. He is right that on the D5s the final drive and transmission take a beating. In the farming with steel tracks thread bleedinred mentioned a D5 98j years ago that put out 245hp on the dyno and it had transmission problems, and final bearings on both sides went out all within a short amount of time.

Another thing I will add about the old D6 9u and 44a is that some people would add a harmonic balancer onto the crankshaft and then run the engine at 2500 + rpm or something like that instead of the 1800 or whatever that was normal.

A 250 hp cat in my area would pull a pretty big chisel, a 10 bottoms plow and a 48ft cultivator with sweeps and pull it alright. Much bigger than that and you would be shifting down in low gears a lot.

Our D6C plays with most of our equipment, that 21ft disk chisel going in 6" in the biggest load we pull and it will go up most hills in 4th.

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