Combines 1680 HP BoostIJ

[DGJ]

I'm pretty sure here in the UK they have been running the higher horspower for a few years, not sure if it was the 1660_1680 or the first 2100 series that got the increased h_p

 

[Farm_Kid2]

I'm pretty sure the 1688 has more HP than the 1680, but I don't know how much more. I would guess that the other components are the same, but that's just a guess.

 

[tv140]

You should consider simply adjusting the governor on the pump. Try this first, you might be surprised how much better it is. Governor adjustment was needed on many of these early cummins engines in the combines. Tightening up the governor makes a world of difference.

 

[SDman]

Farm Kid2, I hope you don't mind me giving my 2 cents on this subject as I have been through this on several 1680s over the years with the Cummins engine. First off, consider the engine in the application. The 8.3liter_505 cu.in. Case_Cummins_CDC runs at 26-2700RPMs in the 1680, which was on the very high end of their RPM range(perhaps too high, some will argue). I have seen guys turn the fuel screw on these over the years, some with success, some not. I think considering the RPM these engines are running, I would not mess with the fuel screw. When Case came out with the 1688s, the engine HP was increased from 235 to 260HP, but more importantly, engine RPMs were slowed down considerably(rated RPMs went from 2500RPM on the 1680 down to 2200RPM on the 1688s and everything else since). This seemed to give the engines a lot more reliability. Now, what some dealerships did with 1680s was to monitor intake manifold boost pressure on them while they were working at rated load and set the injection pumps so that they ran 20-22 psi of boost. While this is far from a very accurate way for reading HP, it was about the easiest way to test HP on a combine engine. The best solution I found on Case combine engines(this applies to 1688s, 2188s as well) is to take the pump off the engine, send it to a reputable pump shop and have them install a "torque capsule" in the injection pump. It allows the combine engine to have a much better torque rise than they do without it. Usually, you will not have to increase the pump setting, the increasing torque rise will make all the difference. By the way, the separator_PTO clutch was beefed up on 1688s due to the bigger HP. The 2388s have the 3-speed rotor gearbox and longer rotor belt to deal with the x-tra HP as well. Good luck.

 

[Farm_Kid2]

SDman, Thanks for the info. That was just what I needed. I was planning on having the governor adjusted to keep from loosing so many RPM's, but I have not heard of the "torque capsule". Is that a retrofit part from Cummins or just an adjustmentIJ The guideline I've been given by an CIH dealer was 2720 +_- 20 RPM for high idle and 2500 RPM fully loaded in the field. Do you agree with that, or should we shoot for somthing else after the torque rise has changedIJ Could you tell me the info I need to supply to the pump shop to get this thing set up correctlyIJ The last thing we want is engine problems. Thanks for your help, I always learn from your posts.

 

[SDman]

Farm Kid2, be sure and find a pump shop that has dealt with 1680_1688_2188 pumps before and they can tell you far more on this than I can. The torque capsule is found on these engines_injection pumps on all the tractor engines, but not on any combine pumps(don't know why, either).Any pump shop that deals with Robert Bosch inline injection pumps will know what I am talking about. This capsule gives the engine a tremendous amount of lugging ability that it never had before. That was always my complaint on the 1680s with Cummins engines, once they started to drop RPMs, they fell like a rock(no torque rise to pull them through). Turning up the fuel delivery usually just made them use more fuel with no appreciable power advantage. As far as RPM settings, your dealer is correct. The only thing I would change after the pump rework is that engine RPM setting at which the "overload alarm" comes on. I recommend having it come on at 2550-2570 RPMs so you have a reserve of power in case you run a "big wad" through it. You change this by the phillips screw under the "E" on the digital tach. To see where it is set, turn the key on(don't start the engine),push the engine tachometer touchpad and it should show where it is set at. Moving the Phillips screw should change the RPM accordingly. Good luck! Oh, the diesel shop that does our dealership's work is DK Diesel in Watertown, SD(they know all about the torque capsule situation with Axial-Flow combines). If you need, I can get their phone n for you.

 

[Farm_Kid2]

Ok, I'll do some more checking with the pump shop and make sure they are going to install the torque capsule. I agree that the engine does seem to fall on it's face when it starts to lug down. We have always run the engine speed alarm indirectly by setting the rotor speed alarm. I didn't know that there was a direct engine speed alarm, let alone an adjustment. I'll get that set up like you suggest and it will probably be easier on the operator and the engine! Thanks a lot, Mike

 

[Big_Bucks]

I was told long time ago that combines don't have torque rise like tractors , because they have belt drives

 

[SDman]

Big Bucks, now that you say it, I have heard that before. However, the guy at the pump shop that alerted me to this problem on 1680s with Cummins engines claimed that the earlier 1680s with Navistar 466 engines did have the torque capsule(the Navistar 466s used the exact same injection pump as the Cummins 8.3l engines in the 1680s, namely the Robert Bosch MW inline pump). Perhaps the engines had different torque curvesIJ This never seemed to be that much of a problem on the 466-equipped 1680s, but then again, the 466 did not mind running that high of RPMs either.

 

[SDman]

One other thing when you get the pump worked on is to have the pump shop replace the bottom tin cover on the injection pump with the newer style cover with the support straps. The new-style cover is $15 or so, much cheaper than losing an engine due to losing all of the oil when the cover cracks when you are combining through the field and are unaware of a massive oil leak in the engine compartment. Good luck!