Combines N6 questionsIJIJIJ

I would hesitate to run the machine past 2200 rpm, the older 670's were throw away engines because they ran too fast. See other posts My 84 N6 runs at 2100. There may be a slow down kit for it. I'm not sure this is any help with the radiator but mine looks like you take into the engine comaprtment.

Ouch!! 2700rpm on that engine is not good. Isn't this the engine that is famous for stretchin rod boltsIJ If so, I would run the bottom end on it before I had to depend on it too heavily. look at the bright side....with the engine out the radiator is a snap....no the rod bolts are what snaps......well you get what I mean.

I just read your previous post where you bought the machine. If it truely has only 110 hours maybe your okay...provided they used new rod bolts when they went back together. This high rpm could explain the new engine 110 hours ago. I would be curious what the failure was that caused the engine rebuild. I bet it was something other than just high oil consumption. OKFarmer

What do I have to get to put this slow down kit onIJ How long will the engine last running this fastIJ 1500 hoursIJ Original went 2490 hours.

I imagine you could email Dan Hurtt at Hurtt Equipment in Hoople ND and he could tell you. Just a guess - The drive pulley must have to be changed to maintain RPM for combine operation and the travel of the pump arm lessened. You might want to bump the HP too. You may be able to find the change over in a junk yard so it would not be too bad in price.

Are you sure it is a 670I and not the HI like the 7080 and 7580. They ran fast for a while. Slow it down. I think ours runs a 2500 and pulls down to 23 or 2400 in the field. Running down the road, we don't like to run it as fast as we could. Also put a spin on bypass filter on it.

As far as slowing the engine down you need a pulley off of a N5 or R50. These pulleys are larger in diameter to compensate for the slower engine speed. You then need to pull the injector pump and send it to a diesel shop and have them recalibrate the pump to run at N5 rpms but still give you 220hp. lee at Mid West diesel in Ft Dodge did mine. Reconfiguring the rotor according to the Hyper Mods button will also reduce the load on that motor plus give you better over all performance. Pete Hinrichsen

It is sounding to me like you have a '82 or newer N6 that allready has slower rated speed. If it has the American Bosch fuel pump it will have a rated speed of 2400 RPM which would explan the overload beaper coming on from 2200 to 2300 RPM range. Overload beaper was allways enabled on these early machines. High idle no load on the Am Bac system should be set at 2600 RPM plus or minus about 50 RPM. I have only slowed down one of higher reving Roosa Master equiped machines. This requires the PTO pulley off a N5 or a '82 or newer N6. You'll need belt also. The qualified pump station I took pump to had to change govener spring to get proper fuel flow at the reduced pump RPMs. I also did one tractor engine by just turning in the high idle screw. I dynoed that tractor before and after. This worked fine with the pump setup on tractor but will not work very well on combine. I might add that you need to practice old school diesel engine knowledge with all these engines. Warm them up at or near idle. A great percentage of these engines that lost a rod lost the bearing first. Many of these you found they had short engine oil filters and element inside filter was blown. longer filters were put into production quickly and an improved filter bypass valve a while later. You still need to warm these engines so oil can flow freely where it needs to go. It was never to hard to pick out the operators that were going to lose an engine someday. I think the best way to see if bearings have been damaged is to tear it down. If new bolts are installed be sure to burnish them in by tightening and loosing a few times per bulliton. Proper torque and procedures are extremely important on rod bolts. Best of luck with your N6.

Already has a bypass oil filter. Roosa Master injection pump. I have no book for the thing so I will have to get one. The last numbers on the serial number are 01894H if someone can figure the year by that. It has big numbers on the hopper too and I don't no what year that changed.

I think what the guy meant about bypass filter is get rid of the lubefiner canister type and replace with spin on type of later machines. Some canister type filters had pluged outlit fittings which could cause gasket to blow which would dump all your oil. That would be an earlier machine with that S_N and brand of pump. Orange engines in '79 and black in '80. Maybe someone has stuck N5 engine in there and recalibrated overload module for the slower reving engine. Take numbers off diesel pump and maybe I can tell you. You could also take photo tack reading of main shaft. Rated speed of mainshaft is 1350 RPM. See what engine is reving with mainshaft at 1350. Maybe you can trace back the owner or owners to see if engine has been swapped around or monkeyed with. Radiators do slide out threw engine compartment. Good luck