koldkanuck is correct. The N7s had a larger engine with 270 hp. The big benefit other than the obvious extra hp was that the 685I engine running at the lower rpms has a lot more longevity than the 426.
The N6 used two different engines! The first group was the 670HI or better known as the 7080 and blowing up engine. The second group was the 670I or better known as the 8000 or R series engine. When you go to get parts their is a difference. The easiest way to tell them apart is the injector pump. The 670HI uses a Roosamaster pump and AC nozzles and the 670I uses the American Bosch(Ambac)pump and nozzles.
Wow, some great new info. Thanks. I too just read the PAMI report on the N7 and the CIH 1680, and for comparison, the NH TR96. I was laughing as I read the mechanical history on the N7 vs. the NH......
AC lowered the rpms on the 426 engine from 2600 to 2400 , around 1982 I believe. Didn't the 516 run at 2200 rpms from the start? I know from 1982 on they did for sure.
I have always wondered why AC didn't put the 516 in the N6 also, could of saved some warranty work on the earlier N6 models. A 516 rated at 220hp would of had a long life.
Same thing in the 7080/7580 tractors don't you think?
A 426 seems most reliable from 160pto horses or less.
I was thinking of the 7580. We had one and I liked it but it needed more hp. We didn't turn it up because we didn't want to blow the engine. They probably could have sold more 4W220's with that engine. I guess it didn't matter after they sold out to Duetz anyway.
I have a 1984 n6 that turned around 2450. It turned loose this summer with a lot of blow by and some water in the oil. I bought another 670i out of a burned (cab fire) n5. I am in the process of changing in this week. I was told it had 500 hours on the motor???????? I know it was rated a 190hp were the n6 was to be 220. I thought I might change the pump from mine to the n5 motor. My machine only has 1800 hours and is rwa and very clean. I have also been looking at a 1991 r60. Dont know what to do. We also have a 1997 9600. It was down more than the n6 until the last three days when the motor turned loose. I am knew here but have grown up around and loved the gleaners all my life. I run three deere tractors 4450 8770 and 8870. Here is the old girl http://www.youtube.com/watch?v=bwO8l-6lfIU
http://www.harvesting.com/combine/ go to gleaner mods, 84's much improved, still more improvements, double helicals, throw reverse bars away, cage sweep is junk, got hydralic reverser, if not junk, darn spendy to upgrade, what does cage look like gittin thin, ouch, got questions email in profile, give me a number will call ya, scott.
So how many cubic inches is the N7 engine? I have seen a lot of posts that say 685 C.I. but my appraisal book and various other websites say 516 C.I. The only thing I know for sure is the 270 horsepower. Thanks.