Max 8070 hp

...yes....we are all looking at you a little cross eyed and not answering...

I put this under FAKE news! The 426 didn't have reliability problems when it was pushed with hp, it had issues with rpms. Your 8.3 will have the same issues as does any diesel. It's a myth about 426 engines not handling hp. The ones that failed on the N6 and 7080 7580 were from the process of hardening the crank, that showed up with high rpms. Allis Chalmers cured that with a longer bolt, putting the nose of the crank under compression, and on the 8070 slowing the rpms.

Now here comes all the anacdotal replies of the 426 failures, that always come if someone defends that engine.

For best results, try and operate the Power Shift in 6th gear or Power Director in 5th gear low button. Do not weight it down heavily. Let it spin some.

I'm with ya KCGrain, I seen the same pulled the guts out of it, turned up weighted down then things finally come apart and Allis is junk , no proper maintanice, just rolling the black smoke, head shaking for sure

I'm no engine guru, don't pretend to be. But the 8050 I had was a good tractor for the 10 years it had the 426. It spun a bearing on the crankshaft around 3500 hours and I needed a 200 pto horse tractor. This was 2002 when corn was still under 2 bucks I believe. Instead of updating to a newer tractor for 50 grand or more, the decision was made to bastardize the tractor with a cummins 505 cubic inch 8.3. Our mechanic, an AC guy thru and thru said it would be roughly the same $ rebuild the allis or drop in a used cummins. My experience was better lugging, not horsepower TORQUE! And the fact it would fire on the second revolution when it was 10 degrees F was nice also.
If something happens to my 7045, I would rebuild the 426 in a heartbeat! You can talk about if you woulda done this or that the 426 would hold up, hardened, balanced crankshaft, better oil whatever. The tractor served us well and not a problem at all holding 200 horse in the 10 years after the conversion. Sold it locally to a guy who had a 8070 with the C word and he wanted another. Still going!

I'm not going to argue about engines however I do agree with Kc. To compare an early 80s 426 to an 8.3 Cummins is apples and oranges

That said. If you want a 225 horse tractor buy a 250 horse tractor and turn it down. You will never work on it. If you crank up a 170 horse tractor to 225 don't bitch when you are putting a trans or rearend in it. Those engineers weren't stupid.

Of course it's not comparing apples to apples, that's the point. When faced with the decision, it was a no brainer for me and the other traitors. (if that's what you want to call us)

What you need is a 71 series Detroit in it - or a 6V-92 then no worry about lack of power or reliability 

wekracer wrote: Well then sounds like you already know the answer so why did you ask the question. I'm not a purest but I do take issue in turning up tractors. My neighbor is always complaining about his 8070 because it's always at the dealer and he likes to turn the screw out. We have an L2 8050 and 8070 fwa all stock and have never had an issue. All do everything I ask. And they all start at 0 degrees if I plug them in.

My initial question wasn't what is better a 426 or a 8.3 it was basically how much of the upgraded motor can I harness in a straight frame tractor and do it without breakiing something.

victoryallis wrote: wekracer wrote: Well then sounds like you already know the answer so why did you ask the question. I'm not a purest but I do take issue in turning up tractors. My neighbor is always complaining about his 8070 because it's always at the dealer and he likes to turn the screw out. We have an L2 8050 and 8070 fwa all stock and have never had an issue. All do everything I ask. And they all start at 0 degrees if I plug them in. My initial question wasn't what is better a 426 or a 8.3 it was basically how much of the upgraded motor can I harness in a straight frame tractor and do it without breakiing something.

All depends if you are going to put any extra gained power to the ground or if you just want bragging rights and say the old girl is putting out 250 hp. The safe bet is to stick with the stockish hp the tractor was designed for. Especially since late 8070 tractors have the lighter final drives. Something close to giving the 170 PTO hp and I say that because I don't like to have to replace broken parts all that often. Like someone else said, if you want a 225 hp tractor go buy a 250 hp tractor just to be safe. I don't understand why anyone would want to stress their old 170 hp tractor to 225 or 250 hp anyhow. It will never live up to a modern 250 hp tractor in any way.

In fact I tell the pump rebuilder to not set a pump to 10% over like most rebuilders do. Guy who did my 670T inj pump for my L2 didn't listen and set it 10% or 15% above factory. I won't go back to him. I like stock hp because I know that is what my machine was designed for.

Remember what Mark (aka 427435) said about increasing torque and how it reduces power train life by quite a bit. I may not have agreed with Mark on a lot of things but that subject I certainly do.


Edited by Lonn - 28 Jul 2017 at 6:12am

victoryallis, what "pitfalls of an articulated tractor" are you referring to?

Tbone95 wrote: "What is the maximum horsepower that a 8070 could put to the ground"   First sentence of first post.  Nothing about should I redo a 426 or put  in a Cummins, nothing about bragging rights, nothing about purity, never stated a horsepower number he had in mind.  Simple question about the tractor chassis putting power to the ground, what can it handle.

145 drawbar hp safely, translates to 170 PTO hp. Is that simple enough?

But hell if all you care about is putting max HP to the ground the pullers are putting 1000 plus hp to the ground routinely. Good luck!


Edited by Lonn - 28 Jul 2017 at 7:17am

If your answer is the only safe HP is as designed, that's totally fine by me.  I don't have a single turned up unit on my farm, or even an engines swap.

tornado, turn it back to a slight breeze and have that beer.

Ya know it's not so much the fact of doing the repower as much of the fact that everyone I've ever seen are so hacked up and slobbed together it's horrible. Oil leaks, cables and gauges not functioning as they should. Hoods and panels all chopped up. I can't be a fan of that. Owning 6 8000 series tractor that earn their keep, and always looking to acquire one more, a tractor of that nature won't get a second look from me. That's my opinion, like it or not.....