Which is the best AC engine?

226 gets my vote.

1945 WC on full steel, WD wide front, WD45 power steering, 1966 D-17IVfactory 3 point.1967 D-17IV SC. 1973 rotobaler white top. orange top roto, model 90 combine,82S, four bottom plow.302 baler.

I have to say they all get my vote! Top of my list of the best would be the 301 and 226. But they are all incredible.

Blue Skies and Tail Winds
Dana

Not going to pick a favorite, haven't encountered one I didn't like. I do favor the 301 and 226 but the 125's in CA's are pretty impressive too. You can mow a BUNCH of grass with a tank of gas in the CA!

The 433T or 433I. Very high longevity, very low fuel usage, lots of torque rise and sounds like mad bumble bee. Biggest downside is cold weather starting

8070FWA,7080 BlackBelly, 7045,2 200s,D19,D17,G, WD,45,UC,7 AC mowers and lots more!
"IT TAKES 3 JD's TO OUT DO AN ALLIS, 2 TO MATCH IT IN THE FIELD AND 1 FOR PARTS!"

My two most useful tractors are my one ninety XT, with the 301, and my 7060 with the 426. Couldn't pick a favorite of the two, because both have specific duties that are really not so much interchangeable
Darrel

I agree with Ed on the increasing the 426 cubes to get more power. I also think if they would've offset the rod caps like the IH engineers did, they could've used bigger rods and rod journals and held together better at higher RPM.

Personally having both a 2800 diesel and a 670T, I really like them both. My vote is going to be for 426 though, so long as the RPMs are under about 2500.

But the 226 definitely deserves recognition. Thinking about how it started life as the 201 in about 1935, and was slowly morphed/adapted and used in tractors, combines, and cotton strippers through the late 60s is indicative of its reliability.

Charlie175 wrote:

Last 226 would have been in the 175 tractor (1980 last year).

45 amazing years for that design

I stand corrected!

Regardless of our preference of the AC engines, the "newest" ones are 37 years old and a lot of them are a lot older than that.

I wonder how many of the engines in tractors that are being built today, will be around in 37 years? I'm betting, not many!

426 mark II diesel engines

1974-1981(7040's 3500-670T, 7060's 3700-670I, 7080's 3750-670HI)

Deep-skirted block, Piston cooling system, cross-flow heads (exhaust/intake on opposite sides of head), Intake/exhaust valves alternate the full length of the head(less hot spots), Intercoolers drop intake air temperature after the turbo, high capacity oil cooler,

4.25"bore x 5"stroke,

16:1 compression ratio,

1310Lbs (3500-670T) net weight basic engine,

15qt (standard oil pan) crankcase capacity,

4qt-3500,10qt-3700/3750 oil filter capacities,

14qt (engine only) cooling system capacity

31qt-3500,32qt-3700,36qt-3750 total cooling system capacity,

64gpm@2400rpm water pump capacity.

Edited by AC7060IL - 17 Aug 2022 at 11:45am

injpumpEd wrote:

But the 426 came out in 63 in the D21 first as the 3400 naturally aspirated engine. I'm not sure of any other offerings back then. The 301 is a smaller version of the 426.

Right. In my opinion, the mark II version of the 426 seemed to be the best version of it?

WF owner wrote:

Regardless of our preference of the AC engines, the "newest" ones are 37 years old and a lot of them are a lot older than that.

I wonder how many of the engines in tractors that are being built today, will be around in 37 years? I'm betting, not many!

As for the engines I think they'll last as long as old engines no problem. Today's metallurgy, manufacturing methods and technologies, and quality is second to none. As for keeping them running as is with all the computers and emissions requirements, not so much.

Charlie175 wrote:

Last 226 would have been in the 175 tractor (1980 last year).

45 amazing years for that design

While the 175 tractor was built until September of 1980, the 226 gasoline engine option ended in 1976. It was the last AC gasoline powered tractor.

All good points made. I will add the 160 in our series II D15 has been a trouble free engine until the oil pickup came loose 54 years after it was built. Even a poor design oil pickup worked that long! AC made great engines IMO, across the line. Some better than others. The 433T and TI are good engines also, it’s fault, cold weather starting which is resolved by plugging in the heater for awhile before it’s used. Give it an hour and she always starts. I’m guessing the 201,226 were most likely the most produced engines. And the little engine with a big heart is in the CA, bullet proof, and as said mows grass on our farm with a 6’ belly mower like it’s not even there. Always thought the 426 was a beast but I’ve never owned one.

1968 B-208, 1976 720 (2 of them)Danco brush hog, single bottom plow,52" snow thrower, belly mower,rear tine tiller, rear blade, front blade, 57"sickle bar,1983 917 hydro, 1968 7hp sno-bee, 1968 190XTD

The 'best' engine is very subjective.

That's like saying "My Favorite Beer"... is the one I'm drinkn' right now...

The BEST AC engine ever made, is the one in the machine I'm operating right now.

...whatever that machine is, and whenever 'now' is...

There's at least a hundred different metrics by which one could 'rate' one against another... but in a 'best overall', there's really no point in attempting, simply because each motor design occurred as a result of the circumstance for THAT powerplant, at THAT time. Clearly, later generations of engines managed better fuel economy, and more power, but every step of metamorphosis along the way presented opportunity to advance, and AC certainly didn't IGNORE opportunities to improve.

The industrial engineering aspect of ALL AC motors is amazing- they really knew how to design things to be MANUFACTURED, and they didn't overlook how they were to be maintained and overhauled. It's this kind of thing that nullifies any notion of 'best', as every darned one of the Allis engines had it's characteristic superiorities.

Ten Amendments, Ten Commandments, and one Golden Rule solve most every problem. Citrus hand-cleaner with Pumice does the rest.

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