Evolution of the "226" engine

There's been lots of confusion and misinformation over the decades on the A-C "226" gas engines. Many (who think they know) have said that the D-17 is the same engine as the WD-45, just revved up some more. Well, both claims just ain't true. While many parts do interchange between them, some simply do not. The G-226 engine used in the D-17 tractor evolved from the W-226 engine that came from the WD-45. The changes were somewhat minimal, but nevertheless, needed to be done for reliability and performance. While the 4 inch bore and 4 1/2 inch stroke remained exactly the same, yielding the 226 cubic inch displacement, there were only three things that were changed in the new G-226 from the old W-226. The block, the crankshaft and piston compression were the only things redesigned. The block casting was stronger/heavier and had a horizontal reinforcing rib down each side. These reinforcing ribs are very obvious when both a W and G block castings are side by side. The G-226 blocks also have larger 3 inch diameter main bearings, instead of the 2.400"+ diameter mains used in the W-226. This area had to be beefed up to withstand the compression and rated speed increases. So, with larger diameter main bearing journals on the crankshaft, it was a stronger piece of steel. So essentially, the cylinder heads are the same, manifolds are the same, carburetors and camshafts are the same, as far as making HP goes. It took compression being raised (from 6.5 to 1 up to 7.25 to 1) and rated RPM (from 1400 to 1650 RPM) being increased 250 RPM to get the performance to where engineers and salesmen wanted to be. The W-226 produced 50.6 flywheel HP @ 1400 rated RPM in the WD-45 tractor. The same engine produced 56.1 HP at 1600 RPM and 60.0 HP at 1800 RPM, all flywheel HP. So, when the compression is increased, the G-226 makes 55.6 HP at 1400 RPM, only 5.0 more HP than the WD-45. But if you increase the RPM to 1650, you get 63.2 HP. And at 1800 RPM, you get 67 HP.  So, you see that the new D-17 engine compared to the WD45 engine (with both at their rated RPM) produces 12.6 more HP at the flywheel. When you add power steering to the D-17 (which it was Nebraska Tested with) it brings the PTO HP to an almost 10 HP improvement over the WD45 it was replacing, 43 to 53 HP on the PTO. The G-226 went thru a few improvements over the years, with the first of which being long reach spark plugs, then the full flow oiling system and finally the nitrided crankshaft journals, which resisted wear much better. I have overhauled many a D-17 series 4 tractor and never had to re-grind the crankshaft on the first OH.  In my opinion, that generation of G-226 engine was about as good as it got when it came to long life. I don't think any of the competition had 4000 hr life on any of their gas engines back then. The G-226 still lived on until March of 1976 thru the 170 and then in the 175 tractor, and by then may have been rated at approx 73 HP at the flywheel (61 PTO) at 1800 RPM. And to think, it all started in 1934 with the W-201 used in the WC tractor !!

Edited by DrAllis - 23 Jan 2023 at 6:35pm

The 175 gas (as far as I've ever been able to determine) was the only grind change since the 1934 WC. There have been different p/n cams, due to a bolt on gear or pressed on gear, fuel pump capable  or not and oil pump drive gear tooth count.

D-17 gas engines always had 63 FLYWHEEL HP from 1957 til the end in 1967. The actual PTO HP was less because of the "live" hydraulic system, which took away 2 to 4 HP compared to pre-S4 models.

DrAllis wrote: The 175 gas (as far as I've ever been able to determine) was the only grind change since the 1934 WC...

Fascinating!

Modern camshaft design could easily improve performance while actually reducing peak acceleration changes (Instantaneous Rate Of Change), resulting in less stress on the valve train and longer life.

Even a better flowing head would have been a major improvement.

63 engine flywheel HP is the bare engine, minus the generator and fan. A 10 HP drop to 53 HP at the PTO is totally acceptable. The engine is spinning every transmission gear, Power Director clutch & gears, PTO gears, hydraulic pump and finally the generator, radiator fan and power steering pump. All of those things take some HP to operate. So now you are only talking a 5 HP drop to 48 HP, which then goes thru the ring and pinion, differential and final drives. Every shaft, bearing and gear turned requires HP to do so. 

Edited by DrAllis - 17 Dec 2022 at 12:58pm

Peak torque of 211 ft lbs lugged down to 1,100 RPM's.

DrAllis wrote: Peak torque of 211 ft lbs lugged down to 1,100 RPM's.

Is that listed on AC engine’s specs bulletin? If so, where could one find such info? Listed somewhere on Nebraska test? Is it perhaps measured on tractor(WD45,D17) pto dyno? Mathematically figured ~ Torque=hp x 5252/rpm ? Or measured by AC on just engine dyno?

jvin248 wrote: . When I look up the D17 on "tractor data", why does it show such a severe drop from "63" engine horsepower to "48" draw bar (tested) horsepower? That seems like a significant loss from power steering/etc systems and friction. Error in the data? Or the testing firm used a fixed rpm for all the tractors so if a particular product used higher revving to achieve marketing hp the figures differed? Which got me thinking about sales figures for market impact (including market longevity), figures from the Tractor Data site: WC: 178,000 first sold at $1,300 WD: 131,000 first sold at $1,800 WD45: 90,000 first sold at $2,400 D17: 85,000 first sold at $5,400 Chasing higher horse power, at higher prices, reduced the number of units they could sell between model changes. By the late 1970s/80s on that other thread where AC refused to send their latest product to Nebraska Testing (sixteen tractors needed) -- that was likely a significant portion of their total production that year because unit sales had fallen so precipitously with the chase for larger tractors with more horsepower so they can cover more acres to "finally be profitable!"... .

DrAllis wrote: 63 engine flywheel HP is the bare engine, minus the generator and fan. A 10 HP drop to 53 HP at the PTO is totally acceptable. The engine is spinning every transmission gear, Power Director clutch & gears, PTO gears, hydraulic pump and finally the generator, radiator fan and power steering pump. All of those things take some HP to operate. So now you are only talking a 5 HP drop to 48 HP, which then goes thru the ring and pinion, differential and final drives. Every shaft, bearing and gear turned requires HP to do so.

Years ago in tractor brochures the manufacturers gave PTO horsepower and drawbar horsepower. Don’t remember seeing engine horsepower advertised in the seventies and eighties. I guess I remember seeing engine horsepower listed was about twenty to twenty five years ago. It was about eight years I realized the manufacturers more focus on the engine horsepower of tractors when selling then.
But I always look at the PTO horsepower of tractors I look at buying because it was the minimum PTO horsepower or drawbar horsepower that was needed listed in manufacturers implements and equipment brochures.

I think today to many tractor buyers are looking at engine horsepower and not focusing on the PTO horsepower and they are not really buying the size of tractor they need.

When Kubota entered the market they advertised engine hp - that is less alternator, hyd pumps and water pump.... a worthless measurement, but when they entered the market they leap frogged competition as those early buyers had no idea of eng vs pto vs drawbar hp... and still don't. It didn't take everyone else long to catch on and start advertising eng hp..  ( we lost a lot of sales to Kubota - we were selling 5020's -5030's at 21 and 26 Hp -PTO hp before we caught on that these were about 2 sizes above the same engine hp units - we didn't win any Einstein awards)  

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As I understand it, a "Z" code means 8.0 to 1 compression ratio, which should be a One-Seventy engine. So, the serial number should be 7- XXXX -Z  and that should be 1967 til 1973 ??   A D-17 engine serial number is 17- XXXX -M for a gasoline engine and maybe "V" for an LPGas engine and ran from late 1957 til mid 1967.   I think the 175 engine serial number would be 77- XXXX -V from 1973 til early 1976. **** EDIT: I'm a little confused on the 175 gas engines s/n.  My 175 owners manual gives reference to 7- XXXX- Z, which cannot be correct, as the compression code should be "V" for 8.25 to 1.  Nebraska Test lists the test tractor engine as 77100 with no letter code. So, if someone has a 175 gasser, could you please look at your engine s/n and report back ?? Thanks.

Edited by DrAllis - 22 Dec 2022 at 7:08am

1968 was the last year for the "E" series. Sometimes the Gleaner line had an engine before the tractor line. Example: F-2 had the 4-cyl turbo engine in Fall of 1977 (78 model year) and the 6000 series came in Fall of 1980.  *****   EDIT: If someone actually has a 175 gas tractor, would you please check the engine serial number for me ?? There is conflicting information between the owners manual and Nebraska Testing.  The owners manual I have says the engine s/n should read 7- XXXX- Z, which I believe is wrong. That is a 170 engine format, as the Z should be a V.  Nebraska Test says the tractor that they had, the eng s/n was 77100, not 7-7100-V, which I think it should be or 77-7100-V. Can any owner shed some light on this please ?? Engine s/n is stamped on the block just behind and rear of the carburetor. Thanks.

Edited by DrAllis - 22 Dec 2022 at 5:39pm

How do you think the 226 compares to other motors of the time?
Ford had the 134-172 ci  motor line that they used for a lot of years.