Over the past decade, tractor manufacturers such as New Holland, Case and Valtra have started increasing the horsepower offering in their four-cylinder ranges. However, it was in fact Massey Ferguson that first broke the 200hp mark with a four-cylinder engine, the 6700 S series, in autumn 2016.
Despite being on the market for several years, there still seems to be a stigma among many farmers and contractors, as to whether a four-cylinder tractor can match up to its equivalent-powered six-cylinder counterpart.
This argument isn’t just between four- and six-cylinder engines. We also see it with manufacturers between three- and four-cylinder offerings. This discussion is not unique to tractors either. We see it with the Claas Liebherr wheel loader partnership where four-cylinder engines have been pushed to 228hp on a machine with an operating weight of 19,500kg.
The debate is also widespread in the automotive industry where car manufacturers are pushing the power outputs of smaller engines.
To try to settle the debate, the Irish Farmers Journal put two of the most popular four- and six-cylinder tractor offerings on today’s market, the MF 6718 S and the 7718 S, head to head at the same tasks earlier this summer. To keep things simple, we will refer to the four-cylinder as the 67 and the six-cylinder as the 77.
Engines
The 67 is powered by a four-cylinder, 4.9-litre Agco Power engine. It has a rated output of 175hp. Meanwhile, the 77 is powered by a six-cylinder, 6.6-litre Agco Power engine. It too has a rated output of 175hp. Both tractors have Massey’s engine power management (EPM) which makes an additional 25hp available, bringing both tractors to a maximum output of 200hp.
EPM is an electronic engine and transmission management system that makes more power automatically available. EPM is essentially a boost which engages above 6km/h during PTO applications.
To get an accurate result on fuel usage, we put both tractors at the same tasks. Over the week, the 67 proved harder on fuel than the 77. This is fair given that the six-cylinder engine is naturally working under less load than the four-cylinder. One fill of AdBlue was lasting three to 3.5 tanks of diesel for both tractors.
Transmission
Both tractors were equipped with the well-known Dyna-6 transmission. This semi-powershift transmission has four ranges with six powershifts in each. This means it has an offering of 24 speeds in both directions. The tractors we had out had a top speed of 50km/h.
Massey has several nice features in this transmission. One is AutoDrive, which allows the machine to make shifts up and down automatically depending on the load. In fairness, we found that this function allowed for smooth shifting even with a significant load at the rear. The one function of this transmission that really stood out for us was brake to neutral.
When trying out the tractors on the Fusions when the bale was ready to be netted, this feature allowed us to bring the tractor to a complete halt by simply pressing the brake, before releasing it, and continuing to bale on.
Both tractors were fitted with closed centre 110l/min hydraulic pumps.
Cab
With the exception of an extra spool valve and the upgraded active mechanical cab suspension on the 7718 S, both tractors had the exact same cab.
Massey’s cab provides for a nice working environment. It may not have the most spacious feeling on the market but control layout and build quality is good. Visibility from both tractors was good, albeit the shorter bonnet on the 67 had the edge when looking forward.
Something a little unique from Massey is the number of options for changing ranges. The first two options were standard on both tractors. This was the power control forward/reverse shuttle on the left of the steering wheel. The second was by moving the T-shaped transmission lever forwards or backwards to change up or down through the ratios.
Although both tractors were “efficient” spec, both had an optional extra joystick. This multifunction reprogrammable joystick can be used to operate functions such as front and rear spool valves or the forward/reverse shuttle. If we were in the market for a Massey, we would certainly be opting for this joystick.
How do these tractors differ?
Aside from the number of cylinders in each engine, these two tractors have other differences such as wheelbases and their unladen weights.
The 67 has a 210mm shorter wheelbase than the 77. It also has a 213mm shorter overall length.
At 4.75m, the 67 has a tighter turning radius than the 77 at 4.85m.
When it comes to the overall weight, the 67 is 300kg lighter. Despite this, both tractors can be ballasted up to the same 12,500kg. Both have the same front- and rear-linkage lifting capacities.
The 77 comes as standard with Quadlink front-axle suspension, whereas the 67 uses a parallelogram-type Quadlink system. In our opinion, the suspension method on the 77 is more effective with fewer moving parts.
In the field
We tried out these two tractors in early June when the silage season was at its busiest. The tractors were tested on two Fusion 3 Plus combination balers, two Herron silage trailers and two trailed Kverneland mowers.
We decided to try the tractors on the Fusions to find out how they coped with some high-powered PTO work. Both were driven in 540 PTO speeds.
When baling, both tractors began to feel a draining of power when the bale chamber was approximately 90% full. It appeared that the 67 was giving in a little quicker than the 77.
To analyse how the tractors performed doing a variety of work, we also spent a day drawing silage. The draw was mostly close, and around 20 acres was hauled on a four-mile round trip. Both tractors sailed away with the 18ft trailers.
One of the fields being harvested had a gap which was a little tighter than the others. The slightly shorter wheelbase on the 67 meant that it was able to make it in this gap with one swing as opposed to the 77 that had to take a second swing.
However, the 77 had the newer type front-axle suspension, so it was more comfortable on the road than the 67. The heavier 77, with the longer wheelbase, appeared to be a little more stable on the road when fully loaded behind.
For farmers or contractors using 18ft or 20ft trailers, the nimble 67 would be our choice. But if going for larger trailers, the 77 – with the additional weight and length – may be the choice for stability reasons. At the end of the day, the decision between the 67 or 77 will be down to personal choice for the desired tasks, but both tractors had very similar power outputs.
Dyno test
To get an insight into engine performance on both tractors, we tested them on a Froment Sigma 5 dynometer.
It is worth noting that both tractors were still in their “running-in period” having had less than 100 hours each on the clock.
We were a little surprised with the results of the dyno test. As we can see from Figure 1, the 67 held out longer than the 77.
In other words, the four-cylinder engine had more torque back-up than the six-cylinder engine. But both engines did almost hit their rated horsepower.
Interestingly, the 67 had 11.6% torque backup while the 77 had exactly half with 5.8%. Overall, the results showed there was little difference in engine performance.
From our experience with the two tractors in the field, on the road and on the dynometer, there was no big noticeable difference in engine outputs. The 67 punched like-for-like all the way with the 77. Despite the 67 seeming to fall off a little quicker on the Fusion, it held on longer on the dynometer than the 77.
We mainly saw the differences from the physical wheelbase of the tractors, in which the 77 was slightly more stable when pulling the loaded silage trailer on the road over the 67.
Although only 210mm of a longer wheelbase, the shorter-nosed 67 was capable of taking the turn into tighter gaps in one swing with the silage trailer, whereas the 77 was not.
In terms of comfort, the 77 had a slight edge given it is fitted with the more effective Quadlink suspension and rear active mechanical suspension. The 67 only had the standard mechanical rear suspension and the other type Quadlink front-axle suspension. Overall, when choosing one tractor over the other, the number of cylinders should not be the deciding factor. The decision should be based on what the tractor will be used for.
The nimbler 67 would be a nicer yard tractor with a front-end loader, whereas the 77 would be better suited to the user wanting to carry out predominantly haulage of heavy loads, eg 3,500-gallon tankers, and heavy draft work, such as ploughing or operating a one pass unit.
In our opinion, this is where the 77’s stability and better performance on the PTO under loads gave it the edge.
The pocket rocket that is the 67 left us pleasantly surprised with its capabilities as a four-cylinder. This removed any initial doubts that a high-horsepower four-cylinder did not have a place in the market.
One might say it doubts the age-old saying, “there’s no replacement for displacement”.
To offer the fairest verdict possible, we have got the thoughts of a farmer and contractor who have been running both a 67 and a 77
Stephen Crochane is a dairy farmer near Bushmills, along the Antrim coast. His 6718 S is now in its third year while the 7718 S is just over one year old. So far, he has clocked up 1,800 hours on his 6718 S and 500 hours on the 7718 S.
Stephen explained that both tractors have a place on his farm, each suited to different roles given their characteristics.
He explained: “The 67 outshines the 77 for the majority of work around the yard, noticeably on the diet feeder. Its more compact stature means it is easier maneouvered”.
Both tractors draw grass during the summer and pull 16t dumpers hauling stone, this being a particular task where the 67 has the edge. Stephen said it feels torquier and more responsive than the 77.
He added: “The 77 comes into its own at heavier work, disc harrowing and pulling the 3,500-gallon slurry tanker. It feels more in control of the load behind.”
Interestingly, from Stephen’s experience, the 67 proves harder on fuel even at the same work as the 77.
“At the end of a day’s work, even with the difference in tank capacity, you’d notice the difference in consumption between the two when refilling with diesel,” he said.
Based near Castlederg in Co Tyrone, Alwyn Young is an agricultural contractor who runs a fleet of Massey Ferguson tractors. This fleet is made up of three-, four- and six-cylinder tractors.
In February, Alwyn traded in four 6616 tractors for four new 67 tractors.
He explained: “We work on a lot of smaller farms. As a result, we need a neat, compact tractor that is still high in the horsepower offering. The 67 is ideal for this.”
Alwyn uses his 67 models for hauling 3,500-gallon tankers, drawing slurry from farmyards to the umbilical system in the field, hedgecutting and pulling 18ft silage trailers.
However, he said that he likes to have certain tractors carrying out certain types of work. As a result, he uses his six-cylinder tractors for pumping slurry, driving his combi baler/wrapper units and mowing.
He noted: “After clocking up 1,100 hours on each of the four new 67s, they have burned 10 litres/hour of diesel and 0.5 litres/hour of AdBlue, on average. They are a powerful, compact tractor. In addition, these 200hp four-cylinder tractors are very sought after secondhand, so they hold their value. There’s definitely a place for them in the majority of contractors’ fleets out there.”