Desmo or Not: Ducati’s V-4 Panigale and Granturismo

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The 1,103cc engine in Ducati’s Panigale V4 is not only the foundation upon which the company is building its future. It represents a synthesis, the connection between past and present Ducati technology. The project is technically and functionally very sound; the 90-degree V is powerful, reliable, compact, and light. It’s flexible enough to be at home in today’s strongest production superbike, the 224 hp Panigale Superleggera V4; its 208 hp naked counterpart, the Streetfighter V4; and the successful Multistrada V4, which currently outsells its V2 counterpart despite its higher price.

The Panigale V-4 has proved so rational, strong, and reliable that Ducati’s R&D department decided to experiment with a non-desmo valve train. While Ducati and desmo are inseparably linked today, keep in mind that until the birth of the Pantah 500, Ducati also produced many spring-valve designs. The sporty Mk III 250, 350, and 450cc singles were available with both types of valve actuation starting from the early 1970s.

Ducati’s Desmodromic Domination

Then came the Pantah, Dr. Fabio Taglioni’s response to Ducati’s top management of the time. The other managers, who were put in place thanks to support from their respective political parties, offered no competence of any kind. Taglioni poured all his knowledge and vision into the Pantah project, and his prescience shows to this day: The current four-valve desmo Testastretta V-2 shares most of its basic design with the Pantah 500, at least in its lower half, its belt-driven cam drive, and its desmo valve actuation.

Taglioni also knew that the desmo design alone wasn’t enough. He worked hard to make the system suitable for mass production. His assistant, Gigi Mengoli, addressed the valve-adjustment process to make it more accessible and to extend service intervals.

Related: Ducati 250 Singles - CLASSICS REMEMBERED

With the Pantah 500 and its derivatives, Ducati moved to a much higher standard of both functionality and reliability. In the pre-Pantah days, unreliable press-fit crankshafts and poor quality control during assembly hurt the brand’s image. The Pantah changed that, and the desmo system added much to Ducati’s exotic, high-performance cachet.

Ducati has come a long way since, viewed by many as the Ferrari of motorcycling. But even more importantly, Ducati is slowly emerging from the no-man’s land that separates an artisanal maker from real industry. At slightly more than 50,000 units per year, Ducati is still at the midway point; a real industry should manufacture at least twice that, especially since Ducati has more than 900 workers.

Ducati’s New Granturismo V-4

Now we shift our view to the new Ducati V-4 Granturismo, and with it a return to a non-desmo Ducati engine. While purists may disagree, I view the Granturismo as a positive move. The new engine shares the same highly efficient thermodynamics that makes the V-4 Panigale desmo the most powerful naturally aspirated unit in production, with 215.5 hp at 13,000 rpm. But the V-4 Granturismo requires fewer man-hours for assembly, translating to both lower costs and higher production volumes. For the public, the V-4 Granturismo represents a more accessible way to participate in the Ducati myth, in terms of both price and maintenance costs. Is this the path to the “real industry” salvation?

At this critical juncture, it’s only natural that Cycle World should explore the basic mechanical and structural differences separating the V-4 Panigale desmo and the spring-valve V-4 Granturismo. Let’s break out the wrenches, take off the lens cap, and dig in.

You can’t tell the players without a program: Here we see Ducati’s Panigale V-4 desmo is a 1,103cc unit. Telltale visual clues include its deep oil pan, needed to ensure that the oil pump does not go dry even under the hardest World Superbike riding conditions. In street-legal Euro 5 trim, it generates 215.5 hp at 13,000 rpm. (Ducati/)
While the 1,158cc spring-valve Ducati V-4 Granturismo shares the same overall size and design of the Panigale V-4 desmo, it’s definitely shorter top to bottom, thanks to its more compact oil pan. Also note the arch in the intake runners. The V-4 Granturismo is fractionally heavier at 147.9 pounds versus 146.7 pounds for the Panigale. The V-4 Granturismo generates 170 hp at 10,500 rpm. That sounds like a big difference, but the two units generate about the same torque: 93.7 pound-feet for the Granturismo and 92.9 pound-feet for the Panigale V-4. (Ducati/)
The Ducati Panigale V-4 desmo heads are gravity die-cast, for both superior tensile quality and an extremely clean look. Cam drive is via Morse chain and gears; the camshafts run in three cap-type aluminum bearings. (Bruno dePrato/)
The V-4 Granturismo heads share the same basic castings and gear layout, a rational choice applied even given the different valve-actuation systems. (Bruno dePrato/)
The Panigale’s desmo cambox is a busy place, crowded with two cam lobes for each valve and their related finger-type opening and closing followers. (Bruno dePrato/)
Here we’ve removed the cams, better exposing the opening and closing cam followers. Those hairpin springs are a peculiar component exclusive to the desmo concept; they assist the valve-closing forks and help take up the play between the opening and the closing cams. Eliminating that play altogether would make the desmo system excessively rigid and risk breakage. (Bruno dePrato/)
Desmo 101: A Panigale valve and its actuation train—the opening finger-type and the closing fork-type cam followers. (Bruno dePrato/)
Nothing unique here: The Granturismo’s valves use the familiar coil springs. (Bruno dePrato/)
Desmo camshafts are unmistakable. Note that the large-diameter closing cam lobes feature a thinner section with reduced surface area: This is where they still bear against the follower, but do not operate the valve which is in its opening phase—a nice touch! Inlets open at 18 degrees BTDC and close 57.5 degrees ABDC; exhausts open at 60 degrees BBDC and close at 27 degrees ATDC, resulting in 45 degrees of overlap. Intake valve lift is 0.488 inch, exhaust valve lift is 0.425 inch. (Bruno dePrato/)
The V-4 Granturismo camshafts have no fancy features, but they do feature polydyne profiles to ensure valve motion is always under control; even the “spring” Ducati revs past 10,500 rpm. Both timing and lift are more moderate, with the inlets opening at 12 degrees BTDC and closing at 30 degrees ABDC. The exhausts open at 43 degrees BBDC and close at 1 degree ATDC for 13 degrees of overlap. Inlet and exhausts both lift 0.315 inch. (Bruno dePrato/)
The Panigale V-4 desmo combustion chambers are cleanly profiled, with the valves set at a 25.5-degree included angle (12 degrees inlet and 13.5 degrees exhaust). Inlet valves have a 1.338-inch diameter, exhausts 1.082-inch. (Bruno dePrato/)
In terms of overall design, the Granturismo’s head closely follows the Panigale desmo’s. Valve geometry is unchanged at 25.5 degrees included. Even the compression ratio is the same, a healthy 14:1. Inlet-valve diameter is 1.319 inches, exhausts 1.055 inches. (Bruno dePrato/)
The Panigale V-4 pistons are very light two-segment units, 81mm in diameter. Their crowns closely mirror the head for a very clean combustion chamber. (Bruno dePrato/)
The only difference between the Panigale and Granturismo pistons is the diameter. The Granturismo’s slugs grow to 83mm, resulting in an increased displacement of 1,153cc with the same 53.3mm stroke. (Bruno dePrato/)
Even though the desmo’s engine lubrication is semi-dry-sump, so there’s not much oil flying around in the crankcase, the crank’s counterweights are still polished. Crankpin diameter is 34mm, main journals are 37.5mm. Crankpin diameter is 34mm, main end journals are 37.5mm. (Bruno dePrato/)
Crankshaft forgings are the same for both engines, with a 53.5mm stroke and crankpins set at 90 degrees for a superior balance. The Granturismo’s crank isn’t as finely finished, appropriate since the engine delivers “only” 170 hp at 10,500 rpm. In both units the crankshaft turns backward to reduce dynamic engine interference with the bike’s front end. (Bruno dePrato/)
Con-rods on both engines are exactly the same, measuring 101.8mm center to center. (Bruno dePrato/)
Panigale V-4 desmo throttle bodies are oval; their total surface area is equal to a round 52.5mm bore. They also feature variable geometry to enhance throttle response over a wider range of engine speeds. (Bruno dePrato/)
The V-4 Granturismo also breathes through oval throttle bodies; in terms of area, they’re equal to a round 46mm bore. (Bruno dePrato/)

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