Iso Grifo

Iso Rivolta
Iso Grifo GL
Grifo
Production period:	1964-1974
Class :	Sports car
Body versions :	Coupe
Engines:	Petrol engines : 5.4–7.0 liters (224–294 kW)
Length:	4430-4600 mm
Width:	1770-1800 mm
Height:	1200-1230 mm
Wheelbase :	2500 mm
Empty weight :	1430-1610 kg

Rear view of the Grifo

The Iso Grifo is a sports car built from 1964 to 1974 by the Italian car manufacturer Iso Rivolta . After the four-seater Coupé Iso Rivolta IR 300 , Iso presented the conceptually similar, but sportier, two-seater Iso-Grifo-Coupé, a Gran Turismo for wealthy gentlemen drivers .

Development history

The engineer Giotto Bizzarrini , a former Ferrari employee, who left the Commendatore Ferrari's factory in a dispute and opened his own design office in Livorno in 1963, played a key role in the development of the Grifo . Bizzarrini designed a platform frame with box girders that - apart from a wheelbase shortened by twenty centimeters - was similar to that of the Iso Rivolta IR 300. American V8 engines were planned as the drive, initially a 5.4-liter V8 from the Chevrolet Corvette (the same engine was also offered in a tamer version in the large Opel models). Other technical components were also bought in: the steering came from Burman, the limited-slip differential from Salisbury, the disc brakes from Dunlop, manual five-speed transmissions from ZF Friedrichshafen , four-speed transmissions from Mancie or Borg-Warner or a three-speed automatic from Borg-Warner.

As with the Iso Rivolta IR 300, Bertone contributed the design of the coupé ; Specifically, it was the work of the young Giorgio Giugiaro , whom Bertone had recently appointed head of design. Giugiaro drew a low, feline hatchback body with gently rounded, tightly cut fenders and a clearly recognizable, slightly inclined roll bar. Round twin headlights were seen on the low front. The rear end was characterized by a large panoramic window that merged into a trunk attachment and tapered significantly towards the end of the car. Large air vents were provided between the front wheel arches and the A-pillar, which were chrome-plated on some models. The main features of the design go back to the Pininfarina Rondine I , a show car that the American Tom Tjaarda designed in 1963 on the technical basis of the Chevrolet Corvette.

The prototype of the Grifo was shown at the Turin Motor Show at the end of 1963 under the name A3 / L (Lusso). Its line already largely corresponded to the later series model; only the front section differed in the inclined headlights and a three-dimensional radiator grille. Between the front wheel arch and the A-pillar there was a conspicuous ventilation opening, which was covered with individual chrome-plated struts and exposed an exhaust pipe located behind in the style of American "sidepipes". This design element was not adopted into series production.

The L version was the street model. In addition, a lighter and stronger racing version was planned, the Grifo A3 / C (Competizione). This model started in the Le Mans 24-hour race in 1964 . The Belgian Pierre Noblet and the Swiss Edgar Berney drove the car to 14th place in the overall standings and to victory in the class for prototypes over 5 liters. However, Iso Rivolta did not pursue the racing concept any further. After a falling out between CEO Rivolta and Bizzarrini, the A3 / C was built by Bizzarrini on its own and sold under the name Bizzarrini GT 5300 Strada (as a street version) and Corsa (an even sportier competition version with a plastic body).

The Iso Grifo A3 / L models

Series production of the Grifo began in 1965 and would last until 1974. During this time there was a facelift: in 1970 Rivolta changed the front end by introducing pop-up headlights in the style of Iso Lele , which half covered the front headlights when idle. Apart from these minor external changes, Iso Rivolta always offered new engines with different performances over the years. The performance data given at the time (listed below) were all values ​​according to the SAE standard; the DIN values ​​are about 30% lower.

The basic model

The basic model was initially called Iso Grifo Lusso ; later it was given the additional designation IR 8. Over the years it was offered with various American engines between 5.4 liters and 5.8 liters displacement:

• Between 1965 and 1972 the standard engine was a 5.4 liter eight-cylinder from Chevrolet (Chevrolet Turbofire), which was supposed to produce between 300 and 395 hp through various tuning measures. The German trade journal Auto Motor und Sport examined an Iso Grifo 350 in 1967. In the test, the vehicle reached a top speed of 247 km / h and reached 100 km / h in just 6.4 seconds.

• Between 1970 and 1972 there was also a 5.7 liter version of the Chevrolet Turbofire with outputs between 300 and 365 hp.

• During 1972, Iso switched to Ford engines. The reason for this may have been disagreements with General Motors over the payment for the Chevrolet engines. The previous variety of engines was now history; For the Grifo there was only a 5.8 liter eight-cylinder from Ford (Cobrajet) with 325 hp between 1972 and 1974. The Borg-Warner automatic was replaced by a Cruise-O-Matic from Ford in the same year.

Grifo 7 Litri and Grifo Can Am

Iso Grifo Can Am with the "Penthouse" scoop on the hood and half the sleeping eyes of the Series II

In addition to these basic models, Iso offered a significantly sportier version of the Grifo between 1968 and 1972. In each case, significantly larger engines from General Motors were used, which were more powerful but also heavier and required some changes to the body, chassis and chassis. The era of the great Grifo ended in 1972 when Iso changed its engine supplier: The big block engines from Ford, which were used in the AC  428, for example , did not find their way into the Grifo.

From 1968 to 1970, in addition to the basic model, the Iso Grifo 7 Litri , a particularly sporty version of the Grifo with a significantly larger engine. A 7.0 liter version of the turbofire engine (turbo jet) with 406 hp was used. The large engine ensured outstanding performance. Iso Rivolta stated a top speed of 300 km / h. This value is likely to be too high; Depending on the ratio of the rear axle, a maximum of 275 km / h was realistic. Of course, this was still a value that brought the Grifo into the performance ranges of Ferrari and Lamborghini . The huge engine did not fit under the standard bonnet of the Grifo, so a sweeping scoop - called "penthouse" in the factory jargon - had to be installed, which was detrimental to the line of the car. The 7 Litri were of course very problematic from a thermal point of view in view of inadequate heat dissipation, even though Iso had swapped the standard oil pan of the Chevrolet Turbo-Jet for an enlarged aluminum version with additional cooling fins. However, when driving fast, the engine and cooling water became very hot; there were repeated engine bursts. The German importer Auto Becker in Düsseldorf had temporarily reserved a department in its workshop that dealt with the rapid replacement of the engines of the Grifo 7 Litri.

• The successor to the 7 Litri was the Grifo Can Am. It was offered between 1970 and 1972 and was now powered by a 7.4 liter version of the Turbofire engine. Here, too, the maximum power was specified as 406 hp. Like the 7 Litri, the Can Am had a “penthouse” on the bonnet.

Body styles

• The Iso Grifo was mostly sold as a closed two-seater coupe with a hatchback body. Several vehicles had a steel sliding roof at the customer's request, some were also equipped with a folding sliding roof.

• Between 1966 and 1970, the Milan-based body manufacturer Pavesi produced 17 Grifo with a Targa body. The vehicle remained unchanged with the exception of the removable roof section (between the window frame and the roll bar).

• In January 1964, before series production began, Bertone presented a Spyder based on the Iso Grifo. Apart from the roof section, the vehicle corresponded to the later coupé except for a few details, in particular the front section was already at production level. The very elegant vehicle was not developed for series production; it stayed with a single piece that still exists today.

The production numbers

Between 1965 and 1974 a total of 412 Iso Grifos were produced, 17 of them as Targa. Seventy copies of the 7-liter version were produced, twenty of the Cam-Am version. Of the late Grifo with Ford engines, there were about 25 copies.

Technical specifications

Iso Grifo	GL 300	GL 350	7 Litri (GL 400)	Can-Am	Grifo 1971
Engine:	8-cylinder V-engine (four-stroke), fork angle 90 °
Displacement:	5354 cm³		6998 cc	7443 cc	5766 cc
Bore × stroke:	101.6 x 82.5 mm		108 x 95.5 mm	108 x 101.6 mm	101.7 x 88.9 mm
Performance at 1 / min:	224 kW (304 SAE PS) at 5000	260 kW (355 SAE PS) at 5800	294 kW (400 SAE PS) at 5400	290 kW (395 SAE PS) at 4800	243 kW (330 SAE PS) at 5800
Max. Torque at 1 / min:	488 Nm at 3200	488 Nm at 3600	621 Nm at 3600	677 Nm at 3400	473 Nm at 3800
Compression:	10.5: 1	11.0: 1	10.2: 1	10.25: 1	8.6: 1
Mixture preparation:	1 quadruple carburetor		3 double carburetors	1 quadruple carburetor
Valve control:	OHV , chain
Cooling:	Water cooling
Transmission:	4- or 5-speed gearbox aW GM three-speed automatic rear-wheel drive			GM three-speed automatic rear-wheel drive	5-speed gearbox aW Ford three-speed automatic rear-wheel drive
Front suspension:	Wishbones, coil springs
Rear suspension:	DeDion axle, longitudinal thrust struts, Watt linkage, coil springs
Brakes:	Disc brakes all around, servo
Steering:	Recirculating ball steering, servo-assisted
Body:	Sheet steel, semi-self-supporting, on a platform frame
Track width front / rear:	1410/1410 mm	1440/1440 mm
Wheelbase:	2500 mm
Dimensions:	4430 × 1770 × 1200 mm			4600 × 1800 × 1230 mm
Empty weight:	1430 kg		1510 kg	1610 kg	1590 kg
Top speed:	230 km / h	250 km / h	300 km / h	290 km / h	255 km / h
0-100 km / h:	8 s	7 s	6 s	n / A
Consumption (liters / 100 kilometers):	19 p	21 p	25 p	22 p	18 p
Price (DM):	55,430 (1966)		66,211 (1972)	67,115 (1971)	57,664 (1973)

The Iso Grifo A3 / C

→ Main article : Bizzarrini GT 5300

Iso Grifo GT 5300 Corsa

The Iso A3 / C (for Competizione) is a version of the Grifo designed for racing. Its conception goes back to Giotto Bizzarrini, who was of the opinion that the sale of a road vehicle could be promoted by a competitive version that was successful in racing. About thirty copies of it were produced by Bizzarrini in Livorno by 1965 and at least some of them were marketed under the name Iso and reported at racing events. After Renzo Rivolta and Giotto Bizzarrini split up in a dispute in the summer of 1965, Bizzarrini continued production of the sports car without any major technical or formal changes in its own name. The car was then offered under the designation Bizzarrini GT 5300 until 1968 .

The car

The Iso A3 / C, developed by Giotto Bizzarrini in 1963, had an independent body, but a chassis and drive technology similar to the A3 / L.

The design of the sports car body is usually attributed to Giorgio Giugiaro and thus Bertone, while other sources attribute the design to Giotto Bizzarrini himself and to his colleague Piero Vanni. The body was made of aluminum; it was manufactured by Piero Drogo's Carrozzeria Sports Cars in Modena until 1965 . An exception was the vehicle built in March 1965 with the chassis number B 0222, which was given a plastic body to reduce weight.

As in the case of the A3 / L, the engine of the A3 / C came from the Chevrolet Corvette, but had been redesigned in detail. The performance was specified in the basic version with about 365 hp; Through further work, including the installation of four double carburetors of the type Weber 42 DCOE, the output could be increased to 400 to 405 HP, according to other sources even to 420 HP.

A special feature of the A3 / C was the location of the engine. In an effort to position the weight as centrally as possible in the center of the vehicle, Bizzarrini positioned the heavy American engine far behind the front axle, thereby realizing a front- mid-engine position. It meant that parts of the engine - including the ignition distributor - were only accessible via the passenger compartment. They could be reached through a hatch in the dashboard.

While Renzo Rivolta had the street version Iso A3 / L manufactured by Bertone, the A3 / L was built by Bizzarrini in Livorno. It is not clear how many Iso A3 / C were produced before the separation of Rivolta and Bizzarrini. The details in the literature are very inconsistent; sometimes there is talk of 22 completed cars, sometimes of thirty.

Races

The racing history of the A3 / C, although on closer inspection it was an Iso Rivolta model, is closely linked to Giotto Bizzarrini , his company Prototipi Bizzarrini and the Bizzarrini GT 5300. Bizzarrini was responsible for the racing of the A3 / C right from the start and increasingly deviated from Renzo Rivolta through motorsport.

Even before the A3 / L “Grifo” was ready for series production, the sports version A3 / C competed in the first international competitions. According to an agreement with Renzo Rivolta, who largely financed the racing, the cars were mostly referred to as Iso A3 / C until the summer of 1965. When the cars were first used, they were reported by private drivers; From the summer of 1964, the reports were then mostly made by Giotto Bizzarrini , Bizzarrini Automobili or Iso Bizzarrini Prototipi.

1964

The first race in which an Iso A3 / C took part was the Sebring 12-hour race in 1964 . The drivers were the Americans William McLaughlin , Enus Wilson and Ed Hugus . The team fielded the A3 / C with the chassis number B 0202 and, after starting the race from 29th place, saw the checkered flag as 39th.

The newly built A3 / C with the chassis number B 0207 achieved a particularly prestigious success in the spring of 1964 at the Le Mans 24-hour race . Reported by Bizzarrini's French agency, Société Sonauto , headed by Auguste Veuillet , the Belgian Pierre Noblet and the Swiss Edgar Berney finished 14th overall and won the unlimited prototype class. In the 12-hour race in Reims , which took place six weeks later , the B 0207 did not hold out; Noblet and Berney had to retire at halftime with engine failure. In the course of the year a few more appearances in European mountain and endurance races followed, most of which were contested with the B 0207 by Noblet and Berney, while the B 0202 was used with some success at American events.

1965

Giotto Bizzarrini and Renzo Rivolta hoped to achieve further successes in the endurance races of 1965. For the new season, Bizzarrini built two new vehicles (chassis numbers B 0210 and B 0214), which essentially corresponded to the previous year's models. However, both vehicles were already destroyed during their first use, the 12-hour race in Sebring, when Silvio Moser (B 0210) and Mike Gammino (B 0214) each after a brake failure with their cars against a wall or a Bridge crashed.

The B 0207, which had already been used in the previous year, therefore had to be registered again for the following races; Bizzarrini also built his first car with a plastic body (chassis number B 0222).

In April 1965, Pierre Noblet and Mario Casoni achieved a particular success when they finished fifth overall in the Monza 1000-kilometer race with the old B 0207 , leaving all Ferrari 250 GTO models behind. Antonio Finiguerra and Régis Fraissant in the new B 0222 finished 13th.

Bizzarrini's main focus in 1965 was again on the Le Mans 24-hour race. Initially, Bizzarrini had planned to report three A3 / C vehicles; Ultimately, however, it was only possible to use one vehicle - the B 0222 with a plastic body. Giotto Bizzarrini personally transported the car from Livorno to Le Mans . In the race, the car registered by Iso Bizzarrini Prototipi was driven by Jean de Mortemart and Régis Fraissinet . They crossed the finish line ninth overall and, like last year, achieved class victory.

In the following 12-hour race in Reims, Iso Grifo Prototipi reported two Iso A3 / Cs; both cars retired due to technical defects. A last factory assignment took place in the 200-mile race in Zeltweg , in which Chris Amon finished fourth with the B 0222. From the following year, Bizzarrini organized the races independently. The vehicles reported were now called Bizzarrini GT Strada 5300 and GT Corsa 5300. However, their use soon faded into the background, as Bizzarrini increasingly preferred its new model, the P 538S .

The Iso Grifo 90

The Iso Grifo 90

Rear section of the Grifo 90

In 1991 Piero Rivolta, the son of the company's founder Renzo Rivolta, presented a new vehicle called Iso Grifo 90 . It was a prototype developed by Dallara in Italy , with which Rivolta wanted to test the public's interest in reviving the Iso brand. Unlike most other super sports cars of the time, such as the Ferrari Testarossa or the Lamborghini Diablo , Piero Rivolta again used a classic front-engine design for a new car, which was intended to evoke memories of the concept of the earlier Iso Grifo. The choice of drive technology also corresponded to this approach: like the classic Grifo, the Grifo 90 also used an engine from the Chevrolet Corvette , in this case the most powerful unit from the Corvette ZR-1. The 5.7 liter engine was supposed to produce 440 hp, which was transferred to the rear axle via a six-speed gearbox. The body was designed by Marcello Gandini ; it was made of plastic. The drag coefficient was given as 0.31, the top speed with 299 km / h.

In 1991, a single, yellow-painted prototype was created, which was subsequently shown at various exhibitions. Allegedly Piero Rivolta planned to start series production in 1993. Nothing came of that. The car was not developed for series production; no other vehicle was built. Perhaps one of the reasons for this was the proposed purchase price, which was £ 100,000 and which limited public interest.

literature

• Winston Scott Goodfellow: Iso Rivolta, The Man, The Machines. Motorbooks International 2001. ISBN 88-7911-268-6 .
• auto models , various issues
• Automobil Revue , various catalog editions
• Oldtimer Markt 11/1995: "Mythical Animal" Development history of the Iso Grifo.
• Motor Klassik 12/1989: "Paul's Dream"; Report on the Iso Grifo 7 Litri.
• Richard Heseltine: One Vision . Driving report and model history of the Bizzarrini GT 5300 Strada in: Classic and Sports Car, September 2004 issue.
• Frank Oleski, Hartmut Lehbrink: Series sports cars . Cologne (Könemann) 1993. ISBN 3-89508-000-4 .
• Michael Riedner: Show-Biz . Presentation and driving report Bizzarrini GT Corsa 5300 from 1965. In: Motor Klassik, issue 3/1989.

Web links

Commons : Iso Grifo  - collection of images, videos and audio files

• IsoRegister.de interest group "7 Litri" for Iso Grifo, Rivolta, Lele etc.

Individual evidence

1. ↑ Illustration of the Rondine
2. ↑ Motor Klassik 12/1989.
3. ↑ car catalog No. 15 (1971/72)
4. ↑ for example Bachelor, Robson, Poole: Das große Buch der Sportwagen, p. 84. Likewise Kevin Brazendale: Enzyklopädie Automobil, 1st edition Augsburg (Bechtermünz), ISBN 3-8289-5384-0 , p. 89.
5. ↑ Heseltine: One Vision. Classic & Sports Car 9/2004
6. ↑ In contrast, the almost identical bodies of the Bizzarrini GT 5300, which were produced from 1965 onwards, were manufactured at the small Modeneser body factory BBM; The boat manufacturer Vincenzo Catarsi also built individual plastic bodies. See Heseltine: One Vision. Classic & Sports Car 9/2004.
7. ^ Riedner: Show-Biz. In: Motor Klassik 3/1989, p. 132. After Bizzarrini was responsible for the production of the GT 5300 himself from the summer of 1965, a few more plastic bodies were created that were manufactured by the Italian boat builder Vincenzo Catarsi. The scope of production is controversial; the information ranges from four to nine Bizzarrini specimens.
8. ^ Riedner: Show-Biz, Motor Klassik 3/1989, p. 129.
9. ↑ for example Oleski, Lehbrink: Seriensportwagen, p. 242.
10. ↑ See model history at www.qv500.com ( Memento from March 7, 2005 in the Internet Archive )
11. ↑ An American enthusiast built a new car from the remains of the accident vehicles, cf. Racing chronicle of the A3 / C on the website www.qv500.com ( Memento from March 7, 2005 in the Internet Archive )