Iso Grifo
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Production period: | 1964 to 1974 |
Class: | sports car |
Body versions: | Coupe |
Engines: | Gasoline 5.4-7.0 litres |
Length: | 4430-4600 mm |
Width: | 1770-1800 mm |
Height: | 1200-1230 mm |
Wheelbase: | 2500 mm |
Curb weight: | 1430-1610 kg |
The Iso Grifo is a sports car built 1964 to 1974 built by the Italian car manufacturer Iso Rivolta.
History
After the four-seater coupe Iso Rivolta IR 300 Iso 1964 presented the conceptually similar, but sporty designed two-seater Iso-Grifo coupe, a Gran Turismo for the wealthier man.
The prototype of the Grifo was shown in late 1963 at the Turin Motor Show under the name A3 / L (Lusso). This line largely corresponded to the later production model; only the front end differed by obliquely mounted headlights and a three-dimensional grille. Between the front wheel arch and the A-pillar there was a striking vent, which was covered with individual chromed struts and revealed the view of an exhaust pipe lying behind it in the style of American "Side Pipes". This design element was not adopted in series production.
Engineer Giotto Bizzarrini, a former Ferrari employee who left the factory of the Commendatore Ferrari in the dispute and opened his own design office in Livorno in 1963, was instrumental in the development of the Grifo. Bizzarrini designed a platform frame with box girders, which was similar to that of the Iso Rivolta IR 300 - except for a shortened wheelbase by twenty centimetres. American V8 engines were intended, and first from the Chevrolet Corvette the derived 5.4-liter V8. Other technical components were also bought in: The steering came from Burman, the limited slip differential from Salisbury, the disc brakes from Dunlop, manual gearboxes with five gears from ZF Friedrichshafen, four-speed gearbox from Mancie or Borg-Warner or a three-speed automatic from Borg-Warner gearbox Warner 4-speed all-synchromesh, gear ratios top 1.0, third 1.51, second 1.92, first 2.54, reverse 3.36; final drive Salisbury Powr-Lok hypoid bevel 3.07:1.The steering Burman recirculating ball type; wheel diameter 15.0 in.; brakes Dunlop discs front and rear, servo vacuum type, dimensions, front 11.75 in. diameter, rear 12 in. diameter; wheels cast alloy ventilated disc with centre-lock hubs, 6 in. wide rim; tyres Pirelli Cintürato HS tubed, 205-15 in.
The design of the coupe contributed, as with the Iso Rivolta IR 300, Bertone; in fact, it was a work by the young Giorgio Giugiaro, whom Bertone had recently appointed as Design Director. Giugiaro drew a low, cat-like hatchback body with gently rounded, tight-cut fenders and clearly recognizable, slightly inclined roll bar. On the low front you could see round twin headlights. The rear end was dominated by a large panorama window, which merged into a trunk attachment, and tapered significantly to the car end. Between the front wheel arches and the A-pillar large vents were provided, which were chromed on some models. The main features of the design go to the Pininfarina Rondine I a show car, the American Tom Tjaarda had designed in 1963 on the technical basis of the Chevrolet Corvette.
The L version was the street model. In addition, a lighter and stronger racing variant was planned, the Grifo A3 / C (Competizione). This model started in 1964 at the 24 Hours of Le Mans. The Belgian Pierre Noblet and the Swiss Edgar Berney drove the car to the 14th place in the overall standings and to victory in the class for prototypes over 5-liter displacement. However, the racing concept was not pursued by Iso Rivolta. After a rift between company president Rivolta and Bizzarrini, the A3 / C was built by Bizzarrini on its own under the name Bizzarrini GT 5300 Strada (as a street version) and Corsa (an even sportier competition version with plastic body) sold.
1965 began the series production of the Grifo, which should last until 1974. In this time, there was a facelift: In 1970, Rivolta changed the front end by folding headlamps were introduced in the style of Iso Lele , which half obscured the headlights at rest. Apart from these minor external changes, Iso Rivolta has always offered new engines with different performances over time.
Main Versions
- A 3L Grifo (1965)
- Grifo GL (1965 - 1970)
- Grifo 7 liters (1968 - 1970)
- Grifo IR8 (1971 - 1974)
- Grifo IR8 Can-Am (1971 - 1974)
The basic model was initially Iso Grifo Lusso; later it received the additional designation IR 8. It was offered over time with various American engines between 5.4 litres and 5.8 litres displacement.The Iso Grifo was mainly sold as a closed two-seat coupe with hatchback body. Several vehicles had a steel sunroof on customer request, some were also equipped with a folding sunroof.Between 1966 and 1970, the Milan body manufacturer Pavesi made 17 Grifo with a Targa body. The vehicle remained unchanged with the exception of the removable roof part (between window frame and roll bar).
Even before the start of mass production Bertone presented in January 1964 before a Spyder based on the Iso Grifo. Apart from the roof section corresponded to the vehicle except for a few details of the later coupe, especially the front end was already at the standard level. The very elegant vehicle was not developed for series production; it remained with a single piece, which still exists today.
Between 1965 and 1972 as a standard engine a 5.4-liter eight-cylinder Chevrolet (Chevrolet Turbofire) was provided, which should afford by different tuning measures between 300 and 395 hp.
- PERFORMANCE
Engine capacity: 326.98 cu in, 5,358.60 cu cm
Fuel consumption: 15.7 m/imp gal, 13.1 m/US gal, 18 1 x 100 km
Max speed:136.7 mph, 220 km/h
max power (SAE): 300 hp at 5,000 rpm
max torque (SAE): 361 1b ft. 49.8 kg m at 3,200 rpm
max engine rpm; 5,200
specific power: 56 hp/l
power-weight ratio: 10.1 lb/hp, 4.6 kg/hp
max speeds: 53.4 mph, 86 km/h in 1st gear; 70.8 mph, 114 km/h in 2nd gear; 90.7 mph, 146 km/h in 3rd gear; 136.7 mph, 220 km/h in 4th gear
Between 1970 and 1972, there was also a 5.7-liter version of the Chevrolet Turbofire with outputs between 300 and 365 hp.
- Grifo GL 365
max power (SAE) 365 hp at 6,200 rpm
max torque (SAE) 361 1b ft, 49.8 kg m at 4,000 rpm
max engine rpm, 6,200
specific power, 68.1 hp/l
fuel consumption 14.9 m/imp gal, 12.4 m/US gal, 19 1x100 km.
max speed (I) 61.5 mph, 99 km/h, (II) 82 mph, 132 km/h, (III) 103.7 mph, 167 km/h,
(IV) 161.5 mph, 260 km/h
During the year 1972, Iso switched to Ford engines. This may have been due to disagreements with General Motors over the payment of Chevrolet engines. The previous engine diversity was now history; for the Grifo there was between 1972 and 1974, only a 5.8-liter eight-cylinder Ford (Cobra jet) with 325 hp. The Borg-Warner automatic was replaced in the same year by a Cruise-O-Matic from Ford.
In addition to these basic models Iso offered between 1968 and 1972 a much sportier version of the Grifo. In each case was used on much larger engines from General Motors, which were more potent, but also heavier and some changes to the body, chassis and chassis required. The era of the big Grifo ended in 1972, when Iso changed its engine supplier: Ford's Big Block engines, used in the AC 428 for example, did not make it into the Grifo.
From 1968 to 1970 was in addition to the basic model of Iso Grifo 7 Litre on offer, a particularly sporty version of the Grifo with a much larger engine. A 7.0-liter version of the Turbofire engine (Turbo-Jet) with 406 hp was used. The big engine provided outstanding performance. Iso Rivolta announced 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. This, too, was still a value that the Grifo in the performance of Ferrari and Lamborghini. The huge engine did not fit under the standard bonnet of the Grifo, so that a sweeping scoop - in the factory had to be installed, which was detrimental to the line of the car. However, the 7 Litre were thermally very problematic in view of poor heat dissipation, although Iso had exchanged the standard oil pan of the Chevrolet Turbo-Jet for an enlarged, provided with additional cooling fins aluminium version. At high speeds, the engine and cooling water heated up a lot; it repeatedly came to the bursting of engines.
- The successor of the 7 Litre was the Grifo Can Am. It was offered between 1970 and 1972 and has now been powered by a 7.4-liter version of the Turbofire engine. Again, the maximum power was specified with 406 hp. The Can Am had as well as the 7 Litre the hood.
Between 1965 and 1974, a total of 412 Iso Grifo was produced, 17 of them as Targa. The 7-Litre version was produced in seventy copies, the Cam-Am version in twenty copies. From the late Grifo with Ford engines there were about 25 copies.
Description
Technical
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Iso Grifo Technical details and specifications (1964-1974)
ENGINE: 326.98 cu in , 5,358.60 cu cm
location front
4 stroke; cylinders: 8, Vee-slanted at 90°
bore and stroke: 4 x 3.25 in, 101.6 x 82.6 mm
engine capacity: 326.98 cu in, 5,358.60 cu cm
compression ratio: 10.5
cylinder block: cast iron
cylinder head: cast iron
crankshaft bearings: 5
valves: 2 per cylinder. overhead, push-rods and rockers, hydraulic tappets Grifo GL without hydraulic tappets
camshafts: 1, at centre of Vee
lubrication: gear pump, full flow filter
carburation: 1 Carter AFB downdraught a-barrel carburettor
Grifo GL 1 Holley downdraught 4-barrel carburettor
fuel feed: mechanical pump and fuel pumps 2 Bendix electric
cooling system: waterEngine: 6,998 c.c
Engine capacity:6,998 c.c.
bore 107.95 mm., stroke 95.5 mm
compression ratio 10.25:1
pushrod valves
Rochester carburetter with air silencer
AC fuel pump
pump water circulation
AC ignition; 12-volt 60-amp./hr. battery
developing 400 b.h.p. at 5,200 r.p.mTRANSMISSION
driving wheels: rear
clutch: single dry plate
gearbox: mechanical; gears: 4 + reverse
synchromesh gears: all
gearbox ratios:2nd 1.920, 3rd 1.510, 4th 1, rev 3.360
gear lever: central
final drive: hypoid bevel
axle ratio: 2.880. Grifo GL 3.070CHASSIS
type integral
front suspension: independent, wishbones, coil springs, anti-roll bar, telescopic dampers
rear suspension: de Dion rigid axle, twin trailing radius arms, transverse linkage bar, coil springs, telescopic dampers.STEERING
recirculating ball
turns of steering wheel lock to lock: 4.50.
turning circle (between walls): 39.4 ft, 12 mBRAKES
disc (front diameter 12 in, 305 mm, rear 11 in, 279 mm), servo
area rubbed by linings: front 268.53 sq in, 1,732 sq cm
area rubbed by linings: rear 243.10 sq in, 1,568 sq cm,
total 511.63 sq in, 3,300 sq cm.ELECTRICAL EQUIPMENT
voltage: 12 V
battery: 60 Ah
generator type: alternator, 500 W
ignition distributor: Delco-Remy
headlamps: 4.DIMENSIONS AND WEIGHT
wheel base: 98.42 in, 2,500 mm
front track: 55.51 in, 1,410 mm
rear track: 55.51 in, 1,410 mm
overall length: 174.41 in, 4,430 mm
overall width: 69.68 in, 1,770 mm
overall height: 47.24 in, 1,200 mm
ground clearance: 4.72 in, 120 mm
dry weight: 3,043 1b, 1,380 kg
distribution of weight: 46.5% front axle, 53.5% rear axleIso Grifo range comparison Technical data
Iso Grifo
GL 300
GL 350
7 Litre (GL 400)
Engine:
8-cylinder V-engine (four-stroke), fork angle 90 °
displacement:
5354 cc
6998 cc
Bore × stroke:
101.6 × 82.5 mm
108 × 95.5 mm
Power at 1 / min:
224 kW
(304 SAE-PS)
at 5000260 kW
(355 SAE-PS)
at 5800294 kW
(400 SAE hp)
at 5400Max. Torque at 1 / min:
488 Nm at 3200
488 Nm at 3600
621 Nm at 3600
Compression:
10.5: 1
11.0: 1
10.2: 1
Fuel supply:
1 quad carburettor
3 double carburettors
Valve control:
OHV, chain
Cooling:
water cooling
Transmission:
4- or 5-speed gearbox
aW GM automatic reverse
drive rear-wheel driveFront suspension:
Wishbone, coil springs
Rear suspension:
DeDion axle, longitudinal push rods, Watt linkage, coil springs
brakes:
Disc brakes all around, servo
Steering:
Recirculating ball steering, power-assisted
Body:
Sheet steel, semi-self-supporting, on platform frame
Track front / rear:
1410/1410 mm
1440/1440 mm
Wheelbase:
2500 mm
Dimensions:
4430 × 1770 × 1200 mm
Empty weight:
1430 kg
1510 kg
maximum speed:
230 km / h
250 km / h
300 km / h
0-100 km / h:
8 s
7 s
6 s
Consumption (litres / 100 kilometres):
19 p
21 p
25 p
Iso Grifo
Can-Am
Grifo 1971
Engine:
8-cylinder V-engine (four-stroke), fork angle 90 °
displacement:
7443 cm³
5766 cc
Bore × stroke:
108 × 101.6 mm
101.7 × 88.9 mm
Power at 1 / min:
290 kW
(395 SAE-PS)
at 4800243 kW
(330 SAE-PS)
at 5800Max. Torque at 1 / min:
677 Nm at 3400
473 Nm at 3800
Compression:
10.25: 1
8.6: 1
Fuel supply:
1 quad carburettor
Valve control:
OHV, chain
Cooling:
water cooling
Transmission:
GM three-speed automatic
rear-wheel drive5-speed gearbox
aW Ford three-speed automatic
rear-wheel driveFront suspension:
Wishbone, coil springs
Rear suspension:
DeDion axle, longitudinal push rods, Watt linkage, coil springs
brakes:
Disc brakes all around, servo
Steering:
Recirculating ball steering, power-assisted
Body:
Sheet steel, semi-self-supporting, on platform frame
Track front / rear:
Wheelbase:
2500 mm
Dimensions:
4600 × 1800 × 1230 mm
Empty weight:
1610 kg
1590 kg
maximum speed:
290 km / h
255 km / h
0-100 km / h:
n / A
Consumption (litres / 100 kilometres):
22 p
18 p
© Motor car History
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Iso Grifo Service Guide (1964-1974)
326.98 cu in , 5,358.60 cu cm
Fuel: 98-100 oct petrol
Engine sump oil: 13.90 imp pt, 16.70 US pt, 7.9 1, SAE 20W-40, change every 3,100 miles, 5,000 km
Total lubricating system capacity: 14.96 imp pt, 17.97 US pt. 8.5 1 oil filter AC full-flow, renewable element
Gear-box oil: 2.64 imp pt, 3.17 US pt, 1.5 1, SAE 90, change every 12,400 miles, 20,000 km
Final drive oil: 2.64 imp pt, 3.17 US pt, 1.5 1, SAE 90, change every 12,400 miles,20,000 km
Cooling system capacity: 31.68 imp pt. 38.05 US pt
Greasing: every 3,100 miles, 5,000 km, 10 points
Valve timing: inlet opens 32°30' before tdc and closes 87°30' after bdc, exhaust opens 74°30' before bdc and closes 45°30'after tdc
Grifo GL tappet clearances 0.030 in, 0.75 mm
Normal tyre pressure:front 34 psi, 2.4 atm, rear 37 psi, 2.6 atm.
Tyres: 205 x 15
Fuel tank capacity: 22 imp gal, 26.4 US gal, 100 1.
Carrying capacity: 573 1b, 260 kg© Motor car History