Two Classics: BMW Z8 and Isetta

Interesting | December 21st, 2008 by 4
440190656 vpdkc x2 Two Classics: BMW Z8 and Isetta

The BMW Z8 and the old-timer Isetta are two cars that we don’t get to see very often. If the Z8 could be spotted once …

The BMW Z8 and the old-timer Isetta are two cars that we don’t get to see very often. If the Z8 could be spotted once in a while on the roads, Isetta can only be seen in museums or vintage car shows. The first BMW Isetta appeared in 1955 and it was powered by a BMW one-cylinder, four-stroke, 247 cc motorcycle engine making 13 hp (10 kW). 

The BMW Isetta 250 started to become even more popular and the car was also redesigned to take a modified version of the 250 cc 4-stroke engine from the BMW R25/3 motorcycle and the front suspension was changed. The single-cylinder generated 12 hp (9 kW) at 5800 rpm. The crankcase and cylinder were made of cast iron, the cylinder head of aluminium. However, the head was rotated by 180 degrees compared with the motorcycle engine. The twin-bearing crankshaft was also different in the Isetta power unit, being larger and featuring reinforced bearings.

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The power train from the four-speed gearbox to the two rear wheels was also unusual: fixed to the gearbox output drive was something called a Hardy disc, which was a cardan joint made of rubber. On the other side of it was a cardan shaft, and finally a second Hardy disc, which in turn was located at the entrance to a chain case. A duplex chain running in an oil bath led finally to a rigid shaft, at each end of which were the two rear wheels. Thanks to this elaborate power transfer, the engine-gearbox unit was both free of tension and well soundproofed in its linkage to the rear axle.

Isetta 300, the car featured in the photos taken by our friend Palbay, has seen some improvements from the previous version. The bubble windows were replaced by longer, slidding side windows and BMW had enlarged the single cylinder to a 72 mm bore and 73 mm stroke, which gave a displacement of exactly 298 cc, and at the same time they raised the compression ratio from 6.8 to 7.0:1. In this way the engine now generated 13 hp (10 kW) at 5200 rpm, and the torque rose to 18.4 N·m at 4600 rpm. The maximum speed remained at 85 km/h (53 mph). Isetta 300 was still possible to be driven without a license despite the fact that from 1956 first-time drifvers had to pass the test for Class III if they wanted to drive an automobile.

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Also, according to history books, the 250 cc engine did not qualify for full tax discounts, so BMW moved the Isetta to 300 cc.

Now, let’s talk a bit about the beautiful, rare, head-turning BMW Z8. The high-class roadster made its debut in 2000 and for its three years life span, there were 5,703 units built. The Z8 was the production variant of the 1997 Z07 concept car, which was designed by Henrik Fisker at BMW’s Designworks in Southern California. The Z07 originally was designed as a styling exercise intended to evoke and celebrate the 1956-’59 BMW 507.

BMW Z8

The original Z07 had been designed with production in mind. But due to regulatory  laws and customer feedback some changes were made for the production model. The windshield of the Z8 was extended upward, and a larger front airdam was fitted. Both changes were implemented to provide aerodynamic stability and a reasonably placid cockpit environment. The four spoke steering wheel of the concept car was replaced by a three spoke design. The hardtop was changed from a double-bubble form with a tapering faring to a single dome with a truncated convex backside. The concept’s exotic driver’s side helmet fairing was eliminated to allow easy operation of the power soft top.

 

At $128,000, the Z8 was placed near high-end of BMW’s lineup. The car had an all aluminum chassis and body and used a 4.9 L (4941 cc) 32 valve V8, that developed 400 hp (294 kW) and 500 Nm (363 lb·ft). This engine was built by the BMW M division and was shared with the E39 M5. The engine was located behind the front axle in order to provide the car with 50/50 weight distribution. The factory claimed a 0 to 100 km/h (0 to 62.5 mph) time of 4.7 seconds, but faster times were achieved by professional drivers and car magazines. The usual stop on the top speed was present in the Z8 as well, 155 mph (249 km/h), but several tuners were able to achieve 186 mph (300 km/h) with an unlocked chip.

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I won’t get into many details now, we’ll save those for a full review of the Z8, so I will rather have you take a look at the images that were snapped by Palbay.

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