The introduction in 1986 of the VL Commodore - with its sweet Nissan six - was a bolt from the blue. The engine was simply revelatory for Holden performance.... Not just in the numbers, but also in the refinement and durability of the engine.
The VL Six
"A thoroughly modern, well-sorted 3.0 litre six with good torque, healthy power, willing response and good fuel consumption figures." (Modern Motor, March 1986)
Nineteen eighty-six was a significant year - the introduction in Australia of unleaded petrol. By law, only cars able to run on unleaded fuel could be sold - and this requirement posed a major dilemma for Holden. Their six cylinder engines were technical dinosaurs - even the injected VK 3.3 litre six had only a modest power output and was the result of the constant evolution of a design first sold no less than 23 years previously. To meet the requirements of unleaded petrol, forthcoming emissions legislation, and commercial goals concerning power and fuel economy, Holden desperately needed a clean-sheet design. An engine which could power their mainstream cars for the next decade or more; one that in one fell swoop would overcome the problems that the old pushrod six had now saddled them with.
But there was a major problem - Holden could not afford the design and development process of a new engine; the engine plant alone they conservatively estimated as costing $300 million. The company searched the world for a suitable replacement six-cylinder, looking in the US, Europe, Britain (where they considered the SOHC 3.6 litre Jaguar six!) and Japan. Within the GM family there was nothing; the Opel six-cylinder engine was regarded as a heavy, old design, and the then-new versions of the V6 engines in the USA were said to be not powerful enough. (Interesting, given their later adoption in the next-model VN Commodore!)
Discussions were held with Toyota, but aborted when it was found that the largest six-cylinder they had available had only a 2.8 litre capacity - and couldn't be supplied in sufficient numbers anyway. Holden then settled on Nissan, with the decision made in late 1982 and work starting with the Japanese company in January 1983 (a time about halfway through the VH Commodore's model run). So a Nissan engine had been picked to power the 1986 VL Commodore; the Holden sixes were to be unmourned in their departure.
Design and Development
While at the time of the VL's release it was implied by Holden that they had had a major hand in the development of the Nissan engine, in fact it appears that only one Holden engineer was stationed in Japan. Most likely, Holden's input was confined to specifying appropriate durability testing for Australian conditions and then engineering a good marriage of the engine with the Commodore body. (And of course requesting that 'Holden' be written on the rocker cover!)
The engine was the Nissan RB30E, a SOHC in-line six with a 3-litre capacity. Developed by Nissan from the old L-series sixes, the RB featured cam drive via a toothed belt, a completely new cross-flow head, new intake and exhaust systems, a shorter block, and sophisticated engine management. Nissan's RB series spawned a wide variety of engines, culminating in the twin-turbo Skyline GT-R's RB26DETT. However, the engine in the VL Commodore was at that stage available in Australia only in naturally aspirated form. It was under the bonnet of the VL that Australians first saw the new Nissan six - the engine would only later also be released in the local R31 Skyline.
Bore and stroke of the 3-litre was a slightly oversquare 86mm by 85mm. Hydraulic valve lifters were used in the 12-valve head, which also featured centre-mounted spark plugs and a multiple-runner intake manifold. The forged crankshaft used eight counterweights, while the iron block was trapezoid-shaped with spherical skirts for each cylinder. The compression ratio was 9:1. One area where the new engine was relatively poor in design was in its mass - it actually weighed 11kg more than the 3.3-litre injected version of the old pushrod six. However, in other comparisons with the injected 3.3 it was streets ahead - let alone when the VK's base model carby 3.3 was used as the benchmark.
The RB30E (called in Holden literature just the '3.0E') developed 114kW at 5200 rpm and 247Nm at 3600 rpm. Compared with this, the previous 3.3 in injected form was 7 per cent down in power, although it had 8 per cent more torque. But against the carby 3.3, the new engine had 6 per cent more torque and a massive 33 per cent more power. The latter figures are the more significant - not many of the old 3.3 litres sixes were equipped with the Bosch EFI. But what performance did this spell on the road? Holden's own figures showed that a manual 5-speed VL could do the standing 400 metres in 16.7 seconds, while the previous quickest manual six-pack (the carby engine, because the EFI six could only be bought in auto form, remember) did the 400 metres dash in an agonising 18.1 seconds...
Another new-found aspect of the VL was its gearboxes - they were also direct from Nissan. The automatic transmission was the first Commodore 4-speed auto, while the manual gearbox was also the first time that a 5-speed had been fitted to all trim level manual Commodores. The automatic trans featured a lock-up torque converter and very tall gearing - in fourth, nearly 48 km/h per 1000 rpm was available. Even the manual 'box had gearing aimed at a relaxing high-speed cruise, with 43.4 km/h per 1000 rpm. The six cylinder VLs ran a 3.45 diff ratio, shorter than generally fitted to the previous models.
While the big news was in the drivetrain, the VL model also featured a major styling revision. The nose was lower with homofocal headlights (complete with pop-up covers on the Calais), a new front bumper was fitted, a lip was added to the boot lid, and the interior received a substantial makeover. It was arguably the prettiest interpretation of the Opel V-car shape - though the VL's origins were still unmistakeable and the dashboard dated fast.
The VL six was certainly a sweet engine, but the Turbo performance powerhouse was yet to come....
Next issue: the Ar-Bee Thirty Eeee Teee
The VL Commodore Six - Part 1
The VL Commodore Six - Part 3
The VL Commodore Six - Part 4
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