The Holden straight-six motor is a series of straight-six engine that were produced by General Motors–Holden's in Australia between 1948 and 1986. The initial Grey motor was so dubbed because of the colour of the cylinder block, later motors came in the form of a Red, Blue, Black, and the four-cylinder Starfire engine. These engines were fitted to all Australian designed Holdens of the same years, and the four-cylinder Starfire notably also found its way into the Toyota Corona. The Grey motor is a different engine from the others, while the Red, Blue, Black, and even the Starfire are all inter-related with many common parts and castings.
Grey
The Grey motor, built between 1948 and 1962, earned its name as the engine block was painted grey. This overhead valve engine was first fitted to the Holden 48-215 and mated to a three-speed column change gearbox. A three-speed GM Roto-Hydramatic 240automatic transmission was an option fitted in the latter EK and EJ series. The engine was based on a Buick pre-World War II design, and saw only minor changes throughout its 15-year life. It displaced in its original form as used by the 48-215, and remaining in use until the FC. Holden replaced the FC in 1960 with the FB series, and its engine was bored out to. It developed at 3800 rpm, providing superior performance to the competing four-cylinder Austin, Morris, Vauxhall and Ford of Britain vehicles. The grey motor featured a compression ratio inlet ports for cylinders 1–2, 3–4 and 5–6, two individual exhaust ports for cylinders 1 and 6, and two siamese exhaust ports for cylinders 2–3 and 4–5 in a layout on one side of the head casting. The inlets were fed by a single-barrel Stromberg carburettor in common and fitted with a traditional Kettering ignition by coil and distributor. The electric system was six volts in the 48-215 and FJ. The earliest grey motors were fitted with Delco-Remy accessories, although Lucas and Bosch equivalents throughout the motor’s lifetime replaced these. The very first production grey motor was number 1001, and they continued in a single sequence until July 1956, when the prefix "L" was introduced. The change affected all engines numbered L283373 and above, signifying the 12-volt negative-earth engines as fitted to the all new FE model. The prefix "U" was introduced for motors with the original electricals as fitted to the FJ utility and panel van models, which ended in February and May 1957 respectively. The change was effective from engine U283384. The prefix "B" was introduced and the number sequence reset with the introduction of the displacement engine, and ultimately this was replaced by a "J" prefix for motors fitted to EJ vehicles in 1962.
Superseding the Grey motor, the Red motor was manufactured between 1963 and 1980. This was a completely new engine and in no way a further development of the grey motor. It featured a seven-bearing crankshaft, full flow oil filter and hydraulic valve lifters. Denoted by the cylinder block painted red, the engine made its debut in the Holden EH in capacities of and producing and respectively. This was a power increase of 33 per cent and 53 per cent over the grey motor. Red six-cylinder engines manufactured after October 1964 had the cubic inch capacity of the engine cast in raised numbers on the side of the block behind the generator/alternator location. Red engines manufactured prior to October 1964 had either no numbers cast or the letters "HP" cast. All Red engines manufactured prior to April 1967 had forged steel crankshafts. This includes all 149 and 179 ci engines, and 161 and 186 ci engines manufactured before that date. ;Capacities
The Blue specification debuted in the 1980 VC Commodore. The blue motor was a development of the earlier red engine, and incorporated several improvements. The biggest of these changes was the complete redesign of the cylinder head; this was now a 12 port design with individual ports for each cylinder. The crankshaft for the 3.3-litre engine now had counterweights on each throw, and stronger connecting rods were used. A two-barrel Varajet carburettor was standard, as was a dual outlet exhaust manifold and a Bosch HEI distributor. It was made in 3.3- and 2.85-litre versions.
The Black specification was introduced in the 1984 VK Commodore. The black engine was produced in 3.3-litre form in carbureted versions. The carbureted engine was almost identical to the previous blue engine, the main difference being in the use of computer controlled spark timing taking its timing pick-up from the flywheel area. The ports were slightly wider spaced, meaning the manifolds will not simply interchange. The Bosch-injected version used a long-runner intake manifold and a conventional HEI ignition. It also had slightly different cylinder head intake ports for improved breathing.This engine was painted Red, slightly redder than the earlier "red" motors which looked orange compared to the VK FI motor. In the 1986 VL Commodore, Holden replaced the Australian-made and designed six-cylinder engines with the NissanRB30E and RB20E engines. Pending emission standards and the requirement for unleaded fuel made it difficult to re-engineer the Australian engine.
Applications
1984–1986 Holden Commodore
Starfire
This 1.9-litre powerplant, known as the Starfire engine, was effectively Holden's existing 2.85-litre 173 cu in straight-six with two cylinders removed. Designed and built in Australia to satisfy local content rules, it first appeared in 1978 during the UC Sunbird's production run, replacing the Opel 1.9-litre cam-in-head unit used in LH, LX and earlier UC Torana/Sunbird 4-cylinder models. Peak power output for the Starfire was, with a 17.5 second acceleration time from 0–100 kilometres in the VC Commodore. This variant's performance meant the need to push the engine hard leading to fuel consumption similar to the straight-sixes. Due to this, it was often nicknamed as Misfire or Backfire. This engine was replaced in the Australian market by the Camira's OHC Camtech unit, however, it continued to be used until 1986 in New Zealand, where it was used to power four-cylinder versions of the VK Commodore. This engine was also used by Toyota Australia to meet local parts content regulations for the Corona XT130. Engines installed in Toyotas received some slight differences in the form of a unique camshaft, manifold, and carburettor. Toyota called the engine the "1X" and it had a slightly different power curve: at 4800 rpm and at 2400 rpm.
