Holden Gemini TE
Reviewed by Unique Cars and Parts
Our Rating: 1
After 4 years and 3 model revisions, in 1979 GMH
finally gave the Gemini
a complete makeover, which included a revised engine and alteration to virtually every body panel. The Gemini had now spanned the chasm between the traditional large HZ Holden HZ to the new smaller VB Commodore
, and the styling changes reflected Holden's new visual identity, with the TE looking very much the little brother to the VB
The TE Gemini had quite a few fundamental changes made to it. Though it was between 10 and 12 kilograms heavier than the old TD
model, and its engine delivered slightly less power and torque, performance was improved by 3.4% with a half second improvement in zero to 100 km/h times.
On the outside the TE was between 84mm and 101mm longer than the TD thanks chiefly to the shovel nosed front and new rolled section bumpers. Both front and rear sheet metal were redesigned together with a new grille, lights front and rear, plus mouldings and badges.
Unfortunately the attractive two-door coupe was discontinued, and the SL/E became known as the SL/X. The SL/X had a specification that better suited its place in the market at a better price. Between the SL/X and the base model there was the SL which came with AM push button radio, heated rear window, cigarette lighter and clock as well as exterior trim bits.
Less Power - Better Economy
Under the skin the engine was improved economy-wise by a claimed 10% with redesigned combustion characteristics, carburetion and ignition. Changes to the Isuzu
1.6 litre power plant included a new cylinder head
and different distributor and carburettor settings which in effect reduced performance but increased fuel economy - which was after all one of the main selling points of the car. There was a new fuel pump too to prevent cavitation in hot weather. Power dropped to 50kW and 110Nm.
Early model TDs with RTS were well known for their rather harsh rough road characteristics, although later versions were modified and improved. All of the suspension improvements were incorporated in the TE including-new front suspension
bushes, together with shock absorber valving to take advantage. The rear sway bar was increased in diameter from 13mm to 15mm, thus cutting down understeer.
As with each new model from GMH
, the noise, vibration and harshness package was been uprated too. Gearbox
ratios were raised for better economy, but the 3.9 diff ratio was retained. Seating changes included increased back angle range on the reclining mechanism at the front, and the SL/X model had adjustable head restraints at the front together with integral head restraints for the rear seats. These were in addition to the standard reclining seats and loop pile carpet. The SL/X was fitted with a stereo cassette player, laminated windshield, cloth seat inserts and the head restraints already mentioned.
Other changes included a better quality interior trim and suspension modifications bestowing the TE with a more compliant ride. Combined with some changes to the sound-proofing, the TE Gemini's cabin was a much better place to be over the previous models. All cars were powered by the same 1600cc Isuzu
engine, and were fitted with steel belted radial tyres. There were three transmissions
available. Standard was the four speed manual. The five speed with overdrive top had otherwise the same ratios. Finally there was the three speed automatic.
saw the introduction of the SLX diesel sedan, a great and reliable car, but Australians did not warm to the idea of a diesel in such a small car that already offered good fuel consumption in petrol form (continue reading below for more information on the diesel). Worse still was the competition from the Blue Oval, Ford now taking the fight right up to the Gemini
with the release of the KA Laser
. It seemed Australia's love affair with the Gemini
was fast coming to an end. The General countered with the release of the Sandpiper II Special Edition, however this failed to sway those besotted with the far more modern looks of the Ford Laser. The last of the TE's rolled off the production line in 1982
when the TF model was introduced.
TE Gemini Diesel
It seemed the General was aware that the future of the diesel engine had a bright future in Australia long before many others. And their first oil-burner appeared in 1981, in the guise of a Gemini SL/X. As a total package we doubt it was ever described as a world shaking contribution to design in the eighties. In its mechanical make-up, however, it illustrated how close the Japanese were to emulating their European competition. In fact, GMH made no secret that its Isuzu partners had studied Volkswagen diesel technological expertise when they laid down the guidelines for their small high speed unit.
The Isuzu engine
was introduced in Japan during 1980
, immediately gaining a secure following in that country, orientated as it was to oil engines for many applications. The Isuzu Diesel was an iron headed iron alloy blocked unit with a belt driven overhead camshaft. VW's effort had an alloy head and a cast iron block, so it seems the Isuzu designers did not follow the VW design too closely. Isuzu chose an 1817cc capacity for its 84mm bore, 82 mm stroke design, which, although generally conventional, nevertheless managed to break new ground in detail. A world first in a small high speed unit of this type were the oil spray cooled pistons. The lubricant was introduced at the base of each cylinder and sprayed up into the piston. This, added to the auto-thematic design of the components, restricted the amount of expansion of the piston. In turn that made possible the use of far smaller piston to cylinder wall clearances than were possible in most diesels of this era.
Because of the immense heat generated in the compression ignition process by dint of very high compression ratios, exaggerated clearances were normally needed. These would often result in the typical rattling noises that many still associate with diesel engines - especially when cold, as well as contributing to erratic cold running. Isuzu's design went a long way towards eradicating unacceptable noise and vibration at source by these means. Like the Volkswagen design, Isuzu's engine used a Ricardo Comet Mk 5 pre-chamber cylinder head
design. This was especially effective in small capacity diesels when it came to reducing noise. It had other advantages however, in terms of driveability. In particular it permitted far better torque at low engine speeds, while reducing the level of exhaust smoke that often accompanied low speed torque. This was achieved by using a far greater percentage of the incoming air during the combustion process. Most systems from this era were capable of utilising only between 80 and 85% of the incoming air. The Ricardo Comet MK 5 went as high as 94%.
Torque has always been a diesel engine's strongpoint. The 1800 cc Isuzu unit achieved 105 Nm at just 2000 rpm, and it would pull willingly from 1500 rpm without trouble. Power output was 40 kW at 5000 rpm which, as might be expected, was appreciably more than the 1500cc Volkswagen unit's 37 kW at the same engine speed. The VW diesel gave 82 Nm torque at 3000 rpm, demonstrating that Isuzu really had done its homework. There are very high forces acting within a diesel engine, which makes it difficult to equal the smoothness of a petrol engine.
They have come a long way these days, to be just about on par, but wind the clock back to the early 1980s and it seemed impossible for a diesel to get anywhere near the petrol equivalent. The Isusu unit did get closer than you would have imagined, however, given the attention to detail in all respects that the designers gave. For example, the Gemini's design included such features as a rubber mounted crankshaft pulley for the drive belt to the overhead camshaft, and a flexible bend in the exhaust downpipe. The latter prevented the transmission of boom and vibration from the front of the car to the rear.
The engine and transmission mountings, together with the engine damper, were all carefully placed to further reduce unwanted vibrations. Engine ancillaries were selected on this basis, as well as in the interests of maximum performance. A thermal cooling fan operated through a viscous clutch at the speed necessary for cooling under any particular conditions. The injector pump was of the Bosch VE type, being a single plunger unit which was self priming and self lubricating by means of the fuel oil passing through it. It was quieter in operation, lighter and more compact for small passenger car application. Diesel engine induction systems produce very little vacuum in comparison with petrol engines, so such vacuum as was necessary for the brake servo was supplied by a pump driven in conjunction with the alternator.
Quick Start and Silent Idle
Early 1980s cars fitted with diesels required plenty of messing about when starting from cold. These days most of the hassles have been eliminated. In the case of the Gemini it was a simple matter of switching on, waiting around 3 seconds for the glow plug indicator light to go out, and then turning the key on fully. The waiting period was far shorter than the time taken for a driver to fasten his seat belt - so it was not too much of a hassle. Furthermore, the unit was designed so that the glow plug would stay in operation for up to three minutes when the engine was running initially at under 15 km/h. This feature greatly assisted in reducing noise when the unit was cold, as well as enhancing performance. Isuzu called its start up system "Quick start and silent idle".
Although it might appear that the diesel engine was just a simple option available with the Gemini SL/X, in fact it necessitated a great deal of fundamental change to the car's mechanical features. Because of low speed torque it was possible to use a 3.583:1 final drive ratio rather than the 3.9:1 used in the petrol version. Furthermore, although the first four ratios of the five speed gearbox were the same as in the petrol car, fifth went up to .782 from the original .860. Overdrive could be used effectively during open highway cruising, but often proved a touch too high for regular use in city going. The normal lower four gears were better suited to stop start and low speed conditions, helping to retain driveability, even if at some slight expense in fuel economy.
As well as the additional weight implicit in the diesel engine itself, there was extra mass in the 62 amp/hour battery fitted in order to power the higher capacity starter-motor. The starter-motor had a higher armature speed than before and featured 3:1 reduction gearing. This allowed a much lighter component for the necessary output. All-up the engine
weighed 172 kgs, not including the battery, so the engineers had a challenge if they wanted the Diesel TE to offer the same taught handling with which the Geimini
was, by then, world renowned. The answer was of course in suspension
and damper rates were optimised to brings things back to square one, and although the car tended to have a slight nose down attitude when at a standstill, handling
, road holding and steering
were as good as, if not better than in the petrol powered Geimini
Diesel Gemini Performance
were considered more than capable of coping in view of the slightly reduced performance capabilities. Comparative tests conducted by GMH claimed that, at 6.7 seconds from rest to 60 km/h, the diesel was .7 of a second slower than its petrol counterpart. In the zero to 100 km/h area there was a 2.3 second advantage to the spark ignition unit. Maximum speed in the diesel was 139 km/h compared with 146 km/h. As owners with tell you today, but something a little less known in 1981, was that a diesel engine was not a magic formula for ultimate fuel economy. It was possible to achieve dreadful results unless some knowledge of correct driving techniques were known, and put into practice. In general however, by direct comparison the diesel could attain somewhere between a 17% and 30% improvement.
At the outset the diesel Gemini was available only in the SL/X equipment level, and the first 200 were all finished in a then new shade of green with no other color options available. The reasoning behind the single equipment level was due to the need to maintain local content levels in this basically CKD car. It was the SL Gemini that was always proving the most popular, however this model had less local content than the SL/X, so Holden needed to move more of the upmarket model in order to stay within the 85% limits. Again for the sake of local content, the diesel SL/X featured steel wheels of local manufacture rather than the petrol version's fully imported cast alloy wheels. Nevertheless, plastic wheel trims made them fairly hard to pick other than at a close quarters.
Once the motoring journalists had determined the diesel version handled as well as the petrol version, they seat about determining the fuel consumption - as that was pretty much the sole reason to opt for one. Most managed a best 6.5 litres/100 kms, and always under 7 litres/100 kms around town even in the heaviest of traffic. This compared favourably with the petrol car's 9.55 litres/100 kms. On the open highway the diesel's consumption would drop below 6 litres/100 kms, while the petrol car was lucky (very lucky) to get as low as 7.5 litres/100 kms. So all up, the Gemini diesel was a great little package - the only problem was that the Gemini design, by 1981, was getting long in the tooth and as we mentioned earlier in this article, the competition was biting at its heels.