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Gardner does it again

27th March 1982, Page 18
27th March 1982
Page 18
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Page 18, 27th March 1982 — Gardner does it again
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The new Gardner engine was every bit as good as we've all come to expect from this consistently reliable firm. Tim Blakemore discovered its traditional virtues on the Scottish test route

THIS WEEK'S road test and operational trial is rather special. What distinguishes it is that the tractive unit has a straight-eight engine — the only eight-cylinder, in-line automotive diesel engine in production in Europe. And the name that can be read seven times (the fuel lift pump is bolted to number two) on the engine's cylinder head sideplates? It's Gardner, of course.

For many operators, that name has come to be synonymous with unsurpassed reliability and durability combined with outstanding fuel economy. In short, lower running costs than with any competitive engine. For the yet-to-be-convinced, the Gardner name has meant only a hefty premium on the price lists of those manufacturers offering it as an optional engine, and discouraging replies such as "You'll have to take your place in the queue and it might be a year or two", to any inquiries about the engine's availability.

But L. Gardner and Sons Ltd is no less aware of the drastically changed commercial vehicle market in this country than any other manufacturer and the situation now is very different from that of two or three years ago. A. Gardner customer will certainly not be kept waiting so long nowadays and the price premium is much less daunting than it used to be. In the Seddon Atkinson 401 tractive unit range, the 6LXCT powered model is actually the lowest priced one available, with a retail price of £100 less than Cummins 250 Turbo or Rolls-Royce 265L engined units.

On a horsepower for horsepower basis, it is fairer to compare these Rolls and Cummins engine prices with the 8LXC. There is still not a lot to choose between them, with the installed price of the eight-cylinder engine being £650 more than that of its six-cylinder rivals.

The last two years have also seen a number of technical changes in the hardware that emerges from Gardner's Barton Hall Engine Works at Manchester. The most momentous of these changes was the first appearance of a turbocharged Gardner engine — the 6LXCT — in the summer of last year. It is expected that a turbocharged eight will be in production before the end of this year, perhaps making its public debut at the NEC Motor Show. It was at the last Birmingham Show, in 1980 (when, coincidentally, the 401 was unveiled) that we first saw the 8LXC — a development of the legendary 8LXB.

The most significant change on the new engine was an increase in governed speed from 1,850rpm to 1,920rpm. A modest increase in maximum power and torque, but enough to keep the engine in line with its competitors. Modifications to the cylinder heads, block, pistons, connecting rods and exhaust manifold also helped produc this improvement. Net installe maximum power and torque fc the 8LXB used to be 18414 (247bhp) and 961 Nm (709Ib ft).

At a time when virtually a other engine manufacturer were de-speeding their product to improve fuel economy, th fact that Gardner could push ui maximum speed and still clain outstandingly good specific fuel consumption provided strono evidence of how advanced ail 8LXB was in its day. Gardner': specific fuel-consumption curvo for the 8LXC reaches a minimun of 202g/kWh (0.3325 lb/bhph) a a speed of 1,400rpm but doe: not rise above 2 0 5g/kWl

(0.337Ib/bhph) between 1,000 and 1,920rprn. In other words, it is about as close to a straight line as "damn it" is to swearing.

This engine's minimum full load sfc is not as good as the unrivalled low reached by the 6LXCT and it does not quite match the 1 9 8 g/kWh (0.325Ib/bhph) claimed by Mercedes-Benz for its naturally aspirated vee eight OM 422 111 (used in the 1625). But because the 8LXC's sfc curve hardly curves at all it should mean that grade-A on-the-road fuel economy is possible in all kinds of operating conditions (and, moreover, without the kind of driver discipline involving a featherlight right foot and close scrutiny of the tachometer, demanded by many other modern engines).

Grade-A fuel economy is precisely what this Gardnerpowered Seddon Atkinson 401 achieved over CM's Scottish route. Indeed, it came within an ace (0.98 gallons to be precise) of displacing the Mercedes-Benz 1625 as the most economical user of fuel at 32.5 tonnes with a van semi-trailer.

Operational trial results should never be considered in isolation: so many factors can influence the final figures, though of course we keep the "variables" to a minimum. In this case the weather undoubtedly played a part. When we left MIRA on the first day of the test the south-westerly wind was blowing at a moderate speed of 20 —.30mph but there were reports of 60mph winds in the Glasgow area. By the time we reached the Forth Bridge on the second day, the wind speed had certainly increased, to the extent that some drivers of highsided, unladen vehicles were being warned not to cross the Forth. One such vehicle, an ERF coupled to an unstable singleaxle van semi-trailer, was only allowed to do so after we agreed to escort it, that is, stay in the outside lane on its windward side all the way over the bridge. This kind of manoeuvre does nothing to aid fuel economy.

More handicaps for the 401 were provided by two conscientious police officers, one patrolling the M6 and one the A74, who were curious as to why a new vehicle, painted in its operator's smart livery and obviously laden, should be running on trade plates. Stopping to answer their questions took only a couple of minutes in each case, and the time could be allowed for, but without a fuel flowmeter fitted it was not possible to say exactly what the inevitable fuel consumption penalty was.

However, much more irksome was the encounter we had (or rather the vehicle had) during the test with an agent from the other side of the law. Thanks partly to the usual inefficiency at Forton service area, which we finally decided to quit without filling up, we were behind schedule on the first day of the test and arrived at Gretna after the filling station had closed.

The fill-up the following morning indicated that between MIRA and Gretna the 401 had returned only just over 6.5mpg — an incredibly poor result for this vehicle. It seemed clear that a syphoner had been at work at the unlocked fuel tank during the night, and a re-run over the same section more or less confirmed this. The true recorded consumption was 7.61 mpg.

Lightness is a virtue shared by 401 tractive units and Gardner engines. Consequently, when the two are brought together, kerb weight is sure to be very low. With its 80 gallon fuel-tank full, but without a spare wheel fitted, Stamper's 401 weighed in at 6,439kg (6ton 6cwt 3qr) on MIRA's weighbridge. That is an im

pressively low kerb weight for a sleeper cab tractive-unit, and is one that some non-sleepers cannot better.

Weight has been saved on the 401 chassis cab by extensive use on smc (sheet moulding compound); chassis frame refinements such as the new crossmembers; and a lighter suspension, steering box and fuel tank. The Gardner engine is inherently light because of its aluminium alloy crankcase and numerous other aluminium parts.

However, despite this the 8LXC is not a quiet engine. Noise levels in this cab were noticeably higher than in the two other 401s so far tested by CM — one Rolls 290L powered and one with a Cummins E 290. Our noise meter readings confirmed this, giving readings as high as 82dB(A) at a cruising speed of 60mph. The noise is a low frequency "growl", not particularly unplea

sant to my ears but loud enough to force voices to be raised, and these days that is unusual in a premium tractive-unit.

The eight-cylinder Gardner is also an engine that refuses to be hurried; the revs have to be given time to drop when changing up through the gears. Gardner's own specification sheet shows that maximum torque is developed as low as 1,000rpm, whereas Seddon Atkinson's shows it at 1,100rpm. The difference is of academic interest only, for, like its sfc curve, the 8LXC's torque curve is virtually flat. It is only above 1,700rpm that torque begins to fall away slightly.

During our first attempted restart on the 1-in-5 test hill at MIRA, when the engine spei fell way below 1,000rpm it a peered to stall but then seem( to recover, making a chuffir noise and emitting smoke fro the air intake stack. In fact, wh had happened was that the e gine had begun to run bac wards — something whic seems to be a quirk of Gardn engines as well as two-strol diesel engines.

Gardner tells us that no har results from this, provided th the engine is not allowed to rL that way for any length of time. it is, it will suffer bearin damage from lack of oil pressui because the oil pump is ni working.

Summary

In more favourable circur stances this Gardner-powerE 401 might have set a new fuE consumption record around Scottish route but the resuli make it clear that there is ur likely ever to be a significant di ference in on-the-road fuel ecc nomy between this vehicle an the current record holder — th 1625 Mercedes-Benz. Good mp is a lot less dependent on careft driving technique with the 8LX than it is with the vee eight Mei cedes engine, but then the 162 can be a lot more lively whe required than the somewha ponderous 8LXC 401.

A comparison of the result achieved by these two vehicle adds weight to the opinion tha Gardner's lead in the fuel con sumption stakes at thil horsepower has been whittle( away by a number of other en gine manufacturers over recen years. But L. Gardner and Son; Ltd is not standing still. Thi forthcoming turbocharged eigh promises to be a force to br reckoned with.

Tags

People: Tim Blakemore
Locations: Manchester, Glasgow

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