Whether they’re cookin’ with gas or diesel, GMC trucks get new power for 1999

DETROIT — New or improved engines highlight the 1999 GMC lineup of light-medium and medium-duty trucks from General Motors, including the only gasoline engine offered for a heavy-duty truck.

General Motors said its class-5 to -8 C-Series conventionals and T-Series tilt-cabs will be available with two new diesels, the Caterpillar 3126B (7.2 litres) and the Isuzu-built Duramax 7800 (7.8 litres, for the TÐSeries only).

The Cat 3126B in-line six provides seven power and 10 torque ratings, from 175 to 300 horsepower and from 420 to 860 pound feet. New electronic features include a parameter lockout fan control; full PTO functions, including shutdown timer, cooling fan activation and vehicle speed limit; progressive shift control; and coolant-temperature based monitoring.

The Duramax 7800 is an in-line six-cylinder 7.8-litre diesel with dry cylinder liners, overhead cam, and four valves per cylinder. It comes with two power ratings: 200 or 230 horses at 2400 rpm, and 441 or 517 pound feet of peak torque at 1500 rpm. The OHC design — almost unique in this power range — helps to reduce emissions and increase fuel economy.

GM will offer a new gas engine: the Vortec 7400 MD V8, for C-Series conventionals, replacing two six- and seven-litre engines. Its two ratings: 210 horsepower at 3750 rpm and 325 pound feet of torque at a very low 1200 rpm, or 270 horses at 3750 and 405 pound feet at 3200 rpm. A design key is the engineÕs all-new electronic throttle control, which allows for engine- or road-speed governing and PTO control. As well, the 270 model can be more easily converted to liquid propane gas (LPG) without needing the optional sodium exhaust valves previously required.

Another part of the GMC story is its market success this year. Based on dealer orders, GM says it has nearly sold out its Janesville, Wis., plantÕs complete production capacity for the 1999 model year, ending next July — despite three capacity increases since 1996 and the plant operating at maximum line rate and maximum overtime.