After years of watching competitors lure customers with high-revving V-6 engines, General Motors has one of its own.
The new engine, a descendant of Cadillac's Northstar V-8, will debut on the 1999 Oldsmobile Intrigue this fall.
The 3.5-liter engine has all the requisite equipment of Japanese competitors: dou-ble-overhead camshafts, four valves per cylinder, aluminum block and heads and more than 200 hp.
General Mo-tors needs this engine, code-named LX5, for various reasons. Oldsmobile is trying to cast itself as an import fighter; the engine will help.
GM also wants an overhead-cam engine to hurdle tougher emissions regulations slated for the next decade. Sources say it will replace the pushrod 3800 series II V-6 on many GM cars in the next five years.
NO GOLD PLATING
Max Freeman, who led the engine development team at GM Powertrain, used this guiding principle: Give GM's customers exactly as much engine technology as they need and can afford.
Before a feature went in, Freeman and his engineers tried to gauge whether it would fit under the hood and whether buyers would appreciate it enough to pay the extra cost.
'We don't want to put a lot of gizmos into the engine unless the customer will perceive that he got something for that technology,' Freeman says.
Variable air intake and valve timing, for instance, were rejected because they 'may cost $100 (per engine), but can you tell the difference if they give you a blindfold test?'
Timing belts were another example. Although quieter than the chains GM uses on all Northstar-based engines, the belts require changing every 60,000 miles at $500 per change.
'In a 150,000-mile life of an engine, you're going to do that twice. That's $1,000 you'll spend that a Northstar or premium V-6 customer isn't going to have to.'
EASIER AND CHEAPER
What did make it into the engine was hardware designed to make ownership easier and cheaper. Low-friction roller valve openers were used for the first time on a Northstar-based engine instead of direct bucket lifters. Engineers estimate this feature alone can save as much as 1 mpg.
Also, an oil-life monitor tailors its change intervals to the engine's operating conditions. The system measures trip duration, crankshaft rotations and other data to determine when it should signal the driver for an oil change. Intervals vary from 1,000 to 7,500 miles.
When the oil-change light goes on, mechanics replace a unique in-sump oil filter that uses a paper cartridge instead of the typical metal-bodied screw-on filters. Freeman says the cartridge is environmentally friendly.
'The whole idea was to try to reduce the amount of metal disposed of during the life of the engine,' he says.
The engine's assembly line in Livonia, Mich., is new, too. The LX5 will be GM's first engine to have its block, heads and crankshaft machined entirely by so-called flexible tooling stands. These stands change their own tools and positions to perform a myriad of machining functions. Currently, the Northstar's castings move through hundreds of stations where just one function is performed at each.
Now, design changes late in the development process are less costly, says engineer Allen Cline, GM Powertrain's liaison to the plant.
'It's not uncommon to spend $100,000 to rework one station on a line, whereas with (flexible tools) it's just a matter of reprogramming the machine.'
The up-front costs of installing flexible stations can be 50 percent more than a conventional line, says Cline, but 'the savings come in three years when we decide to do design changes to the engine.'
Production of the LX5 is scheduled to begin in June.