Long-term wrapup: an informative year with two 'Best Engines' winners

The Best Engines competition has emerged as one of the industry's most anticipated "award" events. Some early critics said naming each year's best engines is a fine idea, but that spending a week or two testing the engines provides scant perspective regarding long-term durability, and reliability - or much impression of the "ownership experience."

Thus our decision to select two of each year's Best Engines winners and subject them to a year-long evaluation - to determine, in essence, if some Best Engines winners are indeed "two-week wonders," or if they can delight and perform reliably after the test of time (and mileage).

For readers who've followed our previous reports, they'll know that after roughly 40,000 miles (64,400 km) logged for both the Contour and the Millenia, nothing engine-related broke. For those just joining in we'll reiterate: no engine problems.

In fact, both engines - the Contour's sweet-revving 2.5L DOHC V-6 and the Millenia S's stunningly powerful 2.3L "Miller-cycle" DOHC V-6 - performed with nary a glitch.

Yes, the Contour's 2.5L engine did require a replacement idle-speed sensor, which was covered under warranty. That was the sum total of required repair for either engine, apart from the addition of the odd half-quart of oil, which we deem too trivial to include even in the "non-scheduled maintenance" section of our spec box.

In the course of recording just less than 41,000 miles with the Contour, we found little about which to gripe. The 2.5L Duratec V-6 always delighted drivers with heady acceleration, handy torque and creamy responsiveness. Overall fuel economy, at 26.8 mpg, was outstanding. Replacement of the idle-speed sensor cured complaints of fussy idle quality, particularly when the weather turned cold.

While we learned a lot about the Duratec, our continued grousing in print about annoying power-steering noise led to a few Ford engineers' examination of the problem once our official test was completed. We understand some minor fixes are under way to make all Contour V-6 power-steering systems a bit more quiet.

Such is the same for the Millenia S and its Miller-cycle V-6. There were those among the WAW staff who believed this engine and its new-to-the-automative-sector technology might prove to be a reliability liability.

No way. Mazda powertrain engineers did their durability homework here. The Miller-cycle V-6, which relies lies upon what amounts to an extremely sophisticated variable valve-timing system - along with a first-ever automotive use of a Lysholm screw-type supercharger - cranked out top-drawer performance from the day it arrived on into its 36,000-plus miles with WAW. We would have easily cracked the 40,000-mile barrier, but a nincompoop sullied the schedule by backing into the Millenia. It cost nearly a month in the bump shop.

"Simply stunning," read one entry in the Millenia's logbook near the end of its term, "this engine is truly amazing; explosive acceleration at 75 mph and pulls hard well into triple-digit speeds. I still don't believe there's only 2.3L of displacement at work here." Those 2.3L worked hard, but returned more-than-acceptable fuel economy - 23.6 mpg overall.

The only complaint about the Miller-cycle V-6 resulted from slightly inconsistent day-to-day performance. For example: on chilly days, the engine didn't appear to deliver full performance until completely warmed. The Miller also seemed somewhat sensitive to fuel quality (premium fuel is required). Finally, the Millenia's endearingly smooth 4-speed electronically controlled automatic transmission and the Miller V-6 at times weren't working from the same playbook, an annoyance we chalk up to poor engine-management computer (ECU)/transmission interfacing.

In a year and a combined 75,000-old miles, we believe we learned a lot about these two superb engines. We learned plenty about their respective manufacture's dealership networks (continually improving, but yet: let the owner beware). And the year saw both engines provide the degree of reliability and low-cost maintenance all consumers now expect.

We'd like to think the manufacturers learn something from these tests, too. Ford's looking at power steering noise. And for 1997, Mazda's fixed the Millenia's AWFUL cupholder design. With progress like that, we're definitely looking forward to this year's new long-term test vehicles.