When Did The UZ Family Of Engines Begin?
When Toyota released the 1UZ - FE engine in 1989, they offered it first in the Lexus LS400 to make a statement. The engine was an oversquare 4.0L all-aluminum V8 powerplant with 32 valves, hypereutectic pistons, aluminum cylinder heads, steel connecting rods, and a steel crankshaft. Toyota gave the motor a 3.44-inch bore and 3.25-inch stroke, which helped the smooth-running engine produce 250 hp and 265 lb-ft of torque.
The Toyota UZ engine had 90 90-degree configuration with an all-aluminum engine block and cylinder heads, which made the engine relatively light considering the engine’s size (quad camshafts tend to take up quite a bit of room). A cast aluminum intake manifold was employed, and the Japanese automaker reinforced the block with six cross-bolted main caps. Both the water pump and camshafts were belt-driven. Multi-port fuel injection ensured the precise measure of fuel in each chamber, and the four valves (two intake and two exhaust) ensured adequate air/exhaust flow.
With its debut, the opulent LS400 offered more value than many luxury cars of its day. The powerplant was more potent, durable, and quieter, and the car cost less than the competition. Combined with significantly lower maintenance costs, the car offered better amenities than its competition. Lexus began to develop a reputation for exceptional luxury value, which is a distinction that Toyota has been careful to maintain to this day.
The Toyota 1UZ-FE Engine Gets Even Better.
It wasn’t long before the UZ Series Lexus engine powered more vehicles in the Toyota/Lexus luxury lineup. Most reviewers could not praise the new car and its special V8 engine enough. Reviewers were astonished at how quiet and smooth the new 1UZ-FE truly was. Lexus decided to demonstrate that concept with a commercial showing a stack of carefully placed champagne glasses on the hood while the engine revved full throttle at over 140 mph. The ad claimed that the “Lexus was designed to stir the soul, and not much else.” (The ad remains one of the most memorable car ads in automotive history).
The engine received updates in 1995 and 1997, which boosted power outputs slightly. The ‘95 version received lighter connecting rods, while in ‘97, Toyota added Variable Valve Timing (VVT-i) to the UZ engine, taking the power output up to 290 hp and over 300 lb-ft of torque while also improving fuel efficiency. The 1UZ-FE engine would receive a nomination to the Ward’s Top Ten engine list for several years in the late nineties.
The Toyota 2UZ-FE Is Born.
Buoyed by the success of the 1UZ-FE, Toyota saw an opportunity to apply the lessons they had learned to its line of trucks and SUVs. Knowing trucks needed more low-revving torque, Toyota replaced the aluminum block with a cast iron to improve the motor’s rigidity. With a bore of 3.70 inches and a stroke of 3.31 inches, the motor had an increased displacement (4.7L). The motor first appeared in the 1998 Toyota Land Cruiser and Lexus GX470 1998. A year later, the engine appeared in the ‘99 Toyota Tundra and eventually in the 2000 Sequoia and ‘02 4Runner.
Besides the block and bore diameter changes, the 2UZ-FE features many of the same components as its luxury car twin, including VVT, four valves per cylinder, multi-port fuel injection, and aluminum intake manifold. The engine uses a direct ignition system with coils for all eight cylinders rather than a distributor. The power output varied throughout its production run, depending on the vehicle's market, with most 2UZ-FE engines producing between 228 - 275 hp with 311 - 315 lb-ft of torque.
The cast iron block makes the 2UZ-FE engines consistent performers, but classic car restorers do not highly desire them as the 1UZ family of engines. However, that does not mean that additional horsepower cannot be made. Tuners have boosted power outputs on the 2UZ engines with relative ease by simply using a bolt-on supercharger kit. One of the reasons that 2UZ-FE isn’t as well-loved is that throwing a ton of boost into the engine can create issues with weak connecting rods due to the use of the two bolt main caps.
The Final Member Of The Family - 3UZ-FE
The final member of the UZ family of V8 engines was the 3UZ-FE that first appeared in the Lexus LS 430 and GS 430. This 4.3L all-aluminum engine, with alloy block and cylinder heads, produced 290 - 300 hp and 325 lb-ft of torque. With a bore size of 3.58 inches, it shares the same stroke length as the 1UZ engines. Toyota ended up using the third-generation UZ engine in many of its 2000 - 2010 sports and luxury cars.
The engine uses a DOHC configuration with four valves per cylinder. Toyota applied SEFI (Sequential electronic fuel injection), which, coupled with the VVT-i, helped create a very acceptable fuel economy for a luxury vehicle. The cast aluminum exhaust manifolds were carried over from the previous generations. The 3UZ-FE does have thinner cylinder walls, which poses problems for boosters, which is another reason that the 1UZ-FE is the preferred engine of choice for the classic car enthusiast.
During its production, Toyota tinkered with a couple of variants of the 3UZ-FE motor for their race engine platform. The 4.5L version was used until 2009; a 5.0L version was used in the Grand American Road Racing Series.
Were The UZ Family Of Engines Reliable?
There is no question that the Toyota UZ Series V8 engines were some of the best examples of Japanese execution ever made. The motors were sturdy workhorses that repeatedly proved themselves as they impressed customers with their power, performance, and quality. A Toyota UZ engine is more than capable of running well past 200k miles if properly maintained. (Many reports exist of these automobiles running 350k - 400k without needing any major repair). The legendary engine may have powered many of Toyota’s luxury offerings for almost 24 years. Still, it also helped to win Lexus a loyal and committed following, catapulting the brand into one of the most well-respected luxury automakers in the world.
What Are The Issues With The UZ Family Of Engines?
There is an adage that you should never mess with perfection, and this proved true in the case of the UZ engines. The later versions of the motor are less dependable than the first generation, with a few integrity issues.
The 2UZ-FE has a cast iron block, which can make it cumbersome and heavy, and the 3UZ-FE has cylinder walls that tend to fail if too much forced air induction is used. While the engines were well made, Toyota eventually replaced them with the UR family of V8s.