Toyota 1UZ-FE 4.0L Engine Specs, Problems, Reliability. The first member of the UZ engine household is 1UZ-FE. When changed with the 3UZ-FE engine, it was a 4.0-litre V8 gasoline engine provided for high-end and sports cars of Toyota and Lexus because 1989 to 2002 and. In turn, the 1UZ engine changed the out-of-date Toyota’s V household engines, which were used from the 1960s through the 1990s.
The 1UZ-FE engine has aluminum cylinder block with thin cast-iron cylinder liners. The engine block has a 90-degree angle between the cylinder banks. The cylinder banks are displaced relative to each other by 21 mm. The engine has 6 primary bearing and a forged steel crankshaft with eight balance weights. For reduction of rotation masses the engine was equipped with robust and lightweight forged steel connecting rods, aluminum pistons, and connecting rod pins that were induction-hardened.
In late 1994, the 1UZ-FE got an even lighter crankshaft and lighter connecting rods, much shorter and thinner piston pins, and customized pistons. The engine is popular for smooth and peaceful operation. The great merit in this is the using of liquid-filled substance engine mounts. In 1997 the engine got upgrades, and one of those was the increased rigidness of the cylinder block which benefits quieter operation.
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Toyota 1UZ-FE 4.0L Engine Specs, Problems, Reliability
The design of the 1UZ engine is more common for a racing engine than a common engine for a roadway car. There are more expensive 8 counterweight crankshaft, light-weight parts, and practically square dimensions of bore and stroke. The most recognizable function is the DOHC 32-valve aluminum cylinder heads. Back in a day, a regular V8 engine has a single camshaft in a cylinder block, and OHV heads with 2 valves per cylinder. The 1UZ-FE has 2 camshafts (consumption and exhaust) and four valves per cylinder in each cylinder head.
The consumption camshafts only are driven by a timing belt, and the exhaust camshafts are driven by equipments on the consumption camshaft. The engine heads don’t have hydraulic lifters. There are solid aluminum alloy valve lifters and steel outer shim type valve adjusters on top of them. The valve stem size is 6.0 mm for both exhaust and intake valves. Consumption valve diameter – 33.5 mm, exhaust valve size – 28.0 mm. In late 1997, the diameter of valves was increased (intake valve – 34.5 mm; exhaust valve – 29.0 mm;-RRB-, while the stem size was decreased to 5.5 mm.
The initial 1UZ-FE had the easy ignition system that includes two suppliers and 2 ignition coils. Also, the 1UZ-FE engine had multi-port fuel injection (MFI) until 1994 and then changed to sequential multiport fuel injection (SFI). The Non-VVT-i engine had mechanical throttle body and its aluminum consumption manifold. The engine had EGR system (Exhaust Gas Recirculation) to bring some amount gases back inside the cylinders. The recirculation gases were cooled by coolant at the back of the engine. The EGR was gotten rid of in 1997. The exhaust system consisted of stainless steel headers and monolithic type three-way catalytic converters.
The 1UZ-FE VVT-I Engine
As was mentioned prior to 1997 was the time of substantial changes. To name a few innovations explained earlier, the 1UZ-FE engine was geared up with Variable Valve Timing system or VVT-I (I – intelligent). The throttle body now is regulated electronically and the all system got its name ETCS-I (Electronic Throttle Control System – intelligent). This system permitted managing of the idle speed, cruise control, and Automobile Skid Control system.
The engine came with the new intake manifold. It was and had long ports created to increase torque at low to mid engine rpm. The active port’s length of the intake manifold became differed by Acoustic Control Induction System (ACIS). This system uses a bulkhead to divide the length variety into 2 phases. The engines from 1997 had the greater compression ratio 10.5:1 and steel laminate type gaskets in between cylinder heads and engine block. The 1UZ-FE VVT-I had a lot of small external and internal modifications crafted to increase reliability, rigidity, performance, to lower friction and power losses, fuel consumption and emissions.
you must see more engine detail in here: Engine – US Cars News or you can see on wiki here
Toyota 1UZ-FE 4.0L Engine Specs
| Manufacturer | Tahara plant |
| Production years | 1989-2002 |
| Cylinder block material | Aluminum |
| Cylinder head material | Aluminum |
| Fuel type | Gasoline |
| Fuel system | Fuel injection |
| Configuration | V |
| Number of cylinders | 8 |
| Valves per cylinder | 4 |
| Valvetrain layout | DOHC |
| Bore, mm | 87.5 (3.44 in) |
| Stroke, mm | 82.5 (3.25 in) |
| Displacement, cc | 3,968 cc (242.1 cu in) |
| Type of internal combustion engine | Four-stroke, naturally aspirated |
| Compression Ratio | 10.0:1 10.4:1 – since late 1994; 10.5:1 – since 1997 (VVT-i engines); |
| Power, hp | 251-261 hp (191-195 kW)/5,400 – non VVT-i; 290-300 hp (216-224 kW)/5,900-6,000 – with VVT-i; |
| Torque, lb ft | 260-269 lb-ft (353-365 Nm)/4,400 – non VVT-i; 300-310 lb-ft (407-420 Nm)/4,000-4,100 – with VVT-i; |
| Engine weight | 364 lbs (165 kg) |
| Firing order | 1-8-4-3-6-5-7-2 |
| Engine oil weight | 5W-30 |
| Engine oil capacity, liter | 5.0 (0.3 – oil filter) – 1989-1994 models; 5.1 (0.3 – oil filter) – 1994+ models. |
| Oil change interval, mile | 6,000 (10,000 km) or 12 month – 1989-1994 models; 9,000 (15,000 km) or 12 month – 1994+ models. |
| Applications | Lexus GS 400, Lexus LS 400, Lexus SC 400, Toyota Aristo, Toyota Celsior, Toyota Crown, Toyota Soarer |
Toyota 1UZ-FE 4.0L Engine Problems and Reliability
Someone say it will last permanently, however honestly 300,000 miles is a considerable number. There are not numerous engines went far than that. Still, the 1UZ’s durability is absolutely outstanding. With appropriate maintenance, it does not knock, leakage or burn a single drop of oil.
For big mileage automobiles, it is common problems with external engine parts such as water pump, alternator, and starter. The last one is required so much work simply to take it off. The spark plugs are sensitive to a fuel quality. Do not use a bad fuel otherwise, it will result in costly spark plug replacing soon (it is pricey due to a no-easy and time consuming changing process for this engine).
The 2nd gen 1UZ (late 1994+) and VVT-I engines can suffer severe damage if the timing belt breaks. Watch on timing belt condition and alter it according to the Toyota’s maintenance schedule. Likewise, the very first gen 1UZ-FE is a bit over-engineered and has beefier and more powerful pistons, linking rods, etc. In this case, they produce less power however have more durability, strength, and smoothness fundamental for luxury cars.