The Toyota UZ-series Engine Guide

Japanese auto manufacturers aren’t renowned for their V8s but the Toyota UZ-series bent-eight most surely be one of the sweetest on the planet. A visit to any large Japanese import wrecker will also reveal that these engines are cheap and plentiful – the ideal engine for a conversion.

So what is the background of the UZ-series engine? Let’s take a look...

Early UZ Engines

The first in the family of UZ-series engines is the 4-litre 1UZ-FE which was introduced in the late 1989 Japanese Toyota Celsior (aka Lexus LS400).

The all-alloy 1UZ-FE uses over-square bore/stroke dimensions (87.5 x 82.5mm) to achieve a total displacement of 3968cc. The bullet-proof bottom-end uses a steel crank with six bolt main bearing caps and the compression ratio is set to a relatively high 10:1. As a result, premium unleaded fuel is recommended though the engine does feature twin knock sensors. The 1UZ-FE draws air through a pair of DOHC, four-valve-per-cylinder heads and a multi-point injection system with a fixed length/volume induction system. Most early 1UZ-FEs are also equipped with electronic traction control which uses a secondary throttle valve.

Japanese versions are rated at 191kW at 5400 rpm together with 353Nm at 4600 rpm, while Australian delivered versions (from early 1990) make 1kW and 3Nm less. It is claimed that 90 percent of peak torque is spread from 2000 to 5600 rpm but, curiously, it doesn’t feel that way – the engine seems to come alive at around 4000 rpm.

Note that all UZ-series V8s are mated to an automatic transmission – there has never been a Toyota V8 tied to a manual ‘box. All UZ-powered cars are also rear-wheel-drive with the exception of two vehicles – the Aristo AWD and Land Cruiser/LX470.

In 1990, the same 191kW/363Nm spec engine was made available in the UZS131 Toyota Crown saloon. An updated Crown (the UZS141 Crown Majesta) was released in ’91 but there were no major engine changes. In the same year, the Soarer GT was also introduced with 1UZ-FE grunt - again, power and torque remained at 191kW/353Nm.

During 1992, an AWD version of the 1UZ-FE appeared in the Toyota Aristo 4.0Z i-Four (chassis code UZS143). Output holds at 191kW/353Nm and the attached four-speed auto transmission apportions torque to all four wheels. This would be an ideal set-up for an all-out home built vehicle.

In 1994/1995, the 1UZ-FE received a slight upgrade. The compression ratio was bumped up to 10.4:1 (making the use of premium unleaded even more important), it appears that the headers were improved and output was lifted to 195kW and 363Nm. This upgrade was applied across the Celsior, Crown and Soarer range. It appears that the AWD Aristo (which was discontinued in around 1997) stayed at 191kW/353Nm.

In 1997, the Celsior’s 1UZ-FE adopted Toyota’s VVT-i variable valve timing and ACIS variable induction system. With these changes and yet another compression ratio increase (to 10.5:1), the 1UZ touches the contemporary Japanese regulation output – 206kW at 6000 rpm. Peak torque also breaks the 400Nm barrier with 402Nm on tap at 4000 rpm. At the same time, electronic throttle control was added and the previous four-speed auto trans was replaced by a ‘Super Intelligent’ five-speed auto. The same engine/trans combo was adopted by the Crown Majesta in ’98. The Crown continued using the 4-litre 1UZ-FE VVT-i until the early 2000s.

Late Model and Large Capacity UZ Engines

In 2000, the flagship Celsior dropped its 4-litre 1UZ-FE in favour of a bigger 4.3-litre 3UZ-FE engine.

The 3UZ offers 0.3-litre extra capacity (thanks to a larger 91mm bore) but retains much of the same design characteristics – VVT-i, variable induction system, a 10.5:1 compression ratio and electronic throttle control. Not surprisingly, the bigger engine makes peak power at lower revs than the 4-litre – 206kW arrives at 5600 rpm while there’s a healthy 430Nm at just 3400 rpm. A five-speed auto and rear-wheel-drive remain. In Australia, the 2000 Celsior is badged as the Lexus LS430 - in local guise, the 3UZ engine has 13Nm less torque than the Japanese version.

After being axed in the late ‘90s, the Soarer coupe re-emerged with Toyota V8 power as standard. The 2001 UZZ40 Soarer 430SCV cruises with same 206kW/430Nm 3UZ-FE and five-speed auto as fitted to the Celsior. Curiously, the Australian delivered version, known as the Lexus SC430, is listed with more power but less torque – 210kW and 419Nm.

There were no significant engine changes until, in late 2003, the 3UZ was equipped with a six-speed automatic transmission. This improved accessibility of performance and fuel consumption in normal driving.

In 2004/2005, the Lexus GS430 mid-size salon was introduced. The GS430 carries the 4.3-litre 3UZ-FE V8 generating the same output as the Celsior and Soarer (aka LS430 and SC430). To date, these are the only remaining vehicles using Toyota V8 power. A new flagship model is expected for release later this year – the thumping big 4.6-litre V8 Celsior/LS460. We can’t wait!

But the biggest member of the UZ engine family can be found in the rock-crushing 100 series Toyota Landcruiser/Lexus LX470 released in 1998. With nearly 2.5 tonnes to shift, Toyota saw it necessary to bore and stroke the UZ design to 94 and 84mm respectively. We believe that the Landcruiser’s block is unique and, unlike the rest of the UZ family, it's cast iron. The enlarged bore and stroke achieves a displacement of 4.7-litres and creates the engine known as 2UZ-FE. With the compression ratio dropped to 9.6:1, the 2UZ-FE is more about torque than top-end power – in Japanese guise, there’s 422Nm at 3600 rpm and 173kW at 4800 rpm. Australian versions are rated at 170kW and 410Nm. Drive is to all four wheels via a four-speed auto transmission. A five-speed auto was fitted from mid 2002.

From a buyer’s perspective, the late-model and Landcruiser/LX470 UZ-series V8s fetch a considerable amount of money but the earlier examples can be picked up dirt cheap. The cheapest way to get a 1UZ-FE is to purchase a bare import engine (minus transmission and wiring) – this costs around AUD$1150 (see www.adelaidejap.com.au). On the other hand, it might be wiser to purchase one of the unloved Crown V8s which are currently available from www.home.iprimus.com.au for just AUD$4000 – this approach gives you the matching transmission, ECU(s), airflow meter and wiring. Oh, and you also get a free Toyota Crown body...

With the Toyota UZ-series, re-powering with a sophisticated DOHC V8 has never been cheaper or more achievable!

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