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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