Before the days of SR and QR-series Nissan motors,
the hottest four-bangers on the market were the FJ and CA-series. The early ‘80s
FJ has earned a reputation for massive strength and the potential for huge
power, while the CA18ET/DET are sophisticated and relatively lightweight engines
with plenty of aftermarket accessories to back them up.
In this article we trace the evolution
of the Nissan FJ and CA-series performance fours...
FJ-series
Nissan’s FJ-series engine was the class leading
Japanese four-cylinder in terms of power and sophistication.
Released in the late ‘81 Japanese-market DR30
Skyline RS2000, the base-spec FJ20E came naturally aspirated. The FJ uses an
89mm bore and 80mm stroke to achieve a total displacement of 1990cc.
Interestingly, the block is cast iron but the cylinder head is an alloy DOHC,
four-valve-per cylinder unit. A multi-point injection system (we believe the
first to use sequential fuel delivery), double chain cam drive, 9.1:1
compression ratio and a fixed length intake manifold are also employed. At a
time when most 2-litre fours struggled to generate 100kW, the FJ20 raised the
bar with its 110kW at 6000 rpm and 181Nm at 4800 rpm.
And then there was the turbocharged version...
In 1983, the DR30 Skyline RS-X was made available
with a turbocharged version of the FJ four – the FJ20ET. The ’83 FJ20ET employs
a reduced static compression ratio (8.0:1) and a Garrett T03 turbocharger
without intercooler. Standard output is 140kW at 6400 rpm and 226Nm at 4800 rpm.
An update in ’84 brought an air-to-air intercooler, a slightly smaller
turbocharger (to improve response), an 8.5:1 static compression ratio and some
extra boost pressure – 7.5 psi versus 6.5 psi as previously. These changes give
the ‘Plasma’ FJ20ET 151kW and 245Nm.
The FJ had been an expensive product for Nissan to
produce, so the engine was also released in the S110 and S12 Silvia RS (aka
Gazelle/200SX). We believe the S110 and S12 spec FJ20E engines are identical to the
version fitted in the contemporary Skyline and output remains at 110kW/181Nm. A
turbo version of the FJ also came fitted in the S12 Silvia RS-X. The S12-spec
FJ20ET is essentially the same as found in the Skyline except the intake and
exhaust manifolds were revised to fit in the smaller engine bay. Power appears
to remain at 140kW at 6400 rpm and 226Nm at 4800 rpm.
Both naturally aspirated and turbo versions of the
FJ20 are designed for longitudinal mounting and rear-wheel-drive. Most FJs come
attached to a five-speed manual ‘box but autos were also available in the
updated R30 Skyline.
Interestingly, Nissan also produced a larger bore
and stroke 2.4-litre version of the FJ four – the FJ24. As far as we’re aware,
this engine was intended for Group B competition use in the early ‘80s BS110
240RS limited edition. Strangely, despite the availability of EFI on production
FJs, the FJ24 uses twin Weber carburettor induction. The compression ratio is
set at around 11:1 (requiring ultra high octane fuel) and larger ports improve
top-end breathing. Output for this motor is an incredible 177kW at 7200 rpm and
235Nm at 6000 rpm. An updated model (with a dry sump and more aggressive cams)
makes even more power! These are very thin on the ground.
The FJ-series engine is immensely strong and is
widely labelled the forefather of the ever-popular Nissan SR-series four. This
is a true modern classic.
CA-series
The Nissan CA-series was a relatively short-lived
engine that was phased in near the end of the FJ20 period and was discontinued
just a few years after with the advent of the SR series.
The first high-performance application of the CA
was the turbocharged CA18ET in the updated S12 Silvia. Using an 83mm bore and
83.6mm stroke (a longer stroke than the FJ20), the CA18 displaces a total of
1809cc. Like the FJ, the CA engine employs a cast iron block combined with an
aluminium head but camshaft drive is via a toothed rubber belt rather than
chains. Many people claim the CA is essentially a RB-series in-line six with two
cylinders chopped off.
Interestingly, Nissan released SOHC and DOHC
versions of the turbo CA18. The SOHC version uses two-valve-per-cylinder
breathing and comes non-intercooled but, curiously, employs two spark plugs per
cylinder. With a small T2 turbocharger, output is up to around 100kW depending
on market. It appears the SOHC CA18ET was fitted to the US/UK-spec 200SX Turbo
(aka Silvia), UK Nissan Bluebird and was available in the Japanese market.
But more interesting is the DOHC version.
The CA18DET uses a DOHC, four-valve-per-cylinder
head, a larger T25 turbo, 8.5:1 static compression ratio and electronic
controlled boost pressure. Early versions of this engine were employed in the
updated S12 Silvia (in rear-wheel-drive guise) and U11 Bluebird (in
front-wheel-drive guise). Still without an intercooler - just a finned
cross-over pipe - the early CA18DET generates 121kW.
When the S13 Silvia/180SX and U12 Bluebird
SSS were released in the late ‘80s, the CA18 received some minor mods including
a revised intake manifold and fitment of an air-to-air intercooler (front
mounted in the S13 and top mounted in the U12). In either spec, the late CA18DET
puts out 130kW at 6400 rpm and 225Nm at 4000 rpm. Five-speed manual or
four-speed auto transmissions are available.
A naturally aspirated DOHC version of the CA – the
CA18DE – was also available in vehicles such as the S13 Silvia and U12 Bluebird.
Without the aid of a turbocharger, these engines generate around 100kW – not a
lot in absolute terms, but they’re a good choice for lightweight kit cars
requiring strong throttle response and a revy nature.
Take a walk through your nearest
Japanese import yard and you’ll realise the FJ-series engine is now pretty
difficult to find. In many instances, you’ll have more luck searching through
local classifieds to find examples that’ve been imported and dropped into a car
several years ago – the FJ was a popular choice for conversions into the local
Bluebird and 1600. In the CA family, there’s a limited number of SOHC examples
in Australia but you can find them in the US and UK (where they were originally
imported). The DOHC CA18DET is an extremely underrated engine and you can find a
strong supply at the importers – but they won’t last too much longer!
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