Hitachi made SU carbs under license for Datsun and other Japanese
manufacturers. The Datsun carbs for the Z car were 1.75" (44mm) Hitachi's.
There are several variations on them but other than one model which was a
different size, shape and design (and never work well at all), they were
all pretty much the same. The odd ball is known as the flat top because
the dashpot is flat topped with a sharp edged rather than the ususal
slopping top with a curved edge. Although this carb is bigger (around 50mm
I think) it is to be avoided as it was always having problems. The earlier
styles were quite similar to British SU's and will fit the same manifolds
and air cleaners as an HS6. The linkage is different though and British
linkage (the linkage between the carbs) won't work. They also use a
different choke linkage. They have a dual choke cable (one handle, two
cables) that operates the chok levers directly rather than having an
interconnect linkage between the two chokes. These can still be purchased
new, by the way. Most used ones are in no better shape than the British
SU's, and the cost to rebuild them is the same.
Datsun also used SU's on some of its 4 cylinder cars (not here in
the US but elsewhere and in their racing efforts), so there are 1.5"
(38mm) Hitachi's available. They may be round or flat topped in design.
the flat topped 1.5" SU's have nothing to do with the flat topped Z carbs.
They simply used a slightly different shaped dashpot, all the rest of the
design is standard SU. These flat topped 1.5" carbs work quite well and in
fact were the SSS (triple S) comp set up for 1973 510's. As with the Z car
carbs these are available new and most of the used ones you see will be in
need of a rebuild. They will fit the same manifold and air cleaner as an
HS4. The same linkage and choke problems exist as for the Z car carbs.
Many Japanese cars came with SU or other variable venturi/cv type
carbs but not here in the US. Here they felt they had to have that
American looking two barrel carb to make us fell more familiar with the
carb and idnetify better with it. The Z car is one of the few that
actually got sent to the US with its SU on it. Had they not had FI coming
up I think they would have developed some sort of two or four barrel carb
for the Z, but they were already working on the FI designs.
On the subject of what engines were similar, the original Datsun
sports car was released sometime in the mid 50's and was called the
Fairlady (not the same thing as the Fairlady Z, they kept the Fairlady
name for use in most of the world but not the US, to differentiate between
an earlier Fairlady and the new Z car which was also called a Fairlady,
they named it the Fairlady Z). the original Fairlady lokked very much like
a big Healey, complete with two tone paint and sloping body line. The
engine was a BMC B series engine (1500 cc at first then 1600 cc later I
believe) as used in the MGA, but made under license by Niassan. Another
interesting point, the Borg Warner automatic trans used by BMC/BL was also
used by Datsun and after a year or so they started making that under
license as well (it is the only example I know of where the Japanese
version was worse than the original, usually the Japanese version is at
least as good if not better than the orignal. So if you are looking for an
automatic for your MGB look for the Datsun trans (either out of a 510 or
the stouter version out of a Z car) but remember you will still need an
MGB bell housing. And yes the L series motors (asused in the Z in a 6 cyl
version and the 510 in a 4 cyl version) were based on the MB engine, in
fact I believe they were a design under license to MB, though I could be
wrong on this.
Can you tell I specialize in British and Datsun, or what?
Marc Sayer
Performance Engineering
1070 W. 2nd Ave.
Eugene OR 97402
(503) 484-0904 Fax 746-0863
msayer@efn.org
|