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WHAT IS A SSS CYLINDER
HEAD?
The SSS cylinder head
(#11041-U0600A) was part of the SSS package available in Datsuns outside
of the North American market. It has 1.65" intake valves, 1.38"
exhaust valves and 1.50" intake ports. These heads are sought after
by performance enthusiasts because of their small combustion chambers.
Noticed the heart shape of the chambers in the photo above (OK, it's the
shape of a diseased heart) It is also referred to as the "peanut
head"or "closed chamber head". Perhaps the "kidney
bean" head would be more appropriate. When used with flat-top
pistons, these heads were good for a static compression ratio of 9.5:1
(according to the factory manuals) when used with an L-16. Keep in mind
that the compression will be higher if the head has been surfaced (likely)
and the block has been bored. FYI, the uncut surface-to-surface thickness
of the L-series cylinder head is 107.9mm/4.248". There were a few
variations of the SSS cam. The most common version had .410" lift and
248 degrees duration. This is the same as the L-20B cam that came to the
U.S.
OTHER CYLINDER HEAD
OPTIONS:
While the original SSS head
(casting # 219) is very rare today, there are
other L-series cylinder heads that have the same combustion chambers. As a
result, these other heads are often referred to as SSS heads. The
"peanut" combustion chamber volume was approximately 41cc. These
heads will sometimes have smaller (1.30") exhaust valves and will
always have smaller intake ports (1 1/4" and 1 3/8") These
smaller intake ports are a plus for a street engine, as the 1.50" SSS
intake ports are a bit on the large side. However, if you plan on using
the factory SSS SU intake setup, it would be wise to port match the head
to the SSS intake manifold (which is 1.50")
Most Datsuns imported into this country came with an open-chamber cylinder
head (see below). The open-chamber heads found on L-18 and L-20B's had
combustion chambers of approximately 45.3cc. Most of the open-chamber
heads found on the L-16 had a chamber volume of 38.5cc.
For a performance engine, a cylinder head with peanut chambers is
preferable. The design is more efficient and less prone to detonation.
There are applications where the open-chamber design would be a better
choice. Large displacement hybird engines such as the L-22 or L-23 would
be good examples.
The following is a list of cylinder head castings and their corresponding
chamber shapes. Keep in mind that list is not etched in stone. For
example, the A87 casting can be either open or closed chamber design. The
only way to tell is to pull the head. To find your casting number, look
just below the #1 and #2 spark plugs. The number will be cast right where
the head meets the block.
Casting # chamber type
description
A87 open or closed
found on many L-18 and L-20B's. The "domestic" version usually
came with open chambers. Many of the "used Japanese import"
engines came with the peanut version of this head. Large quantities of
these used engines were imported in the 80's, so the peanut version is
fairly common. These heads usually have 1.25" intake ports and square
exhaust ports. 1.65" intake valves. Exhaust valves can be 1.38"
or 1.30" W53 closed (with some exceptions) This head is from the
Japanese market.
Some of these castings are
for factory fuel injected engines and have
notches in the intake ports to accommodate injectors. 1.25" intake
ports and square exhaust ports. 1.65" intake valves and 1.38"
exhaust valves.
219 closed The true SSS head from imported used engines or ordered from
the Datsun comp. catalog. Later versions could be ordered from the catalog
with a V912 casting. 1.50" intake ports, square exhaust ports.
1.65" intake valves and 1.38" exhaust. These are hard to find.
Any of the other closed chamber heads can be "converted' to this
design by simply opening up the intake port to 1.50" (if that's
desired) Some of these heads are marked "A87" on the side, but
have "219" cast at the front of the head, just below the timing
chain inspection plate.
210 (some have no number) open (with rare exceptions) This is the
head that came stock on the 510. Tiny 1.125" intake ports, square
exhaust ports. 1.50" intake valves and 1.30" exhaust valves.
There have been variations reported on the valve sizes. This head is
believed to be originally designed for the L-13, and engine never imported
to the U.S. I know of one that has the peanut (closed) chamber with 37cc
displacement. The earliest versions had more of a "semi-open"
chamber design but later examples were the open chamber design. These
heads are usually avoided on performance applications.
U67 open The stock cylinder head for many L-20B's. 1.375"
intake ports,
square exhaust ports. 1.65" intake and 1.38" exhaust valves.
U60 open Identical to the U67 head, this number has been found on very
early L-20B's. It seems to be fairly rare.
W58 open(with rare
exceptions) This is the L-20B smog head usually found on '77 and later
engines. 1.375" intake ports with ROUND exhaust ports. These exhaust
ports have steel liners that help burn off emissions. I know of one of
these castings that has closed chambers. These heads don't flow well and
are avoided for high-performance applications.
N56 open(?) This is
an emissions head that appears to be identical to the
W58 casting. The combustion chamber design has not been verified yet, but
is probably
open.
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