SEPTEMBER 2017 91BEN’S E36 S54 TOURING
Having spent a good few years working at this
very publication, there’s one BMW modding
staple that I am very much on board with – if
something breaks, then it’s time to upgrade
it rather than a straightforward repair or
replacement. So, with the S54 having cracked a
piston... Hell, might as well get stuck in with a
full overhaul and upgrade.
The plan is simple; drivability is off the wish
list (within reason), outright power is well and
truly on. The heart of this will be the Kofl ach
Engine Developments cams, which we’re
penning from scratch to work perfectly for this
specifi c application; the Vanos will be deleted to
allow for a longer duration than is possible with
Thomas’ set and the production versions. More
on this soon.
The bottom end will get a thorough
smattering of the highest performance parts
and processes on offer, but to begin with my
focus is the accompanying valvetrain for those
all-important cams. In my mind, I had only one
company in my mind for this; Supertech.
The problem with standard valves is that
they, even in an engine like the S54, are mass
produced and so need to be cheap. Cheap
means slacker tolerances, and this is very much
prevalent in the valvetrain. The OE valves are
made from two pieces, friction-welded together- this is generally cost-cutting as a cheaper
material can be used for the head and stem
to whatever specifi cation is required, rather
than having to use and treat one (more costly)
material for the lot. Also, almost all OE valves
use a triple-groove collet. These are great,
because neither the valve or collet have to be
made to a tight tolerance – the grooves house
the collets’ ribs and that’s what locks the valve
in place.
With a high performance valve, being made
to tighter tolerances means that a single groove
collet design can be used. While on the face
of it that sounds like a less secure method, it’s
actually far more secure, and longer lasting
because the collet grips the valve stem itself –
the groove is purely for assembly purposes. This
is a huge advantage for high-rev use where the
triple-groove design can allow the valve to fl oat
and will also damage each of the grooves over
time, eventually leading to failure.
You’ll fi nd Supertech components at the heart
of some of the world’s greatest engine builds,
and with mine there was only one approach
I was interested in – going all-out. Therefore
intake valves, exhaust valves, a spring set and
collets were ordered up. Let’s see what we’re
dealing with...
Supertech’s S54 intake valves are made
from an enhanced EV8 (21-4N) stainless steel,
which begins life as a single piece forging.
This provides the strength required for any
application, which of course helps when
the valve is being snapped shut by heavier
duty valve springs at high revs; this strength
also means that there is more freedom for
aerodynamic design of the valve for maximum
fl ow, as it doesn’t necessarily need the
thickness in areas like the stem for strength.
Precision machining and grinding for the seating
surface and stem ensure the valve is a perfect
fi t within the valve guide, stem seal and seat- the latter ensures that the seal is as perfect
as can be (when combined and lapped to a
seat in good condition) for maximum cylinder
compression and performance.
Supertech’s crowning glory with its stainless
steel valves is its black nitriding fi nish. Not only
does this provide immense hardness for minimal
wear over the life of the valve, but it also creates
a smoother fi nish for reduced friction. Another
bi-product of this process is that the valves are
far less susceptible to carbon build up, as it
simply doesn’t get a purchase on the surface.
The head of the valve is swirl-polished too,
which encourages turbulence in the combustion
chamber for increased effi ciency. Clever stuff.
Moving to the exhaust, Supertech specifi es
an Inconel valve for the S54. This exotic nickel-
based super alloy is perhaps best-known for
its use as an exhaust manifold material in high
end motorsport including Formula 1 and World
Rallycross. This is thanks to the fact that it
can withstand extremely high temperatures
and is also very strong and lightweight. Again,
Supertech’s inconel exhaust valves are made
from a single-piece forging but rather than
nitriding, they feature superfi nishing on the
stem for incredibly low friction, along with a
hardened tip.
Between them, Supertech’s intake and
exhaust valves will form a fundamental part of
what will keep my S54 singing well up in the
rev range, thoroughly exceeding the factory
valves for performance and longevity. Next
month I will touch on the springs and associated
components needed to make the most of the
valves, again courtesy of Supertech.
THANKS AND CONTACT
Supertech Performance
http://www.supertechperformance.comFresh suspension
fi nally fi ttedBilstein B16 coilovers
offer easy adjustmentGreen across the boardPBMW217.our_cars.ed2.indd 91 07/08/2017 08:36