Reinforced exhaust valves BMW M3 E46 Z3M Z4M S54B32

BMW engines covered

The last naturally aspirated six-cylinder from the M division, the S54B32 displaces 3,246 cc (87 mm bore, 91 mm stroke) and was built from 2000 to 2008. It powers the E46 M3 and its lightweight CSL version, the last Z3 M models and then the E85 and E86 Z4 M. Individual throttle bodies, double VANOS and a love of high rpm make it an engine that forgives nothing in its valvetrain.

Its cylinder head carries 12 exhaust valves 11 34 7 830 888: 30.5 mm head, 6.0 mm stem, operated by rocker arms with adjustment shims. The collets are 11 34 1 461 405 up to 09/2002, then 11 34 7 833 195; the valve stem seals come from kit 11 34 9 064 457. On track, long periods at full load bring the head of these valves to the temperature range where the original steel loses much of its strength.

SUPERTECH and FERREA reinforced exhaust valves

Burnt gases leave the cylinder through the exhaust valve. The metal of its head climbs to 760 to 870 °C on an engine without forced induction such as the S54, and passes 1,000 °C once a turbo or supercharger is fitted. Close to 75 % of that heat goes out through the seat, roughly 20 % through the guide. The hotter steel gets, the weaker it becomes: an EV8-family steel, taken here as the benchmark, holds 550 MPa at 600 °C but falls to 300 MPa at 800 °C. With more load, revs or boost, the head heats up further, tires through fatigue, may warp and gradually stops sealing.

Reinforced valves rely on materials built for this level of heat: black nitride high temperature stainless steel from SUPERTECH and, first and foremost, Inconel, a nickel superalloy still rated at 860 MPa at 730 °C and 554 MPa near 815 °C, close to 85 % stronger than the benchmark steel around 800 °C. FERREA credits its Competition Plus series with 20 % greater hot strength and 25 % longer seat life. Three versions are offered for the S54: SUPERTECH black nitride stainless steel, surface hardened and smoother so less prone to friction and wear, SUPERTECH Inconel, the pick for forced induction, and the nickel-based Super Alloy of the FERREA F2360P.

A version with a head enlarged by 1 mm, the BMEVI-1045S, rounds off the range: only the head changes, from 30.5 to 31.5 mm. Burnt gases escape sooner, the cylinder takes in more fresh charge and output rises. The cylinder head seats must then be machined to this new size.

Exhaust valve technical specifications

BMEVI-1040S-LC-12: 119.1 mm version, designed for fitting with 6 mm lash caps instead of the BMW shims, and RET-BM2521/T1S-LC retainers.

Valve fitting

The SUPERTECH Inconel valves have a single groove and are fitted with KPR-6S-7 collets. The FERREA F2360P keeps its 3 grooves and takes 3 groove collets, BMW or KPR-VW6-T. These two collet types are intended for the S54.

With a 30.5 mm head, the exhaust seats keep their size and are simply checked during the cylinder head rebuild. The 31.5 mm BMEVI-1045S requires the seats to be cut to its size.

Enlarged head valves are not recommended on engines fitted with VANOS, the S54 included, because of the risk of contact between valves and pistons.

Technical guide

Our brands

	SUPERTECH, based in Silicon Valley, has spent over 30 years designing racing valves, valve springs, guides as well as titanium retainers. Whether made of stainless steel, titanium or Inconel, each valve targets one specific engine and is refined alongside well known tuners from drag racing, rallying and circuit racing.
	FERREA Racing Components, started in 1978 by Horacio Ferrea together with Daniel Urrutia, produces stainless steel, nickel alloy and titanium valves in Florida and Argentina. Engine builders worldwide trust them, from NASCAR ovals to the drag strip.

How to choose

Caught under the retainer, the collets engage the single groove or the three grooves of the stem and keep the valve in place. How many there are changes the way it is held, and so the benefit you get from it.

When reinforced valves become necessary

• Higher lift camshafts or stiffer valve springs
• Rev limit raised
• Turbo or supercharger fitted (Inconel version recommended)
• Cylinder head rebuilt for track, drift or rally
• Original valves pitted, marked or already reground to repair size

Vehicle compatibility

OEM part number (exhaust valve): 11 34 7 830 888

Don't forget the inlet valves

When rebuilding an S54 cylinder head, replace the inlet valves along with the exhaust side, and do not forget the valve stem seals. Here are the parts for this engine: