Reinforced exhaust valves BMW M5 E60 M6 E63 S85B50

BMW engines covered

BMW's only production V10, the S85B50 displaces 4,999 cc with the same cylinder dimensions as the S65 V8 (92 x 75.2 mm). Built from 2004 to 2010, it powers the E60 M5 saloon, the E61 M5 Touring and the E63 coupe and E64 convertible M6.

With four valves per cylinder, it has 20 exhaust valves with a 5 mm stem and a single groove, fitted with BMW collets and valve stem seals that are kept with these valves. Long periods at high rpm, on track or on the German autobahn, keep the exhaust ports very hot.

SUPERTECH reinforced exhaust valves

The head of an exhaust valve sits right in the stream of burnt gases: on a naturally aspirated engine such as the S85, its metal runs between 760 and 870 °C, and goes beyond 1,000 °C with a supercharger. The seat removes about 75 %, the guide about 20 %. Taking an EV8 family steel as a benchmark, strength falls from 550 MPa at 600 °C to 300 MPa at 800 °C: an overheated head ends up distorting and leaking.

Made from Inconel, the SUPERTECH BMEVI-1065 keeps 1,100 MPa at 649 °C and 554 MPa at 816 °C, about 85 % more than EV8 steel at 800 °C. It keeps the 30.5 mm head, 110.2 mm length and single groove of the BMW part, allowing a direct replacement.

Exhaust valve technical specifications

Valve fitting

With its single groove, identical to the BMW part, the BMEVI-1065 is fitted with the original collets, ideally new.

The head diameter stays at 30.5 mm; the exhaust seats only need checking during the rebuild, with no cutting to another size.

On the S85, the BMW valve stem seals are kept.

Technical guide

Our brand

SUPERTECH Performance, a Californian maker of racing valvetrain parts for more than thirty years, offers an Inconel exhaust valve to the original dimensions for BMW's S65 V8 and S85 V10.

How to choose

The S85 has a single version; this is how it compares with the BMW part:

When reinforced valves become necessary

• Supercharger installation (Inconel version, the only one available)
• Changed camshafts or valve springs
• Frequent track use
• Rebuilt head with pitted original valves
• Preparing a V10 M5 or M6 for racing

Vehicle compatibility

OEM part number (exhaust valve): 11 34 7 833 774 / 11 34 7 838 294

Don't forget the inlet valves

A stripped V10 cylinder head is the time to change the inlet valves too: