Reinforced inlet valves BMW B58B30

BMW engines covered

The B58B30 is BMW's 3.0 litre turbocharged inline six, with roller finger followers, hydraulic lash adjustment and Valvetronic variable lift on the inlet side. Since 2015 it has powered the M140i, M240i, 340i, M340i, 440i, 540i and Z4 M40i, with 326 to 387 hp depending on version.

Its 12 inlet valves are BMW 11 34 7 633 699: 30.1 mm head, 5 mm stem, held by collets 11 34 1 438 142. A remap that raises boost exposes them to more heat and harder impacts.

SUPERTECH and FERREA reinforced inlet valves

The inlet valve opens the way for the air compressed by the turbo, strikes its seat on every closing and slides constantly in its guide. It runs at 400 to 550 °C; at these temperatures the original chrome-silicon steel drops from 500 MPa at 500 °C to 250 MPa at 600 °C, 50 % of its strength lost.

The SUPERTECH valve is cut from a racing stainless steel of the EV8 family: 650 MPa at 500 °C, 30 % better than the original steel, and 550 MPa at 600 °C, 120 % better; black nitriding makes the stem harder and smoother in its guide. The FERREA valves belong to the Competition Plus series, for which the manufacturer states 20 % more hot strength and fatigue resistance, and a seat that lasts 25 % longer.

FERREA adds a +0.5 mm oversize: the head grows from 30.1 to 30.6 mm, the stem stays at 5 mm. Air flows through a wider opening and the cylinder fills better, provided the inlet seats are cut to this new size.

Inlet valve technical specification

MCIVN-1400S-12: to be fitted with KPR-5.0-7S collets.

Fitting details

With its single groove, the SUPERTECH valve is fitted only with KPR-5.0-7S collets, never with the original ones. The FERREA valves keep 3 grooves and take 3-groove collets for a 5 mm stem.

The +0.5 mm version requires the inlet seats to be cut to its size; at standard size, the seats are checked and refreshed as usual during the cylinder head rebuild.

Clearance is taken up hydraulically: no adjustment is needed after replacing the valves.

Technical guide

Our brands

	SUPERTECH, based in San Jose, California, has been designing valves, springs, retainers and guides for racing for more than 30 years. Each valve is drawn for a specific engine, checked by ultrasound, X-ray and laser measurement, then proven with engine builders from circuit racing to drag racing.
	FERREA Racing Components has been based in Fort Lauderdale, Florida, since 1978, when two engine builders of Argentine origin started it. Each valve is forged in one piece from bar stock, then machined end to end on CNC machines; the brand races in NASCAR and drag racing.

How to choose

The groove is the notch holding the collets that keep the valve under the retainer: their number decides which collets to fit and how the valve holds up at high rpm.

When reinforced valves become necessary

• Sharper camshafts or firmer springs
• Raised rev limit
• Higher boost or a larger turbocharger
• Cylinder head rebuilt for circuit or track use
• Original valves marked or worn

Compatible vehicles

OEM part number (inlet valve): 11 34 7 633 699

Related products

A rebuilt B58 cylinder head also gets new exhaust valves. They are offered here: