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Reinforced valve spring kits VAG 4.2 V8 40V BHF

Reinforced valve spring kit VAG 4.2 V8 40V BHF

€1,396.20 (tax incl.)

€1,745.26 (tax incl.) -20%

Kit of 40 reinforced valve springs for VAG 4.2 40V V8 engines (BHF, BAS, AXQ, BGH, BGJ).

Brand: SUPERTECH
Engines: V8 4.2 40V, codes BHF, BAS, AXQ, BGH, BGJ
Springs: single on the inlet, double on the exhaust
Contents: springs, titanium upper retainers

Audi and Volkswagen engines covered

This kit is made for the 4.2 litre 40-valve V8 of the VAG group, with five valves per cylinder: it powers the Audi S4 in its B6 and B7 generations (code BHF) and the allroad C5 4.2 (code BAS), along with the Volkswagen Touareg (code AXQ) and Phaeton (codes BGH and BGJ).

The tappets of these engines take up lash hydraulically. Each cylinder head leaves the factory with 077 109 633 F springs on the inlet side and 077 109 623 C springs on the exhaust side, topped by 077 109 641 G (inlet) and 077 109 641 H (exhaust) upper retainers, and fitted with 036 109 675 A stem seals.

SUPERTECH reinforced valve spring kit

The spring closes the valve onto its seat as the cam rolls away and keeps it against the lobe. At high revs a valve may lift off, bounce and strike the piston, which is called valve float.

The kit pairs 24 single inlet springs with 16 double exhaust springs and titanium retainers: 258 N and 334 N at the seat, 592 N and 801 N at lift.

Valve spring kit technical specification

Part number	Brand	Springs	Outer / inner Ø	Seat pressure	Open pressure	Rate	Max lift	Kit contents
SPRK-AUDI42T	SUPERTECH	Inlet single Exh. double	Inlet 20.6 / 14.4 mm Exh. outer 29.1 / 21.9 mm Exh. inner 20.5 / 15.5 mm	Inlet 258 N at 36.6 mm Exh. 334 N at 33.7 mm	Inlet 592 N at 11 mm Exh. 801 N at 10.5 mm	Inlet 29.8 N/mm Exh. 44.5 N/mm	Inlet 11.0 mm Exh. 12.0 mm	40 springs, 40 titanium upper retainers, 16 lower spring seats

Valve spring kit fitting details

Part	VAG original	Reinforced spring kit
Spring	Inlet 077 109 633 F; exh. 077 109 623 C	Kit specific
Retainer	Inlet 077 109 641 G; exh. 077 109 641 H	Kit specific
Spring seat		Kit specific: SEAT-H1000 on exhaust, original kept on inlet
Collets		Original kept

The SUPERTECH SPRK-AUDI42T kit contains 24 single SPR-A2095 springs for the inlet side and 16 double SPR-H1002D springs for the exhaust side, 24 titanium upper retainers RET-AU5VI/T2 (inlet) and 16 RET-AU5VE/T5 (exhaust), plus 16 SEAT-H1000 lower spring seats on the exhaust side. The original collets and stem seals stay in place.

Install height is measured with the valve shut, from the face where the lower spring seat rests up to the face of the upper retainer. Every load listed for this kit belongs to its own height in the table below. If that height increases once the seats are refaced, the spring relaxes and loses its rate times the length gained.

	SUPERTECH
Installed height	Inlet 36.6 mm Exh. 33.7 mm
Seat pressure at this height	Inlet 258 N Exh. 334 N

Technical guide

Our brands

SUPERTECH, a firm based in California, has supplied valvetrain hardware to motorsport for thirty years. Its springs are made of chrome-silicon-vanadium alloy steel, its retainers of aerospace titanium, and each production run is verified by ultrasound, radiography and laser scanning.

How to choose

With stiffer springs the engine revs higher, accepts a more aggressive cam or more turbo without float. The kit gives 258 N at the seat on the inlet side and 334 N on the exhaust side, then 592 N and 801 N at lift. Before buying, confirm that your cam lifts under 11.0 mm on the inlet and 12.0 mm on the exhaust, the kit limits.

Criterion	Key point
Choosing the pressure	Pick the load by setting cam lift against the target engine speed; the higher both climb, the more rate counts. At the seat the kit is listed at 58 lbs inlet and 75 lbs exhaust, or 258 N and 334 N. Chasing the strongest load is a mistake: an excessive spring wears cams and crushes hydraulic tappets. A rate of 29.8 N/mm (inlet) and 44.5 N/mm (exhaust) gives the load added per millimetre squeezed.
Single or double spring	In a double spring two coils of different diameters work together: load rises at equal volume and vibrations are damped better. The inlet keeps a single spring here, while the more heavily loaded exhaust receives a double one. The kit contains springs and upper retainers; on the inlet the original lower seats are still used, on the exhaust you fit the SEAT-H1000.

When reinforced springs become necessary

Cam with more lift than the original
Higher rev ceiling through the engine map
More turbo pressure or a bigger turbine
Rebuild for circuit, rally or drift use
Worn springs or valve bounce near the limiter

Compatible vehicles

Model	Engine code	Years
Audi A4 B6 (8E2 / 8E5) S4 quattro	BHF	2003-2004
Audi A4 B6 Cabriolet (8H7) S4 quattro	BHF	2004-2005
Audi A4 B7 (8EC / 8ED) S4 quattro	BHF	2004-2008
Audi A4 B7 Cabriolet (8HE) S4 quattro	BHF	2005-2009
Audi allroad C5 (4BH) 4.2 V8 quattro	BAS	2002-2005
VW Touareg (7LA / 7L6 / 7L7) 4.2 V8	AXQ	2002-2006
VW Phaeton (3D) 4.2 V8 4motion	BGH / BGJ	2003-2016

OEM part number (valve spring): inlet 077 109 633 F; exhaust 077 109 623 C

Important: this kit is for the 4.2 litre 40-valve V8 engines BHF, BAS, AXQ, BGH and BGJ; the 3.6 litre FSI V6 engines of the same group are not covered. Check your engine code before ordering.