Reinforced valve spring kit Mazda MX-5 1.6 B6

€889.13 (tax incl.)

Reinforced valve spring kits for the 1.6 16V B6 engine of the Mazda MX-5.

Brand: SUPERTECH
Engines: B6 1.6 16V (MX-5 NA and NB)
Springs: double
Contents: springs, upper retainers, lower spring seats

Mazda MX-5 1.6 engine covered

This kit is aimed at the 1.6 litre 16-valve four-cylinder of the Mazda MX-5 (Miata): first generation NA from 1989 to 1998, including the turbo version, then second generation NB from 1998 to 2005.

The kit's double springs replace the factory ones, supplied with their lower spring seats; the standard collets keep being used.

SUPERTECH reinforced valve spring kit

Each valve closing depends on its spring. At high speed the cam throws the valve hard: if the spring is too soft, the valve bounces on its seat or returns late towards the piston. Engine builders call this valve float.

Seat pressure: 218 N at 36.8 mm for the SPRK-MM16D-1, 311 N at 34.2 mm for the SPRK-MM16D-2 (double springs).

Valve spring kit technical specification

Part number	Brand	Springs	Outer / inner Ø	Seat pressure	Open pressure	Rate	Max lift	Kit contents
SPRK-MM16D-1	SUPERTECH	Double	Outer 27.5 / 20.0 mm Inner 20.0 / 15.2 mm	218 N at 36.8 mm		53.8 N/mm	12.9 mm	16 springs, 16 upper retainers, 16 lower spring seats
SPRK-MM16D-2	SUPERTECH	Double	Outer 27.5 / 20.0 mm Inner 20.0 / 15.2 mm	311 N at 34.2 mm		53.8 N/mm	12.9 mm	16 springs, 16 upper retainers, 16 lower spring seats

Valve spring kit fitting details

Part	Mazda original	Reinforced spring kit
Spring		Kit specific: SPR-TS1015 (double)
Retainer		Kit specific: RET-TS60/MA2
Spring seat		Kit specific: SEAT-TS/MA16 or SEAT-TS/MA18E
Collets		Original kept

Each SUPERTECH kit contains 16 double springs, 16 RET-TS60/MA2 upper retainers and 16 lower spring seats (SEAT-TS/MA16 or SEAT-TS/MA18E depending on the kit); the original collets are kept.

To find installed height, take the distance between the spring's resting point on the lower seat and the upper retainer while the valve is at rest. A seat pressure holds only for one given distance. As that distance grows, for example once seats are skimmed, the pressure sinks by the stiffness figure, in newtons, for every added millimetre; see the table.

	SUPERTECH
Installed height	36.8 / 34.2 mm
Seat pressure at this height	218 / 311 N

Technical guide

Our brands

SUPERTECH, a Californian firm specialised in competition cylinder heads, has been supplying engine builders for more than three decades. Its springs start as chrome-silicon-vanadium wire, then every batch goes through one ultrasound check, one X-ray check and a final laser check before dispatch.

How to choose

Strengthening the spring lets the engine be pushed further without losing contact between valve and cam: limiter raised, camshaft with more lift, turbo blowing harder. At the seat the kits give 218 N at 36.8 mm and 311 N at 34.2 mm (table above). The only condition: a camshaft lift that stays under the 12.9 mm allowed by the kit.

Criterion

Key point

Choosing the pressure

49 and 70 lbs are worth 218 and 311 N at the seat, each measured at its own installed height. To decide, look at what the camshaft lifts, how far you want to rev and whether the engine is boosted: each increase calls for more load, never beyond the kit's maximum lift. Choosing the strongest load is no goal: it must suit the engine, otherwise the cam lobes wear prematurely. A compromise is needed between top-end stability and gentle treatment of the valvetrain.

Single or double spring

In this kit each valve gets two nested springs, which share the effort and steady one another. A single spring, with one coil, would sit closer to the standard fitment. Both retainers and spring seats ship with every kit.

When reinforced springs become necessary

Camshaft lift above the standard figure
Limiter you wish to raise
Boost raised above the factory level
Head rebuilt for the circuit or rally
Sagging springs, valves bouncing near the limiter

Compatible vehicles

Model	Engine code	Power	Years
MX-5 I (NA) 1.6	B6ZE	106 hp	1989-1993
MX-5 I (NA) 1.6 (NA6C)	B6ZE / B64F	115 hp	1990-1994
MX-5 I (NA) 1.6 (NA6C)	8AN1	90 hp	1995-1998
MX-5 I (NA) 1.6 Turbo	B6GP	150 hp	1990-1992
MX-5 II (NB) 1.6 (NB6C)	B6ZE	120-125 hp	1998-2005
MX-5 II (NB) 1.6 16V (NB6C)	B6MC / B6MU	110 hp	1998-2005