Reinforced exhaust valves Mazda MX-5 1.6 B6
Set of 8 reinforced exhaust valves for the Mazda MX-5 1.6 B6.
- Brand: SUPERTECH
- Engines: B6ZE, B64F, B6GP, 8AN1, B6MC, B6MU (MX-5 NA and NB 1.6)
- Dimensions: 26.2 mm or 27.2 mm head, 5.94 mm stem
- Material: black nitrided stainless steel
Mazda engines covered
The B6 is Mazda's 1.6 litre, twin overhead camshaft, 16-valve four-cylinder that powers the first generation MX-5 (NA) and then the 1.6 version of the second (NB), from 1989 to 2005.
It carries 8 exhaust valves, two per cylinder, with a 5.94 mm stem; they release the burnt gases on every cycle and take the highest heat in the valvetrain.
SUPERTECH reinforced exhaust valves
On a naturally aspirated engine, the metal of an exhaust valve head reaches 760 to 870 °C, and 1,000 °C or more when turbocharged. The head cools for about 75 % through the seat and for nearly 20 % through the guide. An EV8 family steel falls from 550 MPa at 600 °C to 300 MPa at 800 °C: the head can then overheat, fatigue, distort and no longer seal.
SUPERTECH makes these valves in high temperature stainless steel, with a black nitrided surface that hardens the stem and limits wear in the guide.
The MAEVN-1102-8 keeps the stem and length of the MAEVN-1100-8; only its head grows from 26.2 to 27.2 mm. The burnt gases leave faster, the chamber empties better and the engine gains power; the exhaust seats are machined to the new size.
Exhaust valve technical specifications
| Part number | Brand | Size | Head Ø | Stem Ø | Length | Grooves | Material |
|---|---|---|---|---|---|---|---|
| MAEVN-1100-8 | SUPERTECH | Standard | 26.2 mm | 5.94 mm | 105.35 mm | Black nitrided stainless steel | |
| MAEVN-1102-8 | SUPERTECH | +1 mm | 27.2 mm | 5.94 mm | 105.35 mm | Black nitrided stainless steel |
The MAEVN-1100-8 keeps the original head size; the MAEVN-1102-8 is the version with a head enlarged by 1 mm.
Valve fitting
| Part | Mazda original | Reinforced |
|---|---|---|
| Collets | ||
| Valve stem seals | ||
| Valve guide |
Check that the original collets sit properly in the groove of the new valves before releasing the springs.
The 5.94 mm stem runs in the cylinder head guides: measure their clearance before reassembly and replace worn guides.
The exhaust seats are recut during the rebuild; with the MAEVN-1102-8 they are machined to the 27.2 mm head diameter.
Technical guide
Our brand
 |
SUPERTECH, an American maker of valvetrain parts for racing, offers two black nitrided stainless steel exhaust valves for the B6, in standard size and with a head enlarged by 1 mm. |
How to choose
The two versions only differ by their head:
| Criterion | Option 1 | Option 2 |
|---|---|---|
| Size | MAEVN-1100-8 26.2 mm head, standard size. |
MAEVN-1102-8 27.2 mm head (+1 mm), seats to be machined. |
When reinforced valves become necessary
- Higher lift camshafts
- Fitting a turbo or a supercharger
- Track or hill climb use
- Cylinder head rebuild with tired exhaust valves
Vehicle compatibility
| 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 Turbo | B6GP | 150 hp | 1990-1992 |
| MX-5 I (NA) 1.6 (NA6C) | 8AN1 | 90 hp | 1995-1998 |
| MX-5 II (NB) 1.6 (NB6C) | B6ZE | 125 hp | 1998-2005 |
| MX-5 II (NB) 1.6 (NB6C) | B6ZE | 120 hp | 1998-2005 |
| MX-5 II (NB) 1.6 16V (NB6C) | B6MC / B6MU | 110 hp | 1998-2005 |
OEM part number (exhaust valve):
Don't forget the inlet valves
During the B6 cylinder head rebuild, also replace the inlet valves and the valve stem seals.
| Inlet valves Mazda MX-5 B6 1.6 → |
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Brand
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ReferenceMAEVN-1100-8
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