I use Bell Hammer Gold on a car's variable exhaust valve when the shaft sticks due to soot. Since it's NA, the exhaust temp is lower than turbo, but is it still out of range for Bell Hammer Gold? Could this cause seizing over time?

Regarding your inquiry about using Bell Hammer Gold on the shaft of a variable exhaust valve, please see the following response.

Bell Hammer Gold is designed for lubricating and rust prevention of metal sliding components, with an expected operating temperature range of ambient temperature to approximately 180–200°C.

As you pointed out, in naturally aspirated (NA) vehicles, external exhaust areas such as the outer muffler or shaft surroundings are less likely to reach extremely high temperatures. Therefore, in short-term or routine use, the likelihood of major issues occurring is considered low.

However, since the shaft of a variable exhaust valve is located near the exhaust flow, temperatures may exceed 200°C depending on driving conditions and heat buildup. In such cases, there is a potential risk that the lubricant may degrade or carbonize due to heat, which could lead to seizing or malfunction over time.

We therefore recommend the following precautions:
- Perform regular reapplication and cleaning

- Frequently inspect for signs of carbon buildup or residue

If you observe carbon deposits or feel uncertain about continued use, we also recommend considering our Bell Hammer Metal Grease, which is more suitable for high-temperature environments.