Exhaust Valves

[physicsfool]

Alright chaps,

With the sodium filled valves currently extinct from VW i have been thinking about alternatives. Sodium filled valves are a good way of converting heat through conduction, however it wont occur until the sodium has melted and passes over both surfaces. The melting point of sodium is roughly 100*C, and my running temperature never seems to surpass 80*C. So are the sodium filled valves aimed at turbos/track cars?

Anyone comments on engine temperatures for turbos or track orientated cars?

I have found exhaust valves made by 'Intervalve' which state a Bi-metal, i am currently running a set of inlet valves from them, but will be inquiring as to which metals they are and their heat rating.

Just interested to hear of any valve alternatives..

[Yoof]

Your coolant might not be exceeding 80'C.... but your exhaust gas temp definitely is!

[paulpolo]

Not an alternative but I believe these are the sodium filled exhaust valves for the PY engine

http://shop.volkswagen-classic-parts.de/vwcp/Polo-Derby/Polo-II-2F/Antrieb/Motor/Auslassventil.html

[physicsfool]

Your coolant might not be exceeding 80'C.... but your exhaust gas temp definitely is!

Ay, but interested in temperatures reached by tuned/turbo's engines that will be running hotter!

[physicsfool]

Not an alternative but I believe these are the sodium filled exhaust valves for the PY engine

http://shop.volkswagen-classic-parts.de/vwcp/Polo-Derby/Polo-II-2F/Antrieb/Motor/Auslassventil.html

Yup, these are top dolla, I wonder if it would be more economical to go straight to the manufacturer in this case 'intervalve' and custom make a hollow sodium filled valve, with the g40 spec! I will have a chat with the local engineering company that got me a set of inlet valves last time.

[Yoof]

Your coolant might not be exceeding 80'C.... but your exhaust gas temp definitely is!

Ay, but interested in temperatures reached by tuned/turbo's engines that will be running hotter!

Not always- depends how much fuel is used.

£20/valve is a fair price, I doubt you'd get a low volume run any cheaper. Also you've got all the design effort, testing, validation etc. Better to stump up £80 and know they're right.

Pete