Exhaust valve thermal gradient 2

[Cr250r]

Hi all
I was wondering if anyone could help , I need the average temperature gradient (in an Air cooled gasoline Engine) of the Exhaust valve

Hope some one can steer me onto the right path

Kind regards Stephen

 

[dicer]

It depends if it is a sodium cooled stem or not.
It can run as much as 1150 F at the face area, and 1450 towards the center with out. And with sodium 1150 at face, and 1100 at the center. This in an aircraft engine.

 

[Cr250r]

Thanks , whats about the gradient as we travel up the stem ?

Sodium is fine

Its very difficult to find such info on the internet, I would have though this one would have been easy to find !!!!

Thanks very valuable post

Kind Regards Stephen

 

[Lou Scannon]

There is an excellent SAE paper covering development of the Pratt & Whitney R4360 (air cooled gasoline engine), written around 1950, that documents exhaust valve temperatures, among other things. You can probably purchase the paper at sae.org.

 

[dicer]

It tapers off in a fairly straight line to approx 800 about 1/2 to 2/3rds up the stem from the the valve head.
And I suppose there are some variables to that. Such as guide to stem clearances etc.

 

[amirfarzad]

I think it depends on the design of the guid and valve train as well as tolerences on valve stem and valve guid. but on the end of the stem it should be about 100 degrees more than intake one.