Thermal Expansion Coefficients
 

Hi,

does anybody know the Thermal Expansion Coefficients of the Cylinder Head and the Intake/Exhaust Valves?
I am considering using custom-made valve guides and I want to determine the correct dimensions.
Thank you for your help.

JagoBlitz

Look in your solid mechanics textbook, I don't understand why you're asking this in a thread

If you can tell me the exact alloys which Honda used, I will look it up.

Send a sample to a materials lab and they can perform EDS on it and give you the exact composition of the alloy, maybe they even have a match in their library.

Or look in your textbook and take an average for 2011 through 7075 since they're all a few tenths apart from each other. The maximum delta is .08x10^-6/degC, in this order of magnitude you are not going to see an appreciable deformation regardless which value you use.

Or just eyeball the table and use 23.4x10^-6/degC.

For OEM valves you will have to perform EDS. Honda is on top of their materials game and their engineering team is annoyingly hardcore and meticulous, I highly doubt you will find accurate information of what exact alloy was used.

Yeah you'd basically have to know a Honda engineer that worked on cyl heads / metallurgy from the 90's to really figure this out unless you wanted to do some destructive testing and pay a bunch of money.

What is the reasoning for the custom made valve guides? Also, what is wrong with the factory ones?

Well, I would like to switch to copper/bronze valve guides to reduce wear and increase the lifetime.
Unfortunately, most companies do not specify which alloy they use for their bronze valve guides and that bothers me a lot.

It's like saying "steel". Is it low strength? High strength? Stainless steel? There are so many alloys with different properties.
It's the same with "bronze"... I just want to know what I am buying.

Probably a relevant question for the valve manufacturer, assuming you are going aftermarket. Also to note, some manufacturers offer a hollow stem valve, which will throw a wrench in your thermal coef calcs.

Hollow-stem valve will expand/contract at the same rate as solid...