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-   -   Thermal Expansion Coefficients (https://www.s2ki.com/forums/s2000-naturally-aspirated-forum-213/thermal-expansion-coefficients-1191975/)

JagoBlitz 02-20-2019 11:58 AM

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

rocketstarter 05-05-2019 08:56 AM

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

JagoBlitz 05-05-2019 09:54 AM

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

rocketstarter 05-05-2019 07:56 PM

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.

HawkeyeGeoff 05-06-2019 09:21 PM


Originally Posted by rocketstarter (Post 24598653)
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.

smee123 05-31-2019 07:58 AM


Originally Posted by JagoBlitz (Post 24568716)
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


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

JagoBlitz 05-31-2019 08:15 AM


Originally Posted by smee123 (Post 24607676)
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.

smee123 05-31-2019 09:06 AM


Originally Posted by JagoBlitz (Post 24607685)
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.

ZDan 05-31-2019 06:47 PM


Originally Posted by smee123 (Post 24607707)
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...


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