Valve clearances

[mistersouthpaw]

Oh for sure they were horrible machines to keep running lol but omg did they ever feel fast.

Friend of mine who has a few years on me said the exact same thing when he was telling me about his he had back in the day

 

[GreyGhost]

Engines don't get hot enough to expand steel pushrods. Aluminum expands at much lower temps so you need more clearance with Aluminum .

Huh? There is no magic temperature you have to reach. It is just based on delta T. An engine is hotter after running than after sitting, therefore things expand.

 

[Mad Mike]

Huh? There is no magic temperature you have to reach. It is just based on delta T. An engine is hotter after running than after sitting, therefore things expand.

The linear thermal expansion coefficient is the ratio change in length per degree temperature to length. From 20-300c, Aluminum expands in length at at 20*10-6mm per degree C, where steel rods expands at 1/2 that rate, and Chrome-moly 1/4 that rate.

 

[Trials]

How about Titanium, it has a very low coefficient of thermal expansion.

 

[Mad Mike]

How about Titanium, it has a very low coefficient of thermal expansion.

Titanium and steel are almost identical. Here's a list of common metals: Thermal Expansion of Metals

 

[Trials]

Titanium and steel are almost identical. Here's a list of common metals: Thermal Expansion of Metals

4.8 is a lower number then any of the steels, plus a significantly lighter material, I'm liking the Titanium for a fast moving part.
& almost doesn't cut it unless you are playing horseshoes

 

[Brian P]

don't confuse the C and F numbers ... I'm using the C numbers.

Titanium 8.64, mild steel 10.6, various stainless steels are anywhere between 9 and 17, carbon steel 14, grey cast iron 10.4, various aluminum alloys are clustered tightly around 23-24.