Ferrari Valve Guides

bmetcalf

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On a TV show here How It's Made, they showed dipping the guides in liquid hydrogen in an open vessel to shrink them into the heads. I find it hard to believe it is really not nitrogen being used. The 100F lower boiling point and the danger of hydrogen fumes convinces me. The room temperature interference fit would be interesting. Apparently no lock rings required for them!
 

Magnetoman

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On a TV show here How It's Made, they showed dipping the guides in liquid hydrogen in an open vessel to shrink them into the heads. I find it hard to believe it is really not nitrogen being used.
Don't believe everything (or anything...) you see on TV. In addition to its Hindenberg qualities, hydrogen costs more to liquify because it's colder (and less abundant) and has only ~20% the latent heat of vaporization of liquid nitrogen, i.e. it would boil off ~5x more cc/liters/gallons for every part that was cooled using it rather than nitrogen.

Depending on the material roughly 90% of the contraction that would take place if cooled with liquid hydrogen happens by liquid nitrogen temperature, leaving very little additional to be gained by cooling further than that. Score: Liquid Nitrogen 1, TV 0
 

BigEd

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On a TV show here How It's Made, they showed dipping the guides in liquid hydrogen in an open vessel to shrink them into the heads. I find it hard to believe it is really not nitrogen being used. The 100F lower boiling point and the danger of hydrogen fumes convinces me. The room temperature interference fit would be interesting. Apparently no lock rings required for them!
The "How It's Made" is usually quite interesting but I think it most likely when they said hydrogen they should have said nitrogen.
Not to be too hard on the presenters and script writers they are usually very technically minded. Think about the number of times TV producers can't even get the right exhaust sound when a motorcycle plays a part in their programme.:eek:
 

vibrac

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TV Producers~
As I remarked here before you notice their ineptitude when the subject is something you have detailed knowledge of. The big worry is that such ignorance must perforce extend to all subjects....
For me examples of their most idiotic activities are putting reporters outside of buildings where something has occurred, to stand in traffic and inclement weather and ask them to shout some banalities at the camera!, An activity that could easily be done better and cheaper in a studio. Or to fill the screen with pictures of childrens feet while discussing education statistics when one graph on the screen could help to say it all.
No wonder the BBC is running out of money
 

nkt267

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Think about the number of times TV producers can't even get the right exhaust sound when a motorcycle plays a part in their programme
Or calling a Comet a Black Shadow( American Pickers)
 

timetraveller

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You might think it is bad on the technical details concerning engineering and the like. When it comes to both astronomy and continental drift they clearly have arts graduates doing the writing and on occasions shaved monkeys doing the presenting. Help.
 
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