Cooling System Mods

[vex]

Originally Posted by classicauto

Didn't think about fusing them barry, but I suppose a tack on each corner wouldn't hurt.....just don't want to warp anything.

I'd imagine though, that a press/interferance fit would still have heat transfer through the contacting areas - but correct me if I'm wrong.


__________________________________________________ ______________
I'm getting ready to set this up here though.........and just wanted to pose the question to you guys on whether or not you think the AL used for the housings is anything super special? (in the areas we're talking about adding to)

Reason being, is it was brought up in a discusssion I had recently that some of the sheet AL I have around the shop, may expand at a higher rate then a cast aluminum part.......if this is the case, it would risky to do what I'm proposing if the piece expands too far and creates more problems then it fixes. If it does pose a problem - what grade of AL should I be looking to use?

Thoughts?

You'd have to look at the metallurgy book to get the specifics of expansion rates for the cast and cold formed aluminum. I don't think it's anything significantly special as they are cast, and the different aluminum alloys would require more time and facilities than a mass produced cast would.

Also the difference in temperatures isn't going to significantly deform the material to cause interference/failure of the housing.

Using this list from Mechanics of Materials (5th Edition) we have:

Aluminum: Alloy 1100-H14 (99% Al)
Coefficient of Thermal Expansion (10^-6/F):13.1
" " " " (10^-6/C):23.6
Aluminum: Alloy 2014-T6
Coefficient of Thermal Expansion (10^-6/F):12.8
" " " " (10^-6/C):23.0

Aluminum: Alloy 2024-T4
Coefficient of Thermal Expansion (10^-6/F):12.9
" " " " (10^-6/C):23.2

Aluminum: Alloy 5456-H116
Coefficient of Thermal Expansion (10^-6/F):13.3
" " " " (10^-6/C):23.9

Others have similar Coefficients as the ones listed, so we can use it from there.

We'd need to know specifics about the dimensions of the piece being inserted, but looking at the formula of Alpha x DeltaT we would get (say for reference a Delta T= 167F(operating temperature)-75F(room temperature of the measured piece)=92F)
Biggest heat Coefficient of Aluminum Alloy is 5456-H116=13.3 x 10^-6 /F
Plug and chug we get EpsilonT=.001224
Multiple that number by the length of the piece (lets say .5 in) we have .000612 in increase in overall length. Now if we assume that the Housing as the just as high Coefficient and look at the piece directly across the O-ring (about 1/8 in estimate for example) we'd have another increase of .000153 in.
That means you'll have no stress or problems with thermal expansion unless you have the two edges of the piece within .000765 in of each other.

This is just a rough math crunch to work out the numbers and give you an idea of how little the thermal expansion is going to run. Since we don't normally see a DeltaT of magnitudes of order higher than this example I think we'd have the same/similar numbers for the actual piece.