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Posted:
Fri Jun 12, 2009 3:53 pmby jfholm
Ed you have once again created and area of great interest. Congrats.
A couple of questions I have is did you use regular sand like for a sand box for the kids?
And if you go to this link and see the sand cores they use go to photo gallery you will see a young lady working with the sand cores and the sand looks finer and all one color of yellow. Is it a different finer sand? Does it make any difference? I snuck in a third question 
John
Posted:
Fri Jun 12, 2009 4:38 pmby 86rocco1
Pretty much any fine sharp sand can be used. I used mortar sand from a local building supply place, I ran it through a fine sieve to get rid of the large grains, for the main body of the mold, the sand was mixed with bentonite clay so that it would hold a shape and for the core the same sand was mixed with a sodium silicate binder.
There are a few different types and grades of sand used in castings depending on what's being cast and the process being used. And there are a lot of different type of binders that get mixed with the sand at industrial foundries, the colour of the sand in those pictures is probably due to the particular type of binder they've used. When I was about 8 years old, I took a tour of the local GM engine plant where my dad worked, their sand was white and became pink when mixed with the binder to form the molds. Just about the only parts of that tour I can remember clearly are the foundry and the dyno room, coincidentally (or not), almost 40 years later I'm casting stuff and dynoing engines.
Posted:
Fri Jun 12, 2009 5:15 pmby Flash
In the foundry that i work at the sand was bone white. after the chemicals were added the mold came out brown.
after the mold was made, the sand was put in a shaker and reused.
After so many uses, it was put in an oven for several hours.
Came out of the oven bone white again!
They would mix the white with the reclaimed, to cut down on chemical used.
They had one hole shop that make and reclaimed the sand molds. And another that did the shell molds
Have no idea what the chemicals were, ether then they smelled vary bad after the metal was ported into them 
Posted:
Fri Jun 12, 2009 5:47 pmby 86rocco1
The sand I use is very old fashioned basically just stuff they dig out of the ground. It has it's limitations but the nice thing is, no nasty toxic substances, it's virtually odor free and it's reusable without any special processing.
Posted:
Fri Jun 12, 2009 7:22 pmby Tony
Posted:
Fri Jun 12, 2009 7:39 pmby jsa
Posted:
Fri Jun 12, 2009 7:53 pmby Tony
Yes, but there will be no contraction in the liquid phase, the molten aluminium just flows and continues to fill the void until it solidifies at the melting (eutectic) temperature.
As soon as it has gone completely solid, and cools further, then it contracts with tremendous force. I just cannot pin down a figure for this. Everyone says something a bit different.
Posted:
Fri Jun 12, 2009 8:27 pmby slracer
Tony, I would think that the difference MAY be due to the alloying materials added to the "pure" AL. Was your value for a particular alloy or just "aluminum"? Some alloys are listed as "NOT castable" while others are "easy to cast" so that may be part of the differences. Just thinking out loud. -- Doug
Posted:
Fri Jun 12, 2009 8:49 pmby 86rocco1
Posted:
Fri Jun 12, 2009 9:17 pmby Tony
Posted:
Fri Jun 12, 2009 9:27 pmby 86rocco1
Posted:
Mon Jun 22, 2009 2:13 pmby 86rocco1
Here's the manifold on the car, I haven't heard it run myself but I'm told that the throttle response with this manifold is outstanding, that's probably due to the short runners and small plenum.
Posted:
Mon Jun 22, 2009 9:57 pmby coulterracn
That manifold looks awesome on the engine. Looking at the combination I can see why it's responsive. You gave the intake enough length to let the runners exit the plenum and give the intakes a straight shot. You've got about 7 inches of runner length.
Ray
Posted:
Mon Jun 22, 2009 10:45 pmby 86rocco1
My primary focus when designing the manifold was to get a good even exit from the plenum and a straight shot into the head, the runner length was about the shortest that would allow for both.
Posted:
Sun Jul 12, 2009 5:31 pmby Chippy
Well after knowing about this forum for several years, but not doing anything practical towards making a flowbench I finally join up with a view to doing something more positive (just got myself a decent sized workshop).
Then I come across this great thread and wonder if I shouldn't be making a manifold instead! I'm also teaching myself how to make composite panels, so many potentially interesting projects, but so little time!
I thought some of you might like these articles:
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