After placing Iron Pipes they will sometimes spontaneously (and incessantly) change their 'out,' direction both visually and in function.

That is to say, I place the iron valve pipe, set its direction with a wrench, only to step back and watch the direction change perhaps as frequently as the block tick.

I am running Minecraft 1.6.4 and running buildcraft-A-1.6.4-4.2.1.jar.

You don't have any redstone that could be triggering this behaviour do you? I believe redstone signals can change the direction of iron pipes

1. I don't believe 1.6.4 is supported anymore.

2. Do not open an issue if you're not planning to fix it, intead open a thread on http://mod-buildcraft.com/forums/index.php?board=2.0

Why did I ever decide to install Chrome Beta...they broke the # links (no editing, previewing...)
What I meant for #2 was:
https://github.com/BuildCraft/BuildCraft#reporting-issues
Specifically,

Do not open an issue if you're not planning to fix it, intead open a thread on http://mod-buildcraft.com/forums/index.php?board=2.0

I think this issue is a typical user help topic and not a technical BuildCraft issue so the right arena is the forum. One thing I notice is that you have 4.2.1 and not 4.2.2. Try to update.

@50Wliu We must still support older versions of BC as best as we can. Especially this early. Bug fixing is a different matter.

Another thing I just saw is that you call the pipe and Iron valve pipe. There is no Iron Valve pipe in BuildCraft. This might just be you not using the correct name, but make sure the pipe is actually a part of BuildCraft.

In response to simon816: there are no redstone signals anywhere near, horizontally or vertically.

In response to 50Wli's comment: I apologize, I didn't understand that we had already moved to 1.7.2, whatwith all the warnings about instability.

In the future, I will post such issues to the correct location, my apologies.