4.6L V8 - Why are valves on right side brown but left side silver?

[SyberTiger]

I've got the valve covers off and the timing chain cover off and I'm pondering why it is that the right side valves are golden brown color whereas the left side they are still silver color like new. I was thinking it's pretty weird and my concern is that there's something wrong with what I'm seeing. However, using THIS VIDEO as a guide I noted the vehicle being worked (2003 Mountainer) on also exhibits the same discoloration. In THIS POINT in the video you can see the right side is covered in a golden brown film whereas at THIS POINT in the video you can see the left side is shiny silver. This is exactly what I discovered on my engine.

My theory is that either these engines run hotter of the right side or more likely this has to do with the fact that the PCV valve is located on the right side valve cover and it is drawing the hot gases containing gunk to be cycled back for combustion and it is the hot gas gunk causing the discoloration. Below are pics from my engine. What is your explanation as to what is causing this on the 4.6L V8?

 

[Hugh Janus]

Very common. The oiling on the right side is very minimal.

 

[boominXplorer]

I'm pretty sure it's because it's last in line for oil pressure. It's common on all engines for one side to be a little cleaner than the other. On the 4.0 sohc the right/passenger side gets oil first.

I have a great running 5.4 with 150k that looks identical to you pictures. It ran great with no noise before it was pulled from a wrecked truck. I was surprised to see 1 side so clean and one so dirty but it's always the common thing with the modular motors.

 

[SyberTiger]

I determined it's not oil flow or lack thereof that causes this. It's the location of the PCV valve located on the right valve cover and here is why the brownish stain is where it is:

Hot gunky crankcase gases are being redirected to the right side of the engine thus leaving the brownish appearance. The inside of the timing chain cover also indicates this is what is happening as the excess gases in the oil pan would naturally flow towards the PCV valve when it is open. From the pics above you can observed that the brownish stain starts at the bottom of the timing chain cover where it meets the oil pan and flows up and into the right-side valve cover staining the right cam sprocket and the cam ladder cap cluster (and other components) up to around where the PCV valve is located in the valve cover. Beyond the point of the PCV valve location (above the front of the 2nd cam ladder cap cluster) the brown stains diminish quicky with it being silver and unstained towards the firewall.