Air cleaner

[Farmall 450 lp]

So today i was bored and i thought it would be a good time to take the valve cover off and check the torque on the head after a rebuild with around 10 hours run time on it. Then to my surprise there was a thin layer of dirt on the head. The only way i thought it could have gotten in was through the valve cover breather. Yet the hose that runs to the valve cover is hooked up and it seemed like all filters were in place. So getting down to the point, on the cover that fits on top of the aircleaner (not the jar kind and almost looks like a mushroom) is there supposed to be a filter/foam in it? Because mine doesnt have one. Also is the valve cover breather tube supposed to be located 5 to 7 inches down from the top of the aircleaner because in that location it has no filtration for the air. If there is supposed to be a filter in the mushroom shaped aircleaner top, what should i use as one?I almost had a cow when i saw dirt under the valve cover and would really appreciate any suggestions or help. Thanks.
 

[Janicholson]

There is not supposed to be suction at that venting system. If blown in dust is getting in I would purchase one of the preclaener systems with jar. There may have been dirt in a connector that you were not aware of, but it is just a guess. Crank case pressure is intended to be relieved through that system, not drawn through it toward the engine. There is a small orifice that is intended to be a restrictor on the flow (usually as a end in a fitting with a 1/8" hole or so). There is also a road draft vent tube with wire mesh screen on the lifter cover. It is vented into air and is also responsible for pressure relief. Were it mine, I would run it with the hose off and feel for suction on the connection. If none, I would put the precleaner on it and go to work. Jim