Rocker box/ valve Cover breather.

[Gmg31]

My rocker box still kicks out quite a lot of oil. About 1pint per 500 miles. You can see I’ve vented it to a catch pot so it’s no big deal. But in my pile of unused parts I found this grey vent with a mesh filter inside.  I’m guessing if I fitted it more of the oil would get trapped and drip back down into the cover.  Unfortunately it’s very rusty inside and I’m not planning to use it. Has anyone seen this before or knows where to get a new one

[Pfreen]

It kind of looks like the attached photo, which is a flame trap for the breather on a TR6.  The photo is from Moss Motors.

[Certified Lotus]

You really shouldn’t vent the valve cover direct to catch can without a baffle. All your doing is taking oil from the top of the head and moving it to a catch can. The best solution is to weld a diverter plate inside the valve cover in the location you are venting from.

[Gmg31]

Do you mean blocking it entirely? Wouldn’t there be a build up of pressure?  I am confused by how much pressure there seems to be at the top of the motor. There’s no back pressure evident from the dip stick but it seems quite strong from the rocker box. All the valves have re seated.

[BDA]

I think what Certified is saying is you need a baffle that makes the oil go around it before it goes to your catch can.

[Certified Lotus]

Correct BDA. On my Lotus Exige S track cars I built a tube that ran across the top of the valve cover with two inlets and at the end of the tube two outlets to the catch can. The tube was filled with a course mesh to catch the oil so by the time it got to the catch can outlet hose it was primarily fumes (the inlets also acted as a return to the valve cover). More importantly, the inside of these valve covers had a baffle plate (diverter) mounted in it. The ports (outlets) were drilled and welded in place above the baffle plate so oil woul not directly flow into the catch can. The wire mesh in the tube was to catch any oil droplets and allow for return back to the engine.

Here is a photo:

[Gmg31]

Updates done, time will tell if it reduces the amount of oil leaving the rocker box.