'Clean air" heat?, crankcase breathers fouling enginecompartment air Options

[PinetreePorsche]

The first VWs (and Porsches) had dirty-air heat-- the 1950s sealed, 'fresh air' heater-box was a big step forward (and I patched many a Boston-area heater box on split-window vans in my relative youth), well before our Type IV motors came into being. I have a problem, enabling my dual carb-fitted (Webers; the p.o. did it-- it would not be my choice) 2.0 liter to mimic some of these earliest VWs: rapid build-up of dirty deposit on the windshield above the defrost vents and hydrocarbons in the pass. compartment air-- un-noticable in the warm weather, tolerable with the windows open, but a drag- and presumably a health risk- when the windows are up and the heater or esp. the defroster needed. The boxes are like new, and the joints all along the way are all snug. The problem is two different small breathers on the top of the engine, one a couple of inches (center to center) of the oil filler tower, the other about 3 1/2 inches toward the driver from the filler, which is one of three hoses running off a fitting, the other two of which disappear into the sheet metal of the cylinders-- one to each side. Both the short woven- cloth wrapped flexy- tubes coming up from these points are currently capped by what appear to be mini-air filters-- round, well over an inch in diameter and not much taller. Both display wire around their open circumference, possibly hiding other filtering material- can't tell.
SO, my Q's are: Are both these breather-like elements under positive pressure from the crankcase--suggested by the fact that a cleaned engine compartment will be well-bathed in oil after a modest run at near 100 mph-- and more gradually under more relaxed driving? IF so, is there a place on a carbed car for these to disgorge their effluents into a closed loop as in the original FI design. (Or is one positive pressure, the other neg? -which, if so?)
Help me, Obi-wan Kenobi, or anyone else who knows how to channel the hydrocarbon force.

[Air_Cooled_Nut]

The T3 and T4 are very similar engine arrangements so here's my carb'd T3 engine and how I have the breather set up:
(IMG:http://www.icbm.org/erkson/personal/engine-2005.jpg)

The long silver box is an after-market breather (CB Performance) but it is on the stock location. The two black hoses on the sides that disappear towards the front of the engine (top of the picture) go to the valve covers. The excess case pressure is vented to the top of the right carb. I used common, brass barbed fittings from the local Ace hardware store.

As a side note, I no longer have the valve covers vented, I just have the one line going to the carb top. So far, after a summer of hard use, I've experienced no issues whatsoever and valve adjustments are a bit easier (no hose to deal with when removing the valve cover). This is a test against convention after-market designs to see how it affects oil leaks due to case pressure. The idea comes from a certified VW mechanic (old school) whose drag race team didn't use vented valve covers. I've known him long enough to trust him and so far he hasn't steered anybody wrong (Russ Wolfe, GREAT guy!). Just a thought, you might try it?

Get a Haynes shop manual and look at how the stock car did it. I know that later on they had the vented covers but, according to the diagram, air went IN to the cover (not OUT) for better emissions quality. Over-pressure was then vented into the air cleaner. One day I'll tap in a vacuum/pressure gauge and see exactly how it works...