2.0 Crank & Head Venting Issues |
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2.0 Crank & Head Venting Issues |
tjtryon |
Oct 17 2016, 03:56 PM
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#1
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Newbie Group: Members Posts: 20 Joined: 15-June 16 From: Indianapolis Member No.: 20,112 Region Association: None |
Car: 1973 2.0 with dual Webbers
Issue: I have a leak from the drivers side valve cover, and poking around, I know my crank & head venting is not correct, which may be what's causing issues. I wanted to fix this first, before I change the valve cover gasket. I have what I believe is the CB breather box already on the car. It has a hose connected to the oil filler area, one to the fan shroud, and one that is venting to atmosphere. I have a hose port at the base of the carb intake manifold on both sides, that does seem to vent air out. I assume these are the head or valve cover vents, but am not sure. Additionally, nothing in the system seems to pull vaccuum, unless the fan shroud vent does so. I have 3 main questions: What are the hose ports at the base of the carb intakes (front of intake on drivers side, rear of intake on passengers side)? What's the correct routing of the hoses? Where does the system pull a vaccuum? Many thanks in advance! |
HAM Inc |
Oct 19 2016, 06:40 AM
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#2
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Senior Member Group: Members Posts: 846 Joined: 24-July 06 From: Watkinsville,GA Member No.: 6,499 Region Association: None |
Sounds like a leaky valve cover gasket. Warped valve cover, or gasket that wasn't glued into the cover, perhaps?
A leaky valve cover will actually act like a vented head by creating a path to atmospheric pressure, taking oil with it. Remember that these engines have very strong crankcase pulses that range from a negative pressure to a positive pressure with every crank revolution. Those high frequency pressure pulses challenge every seal and gasket exposed to crankcase pressure. It's why racers weld tabs in their valve covers to prevent the gaskets from getting sucked inward. We glued our gaskets to the covers with 3M Weatherstrip adhesive, just like all of my dad's race engines. It's a universal truth with ICE's, put the sump pick-up at the lowest point of the engine, and breath it from the highest point. Head vents just allow another path to the atmosphere and keep oil pooled in the heads. |
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