Yesterday I was removing the engine and valve covers from Project 26 to send off to the powder coater for a fresh texture finish. The painter needs the parts disassembled, which includes removing the cover and baffle to the oil/air separator atop the rear valve cover.
Honda refers to this assembly as the "breather," and its function is to separate oil droplets from the positive crankcase ventilation (PCV) system. As the running engine develops pressure pulses in the crankshaft area, those pulses, along with the oily vapor they carry, must be vented. In the bad old days, they were simply shunted into the atmosphere, but back in the 60's the PCV concept was incorporated into our cars as one of the first forms of environmental emissions regulation. The vapors are given an escape route into a cylinder head, and vented from there to the airbox, mixing with the intake air and drawn back into the engine to be burned up during combustion.
Somewhere along the line the oil droplets need to be separated to prevent oil pooling in the airbox or wetting/clogging the air filter. That's the function of this simple baffle device. By forcing the PCV pulses to "turn corners" through the baffle chambers, the droplets fall out of suspension and drain back into the cylinder head and downward to the sump. It may be a simple concept, but a closer look at the casting shows a lot of engineering involved here — no moving parts, with the thin metal baffle plate even serving as its own gasket. Simple, elegant, effective.
(click on an image to enlarge)
Honda refers to this assembly as the "breather," and its function is to separate oil droplets from the positive crankcase ventilation (PCV) system. As the running engine develops pressure pulses in the crankshaft area, those pulses, along with the oily vapor they carry, must be vented. In the bad old days, they were simply shunted into the atmosphere, but back in the 60's the PCV concept was incorporated into our cars as one of the first forms of environmental emissions regulation. The vapors are given an escape route into a cylinder head, and vented from there to the airbox, mixing with the intake air and drawn back into the engine to be burned up during combustion.
Somewhere along the line the oil droplets need to be separated to prevent oil pooling in the airbox or wetting/clogging the air filter. That's the function of this simple baffle device. By forcing the PCV pulses to "turn corners" through the baffle chambers, the droplets fall out of suspension and drain back into the cylinder head and downward to the sump. It may be a simple concept, but a closer look at the casting shows a lot of engineering involved here — no moving parts, with the thin metal baffle plate even serving as its own gasket. Simple, elegant, effective.
(click on an image to enlarge)
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