Well the Photobucket pics are back up for the time being--until I exceed by bandwidth again!
I'll try to get them all moved before that happens again, but for now, let's pick up where I left off and talk about crankcase ventilation on the V-32 engine!
Now for those who aren't familiar with why the crankcase needs to be ventilated, the simple explanation is this: all piston engines generate blow-by, which is when hot gases in the combustion chamber escape past the piston rings and enter the crankcase (not to be confused with valve blow-by, which is a whole nother issue). In severe cases, where the piston rings and cylinder walls are badly worn, you'll also get fuel and other contaminates entering the crankcase and contaminating the oil. All of this can ultimately lead to the destruction of the piston and the cylinder itself, but for this post, we'll just stick to the combustion gases! Unless these gases are vented, they will build up inside the crankcase and cause oil leaks (that pressure has to go somewhere!), as well as affecting the overall performance of the engine. Over time, you'll also get a nasty buildup of oil sludge as well.
The solution that the designers of the V-32 engine came up with for ventilating the crankcase was pretty ingenious, and I'll quote it directly from the manual:
"The system when operating, ventilates the interior of the engine and maintains a negative pressure in the crankcase. When the engine is operating, cooling air flowing through the scroll creates a negative pressure in the breather tube which opens the breather valve in the oil filler neck exposing the crankcase to the negative pressure. At the time this negative pressure is induced in the crankcase, the ventilating valves on either side of the crankcase which are controlled by calibrated springs, permit air flow originating at the rocker box vents, to pass through the rocker box vent hose to the crankcase. Sufficient air flows to ventilate the engine interior, but is so controlled that a constant negative pressure is maintained. It is when this negative pressure is destroyed, usually through malfunction of the valves, that positive pressure is built up and severe oil leakage develops at various places in the engine."
Now let's take a look at the various components of the system.
The breather tube:
Here's where the breather tube connects to the scroll.
And the one-way valve on the oil filler neck:
Here we can see the rocker box cover vents and hose, and another sophisticated graphic of the airflow
And finally a "ventilator valve" (one-way valve).
In the next update, just as soon as I can sit down to go through all the pics, we're
really going to get our hands dirty and dig into this engine! Well,
I'm going to get
my hands dirty, while ya'll just sit back and watch
Stay tuned!
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All I can say is wow.. Very interesting thread about the B-29 APU. Thank You for sharing this...
