Seeking knowledge?
Discussion
Can someone educate me how/why the vacuum hose from the offside rocker cover to the plenum on the 2.9 works as is it so important? With just a little leak the car runs rough and when running and you pull it off it stalls instantly. Unable to drive at present so tinkering under the bonnet instead. Engine mounts next.
The pressures inside the cylinder can leak two ways.
Via the pistonrings to the oilsump, and via the valveseals to the 2 rockercovers. These 3 are all interconnected inside the engine.
The overpressure from the leaking gas needs to be bled. Because of the interconnection one take off is enough.
For environmental reasons, this is connected to the engine inlet, so the vapours will recirculate to the cyl's and will hopefully burn.
Too much leakage will create problems. If there are already problems at tickover, it will be worse under engine load.
Mostly it is the valves leaking, which is the cheaper repair.
If you are experimenting with taking the vacuum/breatherhose off, you need to close off the connection at the airintake side.
Watch what comes out of the rockercover via the breatherhose then.
hth Boudewijn
Via the pistonrings to the oilsump, and via the valveseals to the 2 rockercovers. These 3 are all interconnected inside the engine.
The overpressure from the leaking gas needs to be bled. Because of the interconnection one take off is enough.
For environmental reasons, this is connected to the engine inlet, so the vapours will recirculate to the cyl's and will hopefully burn.
Too much leakage will create problems. If there are already problems at tickover, it will be worse under engine load.
Mostly it is the valves leaking, which is the cheaper repair.
If you are experimenting with taking the vacuum/breatherhose off, you need to close off the connection at the airintake side.
Watch what comes out of the rockercover via the breatherhose then.
hth Boudewijn
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