Paul (Notts)
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| posted on 21/8/08 at 07:03 PM |
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PCV on a Rover V8
Positive Crankcase Ventilation…
Have been running my rover V8 with a breather filter on top of the flame trap and the small filter on the other rocker cover, This means that any blow
by gasses can escape via the breather filter.
Having looked at the EFI set up it sucks air out of the flame trap creating a low pressure in side the crank case. Air is then sucked into the other
rocker cover via the small filter. This removes all the blow by gasses and, according to some literature, helps to prevent oil loss via the valley
gasket and other oil seals.
Today I have altered my set up so that I have a PCV valve fitted to the top of the flame trap and this then connects to the pcv port on my webber
500.
Mine only concern is that I may end up sucking oil mist of of the crank case as the pressure drop inside the crank case seem large. When the engine is
switched of you can hear air being pulled in via the other small filter for several seconds.
Now for the question - What have other people done about PCV on a V8 and any thoughts on the above set up.
Paul
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Paradoxia0
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| posted on 21/8/08 at 07:11 PM |
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I have the flame trap (and the oil filler actually) going into an oil catch tank which is vented via a small filter.
The small outlet also has a small filter on it.
Mark
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Dave J
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| posted on 21/8/08 at 07:52 PM |
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I have a breather pipe from nearside rocker cover to lower side of air filter and PCV valve fitted to offside rocker cover (made a threaded fitting to
replace the oil filler cap, PCV valve fits in top)which vents to the lower part of the Edelbrock 500 carb where there is a pipe specifically for this
purpose. Seems to work ok.
Cheers
Dave
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robinj66
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| posted on 21/8/08 at 09:19 PM |
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Paul
I have mine set up as yours - PCV from flame trap to pcv port on carb and small filter on the other rocker. It works fine until the filter gets
blocked - take it off and clean/replace it.
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mark chandler
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| posted on 21/8/08 at 09:28 PM |
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Are you sure air is being pulled in ?
I had a purchased a classic rangerover with a serious oil leak, the pipe to the plenum became blocked, when switched off the hissing was air escaping!
The pressure caused the tin plate above the rockers to become warped.
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kenton
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| posted on 21/8/08 at 09:50 PM |
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I have a hose from the offside rocker cover to the inlet plenum. The nearside rocker is vented by a v small filter (standard setup)
pic..Forum Code:
 
Twin plenum intake
kenton
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02GF74
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| posted on 22/8/08 at 06:47 AM |
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dunno about efi but my block has vent at the back. there would be a pipe to the air filter so that air is drawn into the block. and there are two
flame traps that go to each rocker cover to vent blow by gases to the carbs for them to burn off.
in other word, the v8 is a fully breathing animal; draws air in and expells it.
now I think on later engiines (EFI) the bock breather was deleted. I don't know how the flame traps are connected on EFI as I have carb angine
and am about 1,149 miles away from my haynes manuals.
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mr henderson
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| posted on 22/8/08 at 07:42 AM |
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The last two posters haven't mentioned a PCV valve though they may well have them. The point of these valves is to restrict the amount of inlet
manifold vacuum that is presented to the block.
When I first had a V8 with weber/edelbrock set up I didn't use a PCV valve to start with, and the whole engine whistled at idle (high
vacuum).
John
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mark chandler
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| posted on 26/8/08 at 09:59 PM |
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Probally because I have never seen a v8 rover with one, and I have seen quite a few.
Early carb engined ones had a simple air filter that connected to a small tune that came out the back of the push rod valley,
Going a bit later you had a couple of simple mesh filters feeding into the carbs, this disappeared with EFI when you have a basic filter that the
plastic top falls off on one rocker cover and the other has a pipe into the front of the plenum.
Never seen a PCV valve of any shape of form, just wire mesh or cloth type filters.
As the sump is open through the cam valley there is no need to take fumes from low down so no valve required, just vent.
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