Originally posted by diesel des
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Delete head breather and pcv?
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Very basic sketch. Basically block all existing head vents. Block intake manifold point. Modify sump to have a return/breather port at the side near the front as per pictures above. Should be 19mm min. Take a line from there and t into drain line from a proper seperator, a provent unit or a good cyclone style seperator. Not a box stuffed with steel wool or fresh air. That drain should be 12mm at the minimum, aim for 19mm.
Continue out of that t (the hose from the sump drain that has its leg going off to the cyclone drain) into the original crank breather. That requires another t. Ideally upgrade the darliks head (what folk call the original block breather) to a aftermarket one as sold on this site. Again take a 19mm to 25mm line from there upto the intake of the seperator. The vent on the seperator can go to a suitable breather filter if you like the smell of oil in the morning, or back to your main engine intake filter for a sealed smell free mot friendly system.
The idea is to keep the oil lines large in diameter so that the sump cannot build up pressure. Also this encourages the oil to seperate from the gas and return as quickly as possible to the sump where it's needed. Oil lines from the head can encourage oil to stay in the head as the flow of gas into the head trying to get out the head breather opposes the flow of oil to the sump. By blocking the head breather you have whatever leakage past the valve stems and seals pushing the oil back down into the sump on its way out to the sump or block breather.
You want oil in the sump, not the head or breather system. If your tracking the car seriously consider an accusump. You need the 2 breather points, eg original block plus the new sump point so that if one gets blocked with oil for a few seconds the other continues to work. On launch normally the original block breather spits out some oil even with sump plates, so the new sump drain/breather point comes into action. During hard brakeing the front sump breather can get blocked, but the original breather is fine. Fitting large catch cans arnt the answer as you just end up with lots of oil in the catch can and not in your sump. Small drain lines are also useless as the oil needs to drain back faster than it gets into the catch can/seperator.
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https://store.034motorsport.com/catc...-c4-s4-s6.html
This is the 034 kit which isn't ideal for many reasons, but what is good is that cyclone seperator. As you can see the inlet feeds in tangentialy and the outlet dips down in to the body some distance. This causes the oil which is heavier than the gas to strike the outside walls and slow down, run down the outside and collect at the bottom. The gas is light and more nimble, so it turns a few times and goes vertically up and out the top where it can be vented to atmosphere or back to the intake filter.
The supplied drain system is worse than rubbish. I drilled the bottom of the cyclone and fitted a 19mm return. I'm not suggesting you buy the 034 item, but get one made that works on the same principles.
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Similar looking setup from land rover
https://rover.ebay.com/rover/0/0/0?m...2F182017255658
And from BMW
https://rover.ebay.com/rover/0/0/0?m...2F392034404757
Not saying these will fit, as port sizes may be wrong but the principal is correct
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I'm going to test those. Will use two in parallel At least one works very well on a 4.4l V8 N/A engine.
Last edited by Thuppu; 29 August 2018, 18:23.
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