Valve cover breather

Zach Baumann

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Doing a 3v rebuild and I noticed a bunch of metal shavings in my catch can when disassembling the engine. What are the issues with removing the tube from the valve covers to the intake/manifold and installing valve cover breathers? Will it require additional tuning?
 
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Doing a 3v rebuild and I noticed a bunch of metal shavings in my catch can when disassembling the engine. What are the issues with removing the tube from the valve covers to the intake/manifold and installing valve cover breathers? Will it require additional tuning?
metal in the can? you sure its not the metal from your top end? as to the question, no you dont need additional tuning, i run breathers on my covers as well as on oil fill cap - i did not remove the pcv from the valve cover. The only downside is that the oil cap filter will get milky a bit if rain hits it Oil+water but thats about it just clean it of after rainy day if you have hood vents
 

Zach Baumann

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metal in the can? you sure its not the metal from your top end? as to the question, no you dont need additional tuning, i run breathers on my covers as well as on oil fill cap - i did not remove the pcv from the valve cover. The only downside is that the oil cap filter will get milky a bit if rain hits it Oil+water but thats about it just clean it of after rainy day if you have hood vents
Yeah I think the metal is from the baffle in the catch can itself. I found a lot of scoring in the cam journals but it was there when I rebuilt the top end 2 years ago. But now I have a whole new top end and bottom end except for the block and I don’t wanna ruin it with the catch can just to be safe.
Do you just block off the holes on the intake and manifold then after the breathers are installed?
 
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GriffX

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As Andrey already mention, the oil is cleaner and the slight vacuum on the engine helps to reduce air pump losses. The piston going down pumps air to the piston going up. Less air, less resistance. And the vacuum evaporates fuel and water in the oil faster.
 
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Yeah I think the metal is from the baffle in the catch can itself. I found a lot of scoring in the cam journals but it was there when I rebuilt the top end 2 years ago. But now I have a whole new top end and bottom end except for the block and I don’t wanna ruin it with the catch can just to be safe.
Do you just block off the holes on the intake and manifold then after the breathers are installed?

yeah i capped intake and the hole in the intake filter pipe
 

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