This tip comes to us from an interview we conducted with engine builder Brad Hibbard from Race-1: "We constantly see engines with non-shielded breathers, dirty breathers and breathers that are shielded, but the shield is positioned wrong. Evacuating air from the crankcase is critical to ring seal and power. The valve cover breathers are the only source of evacuation and need to be properly maintained. Keep in mind it is air out, NOT in, and the shield should be used and positioned so that the fan cannot induce air into the breather."
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