I am running over 100 cubic inches. Should I install two KrankVents, one at the head breather ports and one at the crank case breather?

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I am running over 100 cubic inches. Should I install two KrankVents, one at the head breather ports and one at the crank case breather?

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A7. No, connecting KrankVents to the crank case AND head breather ports is NEVER required. The reason is that once the pistons move down and expel the crank case air, the KrankVent valve closes as soon as the pistons start upward. From that point on, only high pressure crank case pulses escapes through the KrankVent, so it does not have to have a large volume capacity. This assumes that you have a real “tight” engine that does not let air in, right? If you can, hook up a vacuum pump to the timing inspection hole and, with the engine off, listen for vacuum leaks. You might be surprised! If you have both breather options available, block off the head breather ports and only use the crank case breather! After all, thats where the pressure is generated!