Quote:
Originally Posted by Christ
I don't like the idea of drawing vacuum from the valve covers, because if you get enough air moving, it could work against the oil flow dropping back into the block, causing oiling issues and changing the center of gravity of the vehicle (allbeit not by much) as a whole, in upright applications.
I'd rather draw the crankcase vacuum from two vents, one at the back end, one at the front end, both at the highest possible point that would provide the largest distance between the vents and the oil. The vacuum ports in the block should have either wet filters or screens on them to help prevent liquid oil flow, or at least help to vaporize whatever does get out, so the catch cans and separators have a better chance of doing their job effectively.
Anyone know how to get/make dual sided seals? So that you can hold oil in and still hold air out?
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Contact a seal manufacturer. This has been done in racing for at least 40 years, I'd say. Probably much, much, much longer. Some people reverse the stock seals. New seals is one of the reasons why it is more practical to hold vacuum to reasonable levels. Don't forget that oil pump, too.
The next issue is pin oiling. As atmosphere is reduced the pattern of ejected oil from the mains and rods reverts to disks in 3-space. The pins are typically oiled by the scraper rings from areas of the bore that are orthogonal to these disks. Et voila -- pin oiling problems. There are simple ways to address this but it is yet another thing in an increasingly long list. Heck, why not shift the pistons bores over like in the Honda engine to increase the efficiency while you're in there.