Thread: BOV orientation
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mark houghton mark houghton is offline
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Join Date: Jul 2008
Location: Central Washington State
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Originally Posted by JFairman View Post

The black rings on the top part are orings in the grooves for cosmetics and getting a grip on it to unscrew the top or adjust spring tension.
There's another important oring on the inside to seal the top to the frame even if it is partially unscrewed to lighten spring pressure.

The brass piston in mine is hollow and about 2" long and the majority of the spring is compressed inside it.
The piston doesn't get wider at the vacuum line end so surface area that boost pressure will push against is the same on both sides of the piston but there is a chamber 360 degrees around the sides of the piston just above where it seats so that would improve air flow through it when the piston is off it's seat and the BOV is open.
Internally mine is built exactly the same as yours. I took it all apart the other day to lap the valve seat just because I could. I think I'll be happy with it once installed. Great price at $36 brand new.
Mark H. 1987 930, GP White, Wevo shifter, Borla exhaust, stock everything else. The result of a massive Pelicanite good will fire recovery effort. Truely an open book, ready for the slippery slopes to modification.
Old 12-08-2009, 10:44 AM
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