When I got the car,it had a BOV installed.....it is doing my head in BTW.... bit old for that sort of thing.....lol Just tried to replace it with a Baileys re-cric which was also supplied with the car and it will take a bit more work that I thought to get it out....no worries though. On top of the BOV,there is a bolt and locking but.....do I screw it in or out to quiten it down a tad ? Thanks, Paul