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Message: <blockquote data-quote="shovel" data-source="post: 1588407" data-attributes="member: 29855">Next topic here is valve covers, PCV, crankcase vent etc..There's a bit of a puzzle here and probably a dozen different ways to solve it, here's the challenge:PCV is a loop.  The engine has a positive crankcase ventilation valve connected between the crankcase and the high vacuum of the intake manifold - this high vacuum is modulated with a valve that limits flow under very high vacuum (idle, decel)  and allows quite a bit of positive flow under medium vacuum like mid-throttle cruise and then limits flow again under very low vacuum (wide open throttle) to avoid possibly running lean under heavy throttle.   The valve is a pretty simple tool but they can get stuck and they also represent a mechanical doodad controlled by physics, air density, temperature, gack buildup, etc and completely outside the control of the ECU.   Closed loop operation largely makes up for their capricious nature as long as they behave well under idle.   What might not be obvious is that different PCV valves have different spring calibrations and when you buy a random PCV valve it could just sit wide open while you're at idle and that makes it a lot harder for your IAC valve to do its job. The other side of the PCV loop is a higher volume, unobstructed vent that ideally goes to the intake tract between the filter and the throttle body.  On a stock SN95 that's the little question mark shaped hose between the oil filler neck and the air intake tube.  That allows a the light but constant vacuum generated by the engine against the restriction of the air filter media to draw combustion gases out of the crankcase even when the PCV ain't PCV'ing, but it also means that if the high vacuum PCV is really pulling a lot of air through there's a ready source of filtered fresh air to get sucked into the crankcase.  The movement of air through this tube could go either way at different loads and RPM's. So ideally I want both of those things to still work as intended but the carb style intake manifold doesn't have a PCV channel into the lifter valley like the stock SN95 lower manifold does.   That means the PCV has to be mounted in a valve cover like older cars.  The SN95 valve covers are super low profile to clear the big MPFI manifold so there isn't room to install a PCV bung and baffle above the rockers and without a baffle it would just suck up oil spray like a straw.   The new intake manifold allows for tall valve covers with bungs and baffles but the location of the alternator prevents tall valve covers from fitting on the passenger side.   It's possible to run a tall valve cover on the driver side and the stock valve cover on the passenger side to solve that dilemma but c'mon would anyone really do that?For my particular application this wasn't a big deal because I was going electric with the power steering and air conditioner and I eliminated the secondary air pump.   That meant I need a big alternator for all that electrical current,  or at minimum it's good to give a stock sized high current alternator as much room as possible to dissipate heat instead of cozying up against the cylinder head.  So I relocated the alternator down on the passenger side and just stuck a couple tall valve covers on.</blockquote>