Well, you must have a very small path to your intake somewhere and it's going to be highly sensitive to a solvent like that but not to air. In the stock configuration the path is simply to small to matter except to volatile solvents. >>Has always bothered me that PRV has no obvious way to vent passenger side of engine. Guess it's supposed to pass through timing chain cover.<<< Thats exactly how it supposed to work. >Simple fact remains: many PRV gaskets and O rings, if not tight, allow test solvents inside combustion chambers. You'll see and smell it in exhaust, so obviously getting in there.<< I don't doubt that for a minute but air and volatile solvents are apples and oranges in their effects. >>Have spent most of my ownership in quest for perfect idle. Has driven me fair to crazy.<< Mine was a mess also but was easily straightened out. Idles perfectly now, hot or cold. And it does so with the valve cover off or the breather removed. (Makes a mess with the cover off though, I wouldn't do it.) All I'm saying is there is a very limited path into the induction system from the rocker covers and therefore, the timing cover. Using carb cleaner to chase leaks will lead you down a false path. Sure, you'll find the leaks and mabe even fix them and thats a good thing but it'll have little or no bearing engine performance, especially at WOT where the delta P is small. In other words, you've been "suck into" believing these leaks are bad by the volatility of the carb cleaner. Now a direct leak into the induction system from say, an intake gasket, is much more of an issue. Technically, any air drawn in is not good but there is not vacuum as you're used to dealing with it under these covers. Even my Turbo Toyota Supra's service manual makes it clear these areas should be leaktight but only for proper crankcase and rocker scavenging, ie; PCV operation since the PCV system does port into the intake. If you want to know for sure how these cover "leaks" affect idle performance the only real test is to port a gas anaylzer into the exhaust stream and see if the mixture changes when they're present. It will change for sure when you spray carb cleaner around the covers as long as some finds that small path to the induction system, even though that same leak as air would have little or no effect. If there were a path large enough to upset the idle it would certainly happen when the oil breather is removed. When dealing with any vacuum system you must always consider where the high and low pressures are and try to visualize the direction the gases will flow and under what conditions. You must also be cognizant of the flow rate and volume involved, not just the pressure. (Although pressure and flow are related to a point.) Yahoo! Groups Sponsor ADVERTISEMENT <http://rd.yahoo.com/M=259538.3793308.5048975.1261774/D=egroupweb/S=170512 6215:HM/A=1712983/R=0/SIG=11u38u3s2/*http://hits.411web.com/cgi-bin/hit?pa ge=1374-105951838331032> click here <http://us.adserver.yahoo.com/l?M=259538.3793308.5048975.1261774/D=egroupm ail/S=:HM/A=1712983/rand=773367665> To unsubscribe from this group, send an email to: DMCForum-unsubscribe@xxxxxxxxxxxxxxx Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service <http://docs.yahoo.com/info/terms/> .
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