Question #2: Why does engine moan internally as soon as breather tube >from air filter housing plugged? If passive shouldn't care. It's not passive, see below. You're pressure relieving the valve cover/timing cover through the crankseal. Thats the sound you hear. >If you block the breather pipe for example, the exhaust gases blowing into the crank case will have nowhere to go and you'll start blowing seals all over the place. It's not a vacuum/pressure seal, it's an oil seal!<< Mate, yer doing me proud. See the post I made on the other list.. >Here's a guess. The dipstick tube goes quite far down, as already stated, the crank case will be under a slight pressure at all times, if you leave the dipstick out, you might find you get oil and not fumes pushed out the top. THAT's a guess.< The crankcase needs to be ventilated, we all know that. But where would the vacuum come from in a normal blowby enviornment? Most cars has warning about dipstick sealing, it's for the PCV system. >Question #8: Has anyone ever run their PRV with valve covers off?< Yes, I have. The function of the hose coming from the air cleaner to the oil beather is dilution air for burning the gases under the rocker covers. The negative pressure on that line comes from the vacuum line conected at the cold start tube, though a conductance limiting orifice. I never said a vacuum source wasn't connected to the valve covers, I said there was no vacuum under the cover. The vacuum line through the cold start pipe does not have the pumping speed to lower the pressure in the valve cover/timing cover volume, especially through the orfice and with all the outgassing occuring under the valve cover. In fact, if the large hose is piped to the atmospheric pressure at the air cleaner, how can the volume under the valve cover be evacuated thorugh the smaller cold start pipe hose and orifice? The answer is it can't. Sure, the limited conductance through the small hose and orifice would eventually reduce the pressure under the valve cover if that area were sealed. But due to the large hose "leak" from the air cleaner and the outgassing occuring under the valve cover, the pumping speed is far too limited to accomplish this. Under normal circustances there is not, and never should be, what you would call "vacuum" under the valve and timing covers. Ok, there *might* be a slight negative delta P in there but nothing you could measure with ease and certainly nothing that would effect manifold pressure or engine operation. Frankly, I think the outgassing alone over comes the pumping speed of the line, we'll forget about the huge hole the hose to the air cleaner represents. Again, does your engine falter when you remove the breathe hose or the entire oil beather? Come on folks, this is basic vacuum technology, not to mention basic engine stuff. The D isn't unique in this respect. 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=838581770> 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/> .
<<attachment: winmail.dat>>
Back to the Home of PROJECT VIXEN