merchauser

if the LH MAF boot hole is plugged, preventing any future oil ingestion, will residual oil that may have pooled in the bottom of
the lower intake eventually get whipped up and expelled thru the cylinders, or will the oil remain and need to be mopped up?

GregBBRD

Mop it up.

merchauser

no problem with manually cleaning it out, but curious about whether, eventually, that oil will get expelled? does that pool need to be a certain level before it gets drawn into the combustion chamber or does any amount of oil in the lower intake find its way into the cylinders?

dr bob

There's a critical intake air velocity and mass needed to move that pool from the intake. Normal US driving doesn't make enough of either, at least not for more than a few seconds at a time.

Reality is that the puddle probably won't hurt anything except your sleep patterns. At the same time, if you have the access to discover the puddle, you have the access to mop it up.

Plugging the vent line is a poor long-term method of "managing" the oil mist and combustion vapors carryover. There are several good separator methods that will reduce the oil mist carryover, while still safely capturing and re-burning the crankcase combustion vapors.

merchauser

thanks dr. bob. assuming this critical intake air velocity would take place at higher RPM's? how much oil or oil mist, would you guess it takes, to dilute octane or effect intake runner carbon crud? does the oil come in from the breathers and immediately get to the cylinders, or does it pool first, and then the intake turbulence create the ingestion?

when I did my intake refresh, I had a good amount of oil inside, and a fair amount of carbon in the runners.

for oil collected in the intake, is more oil coming from the oil filler, or from the rear RH cam cover elbow?

one thing I can say, is that greg brown's oil filler baffle, has made a huge difference! conducted an experiment with some clear tubing, and nothing is coming out from the oil filler.

Michael Benno

merchauser

dr bob

Oil mist is a concern, depending of course on how much actual oil is entering the chambers. And here's where oil choice starts to get more interesting -- most "real" synthetics have less of an effect on specific octane rating than conventional oils. Which are not "real" synthetics? Don't know. Amsoil has been a club racer's favorite for this very reason. Mobil-1 has a lot of racing followers, but that may be because of their sponsorship budget. Others have other opinions. I'd listen to Greg, since he makes careful educated recommendations so his engines can perform the best.

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Calculating the required "cleaning force ratio" required to move a puddle of sludge is a bit more work than just mopping up the puddle. That belly under the later manifolds is a good catch-basin for entrained liquids like oil mist when velocities and mass are lower. There might be a casual case for adding a drain port there, with a check-valve, to drop oil back into the crankcase when the engine is stopped. It's a weak case though, as that really does nothing for the problem, which is the oil mist while the engine is running. There are mountains of engineering dedicated to the subject, including Greg's systems that scavenge cam cover vapors, separate the oil, pump the oil back, and recirculate the scrubbed combustion blow-by vapors back to the intake. Search for some info on Ford's efforts on the coyote engine for a clinic on the subject.

merchauser

^^^^great information. thank you