Carried over from the
Valve cover baffle design thread. Dave brought up something I thought may be interesting.
simplyconnected (4/21/2009)
Yeah Charlie, I might have a dumb idea. After looking at my timing chain cover, it is obvious to me, that nasty, crank-bottom air was flowing up from the front of the oil pan,through those two holes (with the oil dam for the timing chain) and out the down-draft tube. Is there an air path that would circulate the air AROUND the inside of the engine?
- DaveThat's certainly not dumb. I don't think airflow through the engine has been discussed in detail. It may not be an area that needs improvement. Slightly more modern engines, such as the 305 in my Firebird, don't appear to have any kind of baffling to direct air flow in any particular way. I'm interested in hearing about it if there is anything important to know.
One thing, if your observations indicate that it's blowing up through the timing cover and into the valley, it must be drawing air from somewhere. The only source I can think of is through the distributor hole. I will guess that the hot crankcase gasses rise to the top of the engine where they can be drawn out and the cooler air will make its way to the crankcase. I guess that would be convection.
There have been at least 3 different arrangements for crankcase evacuation. It will be interesting, if not pointless, to know how they actually compare. My shop manual has a diagram showing how it should flow for the trucks original setup. I'll dig that out.
Lawrenceville, GA