mixer wrote:I noticed that there was an unresolved question as to how much of a pressure drop before blow-by begins
Hmm, hadn't noticed that.
But I do notice a lot of "blow-by" gasses from older Benz's especially when the owner avoids setting the manual valve lashes every 12.5km.
For all the members here who drive them, an easy way to evaluate the blow-by on any Mercedes-Benz 61x series engine is this:
1) warm the engine to normal operating temperatures (80C/175F)
2) park the car with the engine running
3) open and secure the hood
4) unscrew the oil filler cap on the valve cover and set it on the hole.
Likely it will dance around while some smoke and oil sputters out.
If the "blow-by" gasses from the pistons and/or valves are pressurized enough and blow the oil cap off the valve cover, you might have a problem. . .
5) put the cap back on. Likely you wouldn't be surprised by how many people forget this critical second to last step before they,
6) go home.
Best,
-Patrick Kennedy
p.s. Just be thankful that I am not adding this as my sig line ;^)
In 1978 my Mercedes-Benz manual was printed with the recommended of adding up to a maximum 30% gasoline in emergency and emergency Winter situations only. Both diesel fuels and gasoline fuels blends were very different in 1978 than they are today in 2008 or will be in the very foreseeable future. Mercedes-Benz has since updated and maintained their owners manuals and reference literature to reflect the current face of automotive fluids and other appropriate consumeables. In their US$50 billion annual R&D budgeting wisdom, they have "converted" their recommendations for emergency fuel options to reflect the "converted" ASTM options for passenger and ULSD fueling. Please do not consider either the old or updated recommendations for emergency fueling situations as advice the manufacturer would recommend for commuting, regular or daily fueling situations, whether your ride is stock, modified or "converted" Don't take my word for it. Visit your local dealer or call today and register your vehicle identification number with 1800 FOR MERC. They will email you a .pdf or send you the literature so you
don't ever need to call and ask for their free roadside assistance program (M-B USA).