[6pack] Gas in the oil?

[Dave Waldorf]

Unlike most American carburetors, the Stromberg CD and SU carbs have almost
all of the float chamber below the jet, so a leaking jet cannot be the
source of gas in the oil.  The idle problems could be related to a very rich
mixture resulting from a bad or poorly adjusted jet, but it would take a
VERY long time to get an extra quart or so of gas in the oil that way.



There is one way to get a lot of gas in your oil that is not related to ANY
defect in the car.  If you have a lot of heat built up around the fuel
pump/line/carb/etc., the gas will begin to boil.  This is called fuel
percolation.  Gasoline was reformulated in the late 1990s to standards that
are better for fuel injected cars and worse for ours.  It will begin to boil
at temperatures as low as 100 degrees F, and will boil dry at no more than
175 degrees F.  Those temperatures are easily exceeded in the engine
compartment under the best of conditions.



When fuel percolation happens, the boiling gas components push the still
liquid components along in the system, and eventually out the easiest
orifice (which is often the carb jet).  That gas is then free to run
down/along the manifold, past the valves, into the cylinders, past the
rings, and into the crankcase.  It will usually build up heavy carbon
deposits in the valves and cylinder walls along the way, fouling spark plugs
and making for a very rough idle.  Assuming the fuel pump is OK, I'd bet if
you pulled the spark plugs on this car they'd be black with a dry carbon
residue.



If you don't have a bad fuel pump diaphragm pumping gas directly into the
crankcase (with the poor idle caused by a resulting lean condition), then
this might be the problem.



Pull the plugs first.  Clean plugs mean the fuel pump's bad, black plugs
mean you need to put a heat shield on the carbs or take some other action to
protect the fuel from heat.



Good luck!



--Dave