Classic/Antique Car Repair: Fuel in Oil Pan, fuel pressure gage, pressure fuel

Question
Hello, thanks for the web-site!  I have a '67 Mustang and it's getting gas into the Oil pan.  I just had the carb 'rebuilt' and noticed the fuel is back in there.  I figured my next choice is replacing the fuel pump, I heard that's usually what the problem is when this occurs, is that true? any other way of locating the problem if it's not the fuel pump? thanks!  

Answer
Dave, the bottom of the fuel pump diaphragm drains right into the oil pan. This used to be a real problem in the days before synthetic materials when the fuel pump diaphragm was made of a rubberized fabric or earlier when it was leather. When the diaphragm develops and pin hole or crack it will inject fuel into the crankcase as the pump builds pressure. I have seen more than one engine with it's oil pan and or rocker covers blown off when the accumulated fuel in the oil pan went BOOM. To check the fuel pump disconnect the fuel line at the carburetor. Install a fuel pressure gage to the line. Usually a vacuum gage has marking and can be used as a low pressure fuel pressure gage. Start the and turn it right off. the gage should read around 4 to 7 pounds of pressure. The pressure should hold steady for 10 minutes or more. If it drops then the fuel pump is defective. Good Luck.
Brad