<VV> Mechanical and electric fuel pumps

[kenpepke at juno.com]

Frank DuVal wrote:
>Poll time:
>
>A. How many people have first hand knowledge of engine failure from 
>leaking fuel pumps?
>B. What percentage of Corvairs you know had this engine damage?
>
>Statistics-what a wonderful way to prove any point!
--------------------------------------------
My best friend, for almost 50 years, owns a junkyard.  In the old days 
lots of people would install electric fuel pumps to overcome vapor lock
problems and we saw hundreds of cars burned to the ground, sometimes
by pumps that overpowered the float needle seat dumping gas on the
hot engine and some from fuel line material failures caused either by 
changes in gasoline formulas or from old age.

We have seen lots of mechanical fuel pump failures of in line 6 and V8
engines.  Mostly they spray fuel out of a small hole and you can smell
the gas when you walk up to the car.  Lots of them pumped gas into the
oil pan ... And they are mounted low on the engine so they can siphon 
gas out of the tank when the engine isn't even running!  We found cars 
with as much gas in the pan as oil.  These engines showed no sign of 
excess wear or damage.

I had driven junkyard Corvairs for years and tens of thousands of miles.  I
have had a number of fuel pumps fail.  Most of the failures came when a 
one way valve popped out of its seat.  Simple solution was to take off the 
cover of the pump while it was still on the engine and stake the valve back in 
place with the end of the screwdriver right on the side of the road where it 
stopped.  It takes almost as much time to get the screwdriver out of the glove
box as it takes to make the repair.  I have had a few failures of diaphragm 
material but never had one either put gas into the oil pan or stop the car on
the road.  Usually they leak enough to smell the problem before they fail
completely.  I have had a couple of times when the eccentric on the cam failed
and ground the bottom of the push rod off.  The push rod will no longer move the
diaphragm far enough.  Of course you can change that eccentric on a Corvair but,
it becomes easier to install an electric pump.

Times have changed ... Materials have been improved.  Most cars on the road
today have electric pumps but we have not seen one burn a car down for years.
Changing the mechanical pump is easier than adapting and wiring an electric
pump and getting rid of the mechanical pump.  There is a certain amount of 
satisfaction in being able to drive an old car and keeping the original systems 
working adds the that satisfaction.  Of course, sometimes it feels pretty good to
upgrade things also.

Ken Pepke