<VV> Followup to engine cutting out

[Anil Mittal]

Hello All,

   Sorry it has been so long since my last followup, but it has taken
me this long to find the problem. You may remember I was having
intermitant fuel starvation problems in the primary carbs of my 66.
Armed with suggestions from the list I replaced the rubber sections
of fuel line, replaced the fuel pickup sock, installed an inline fuel
filter in the wheel well. With each fix the problem seemed to go away
but would then happen again. The funny thing was that just having the
car sit over night would allow it to start up again. Last night on a
hunch I decided to remove the fuel pump and put in a known working
replacement one that I had. I was feeling curious and wanted to see
how the fuel pump worked on the inside and how they would leak gas
into the oil. I put my old pump in a vice and removed the screws from
the top. I removed the rubber diaphram and piston and found the
inside had a large amount of metal chips and powder in it. I then
removed the middle section of the pump body and one of the check
vales just fell out of the body. I took a closer look and it seems
that the check valves are in a metal cage which is then pressed into
a metal bore and then staked into place. On the bore where the valve
fell out I notice that there was only 1 very light staking mark, not
two deep oned like the other check valve, I also noticed that the
bore was a bit chewed up. 

  I think 1 of two things could have been happening:

    The valve fell out of the bore the pump and the pump would stop
pumping, then somehow with cranking the valve would pop back in and
the pump would pump again.

    The bore would expand around the valve when the engine/pump got
hot which would not allow the check valve to work efficiently and the
pump would not pump. Then the pump would cool/contract back around
the valve and the pump would pump again.

   From what I have read on the list over the last 10 years the only
failure mode of a Corvair Fuel Pump is tearing of te diaphram and
leaking of fuel. I have never heard of this type of failure. Has
anyone seen this? BTW, the pump is from one of the Major Vair
Vendors. 

   Thanks for listening, hope I have solved my intermitant problem
which has been a pain to track down.

Anil