<VV> Leaky Fuel Pump?

[Tony Underwood]

At 01:56 PM 6/8/2010, corvairs at pacifier.com wrote:
>Hi Mike, Not picking on you - this happens all the time.
>
>By your account you changed to an electric pump because you tried
>"everything". Someone who doesn't know better (a new owner) would
>therefore assume that mechanical fuel pumps are bad to rely on.


Well, he got it honest, because a lot of people on this list make 
that same claim...


>By your list lets dissect this correctly.
>
>NAPA - Napa has a huge reputation for STILL carrying the 1993 fuel pump
>recall run in their system. No mystery there. These pumps were made for
>about a 6 month period 17 years ago and WERE defective. Most were recalled
>except, apparently, from Napa.


Been there done that.   Got one of them behind me.  I use it as a 
demonstrator to 'Vair people to show them what not to buy.   Took it 
to a Nats Convention even, showed it around there (and to Cal Clark).


>THE SOURCE - I'm sorry, but it has to be said. Despite the Source's claim
>that their pumps were "the only ones that don't leak"


( my repair/rebuilds here don't leak )



>the fact is (and
>time has proven this) that he probably had more trouble with his fuel
>pumps - for a longer period of time, than all of us put together times 10.


...never tried one of his, but a bud did and put it on his Spyder, 
still going after some years.


>NOS AC Delco - 35-50 year old NOS anything with rubber is a gamble. I
>don't recommend that anyone rely on an NOS fuel pump.


The fuel pump on the engine in my '60 is the one it left Willow Run 
wearing.   It's a '66 model year engine, still untouched, original 
fuel pump still working fine but I DO carry another in the trunk with 
me.   As long as I do, the factory pump will never die.


>CLARKS - This is the only difficult one out of the batch. Clarks has
>normally sold Master (same as us) but I DO know for a fact that they sold
>Source pumps, and also other brands (including the supplier to Napa,
>Carter etc). I know for a fact that they have had troubles at various
>times with their pumps.


Those fiber-less diaphragm pumps appear to have been weeded out of 
their system... or sure as Hell should have been after all this 
time.  Last time I looked at a Clark's pump, it was one of the good 
ones with the right materials.


>None of this even starts to consider problems on your end.
>
>We have a superstitious predjudice in the Corvair community about
>mechanical fuel pumps. Like all superstitions they can be explained, but
>most folks don't want to listen.


Lon...    Remember about ten years ago, Back When, and one of those 
bad pumps slipped through your system and into the blue '69 Monza 
here?   Lasted a month...   The one you replaced under warranty 
without an argument, good service, although you were pretty disgusted 
that you'd sold one of the bad pumps?    It finally began misbehaving 
last weekend, bottom diaphragm started leaking, dripping fuel out the 
side vent hole, easy fix with a piece of viton diaphragm material I 
got from John Moody in that pump stuff I bought from him that time he 
was vending across the room from you in Carlisle, I think...  In this 
instance it looks like the gasoline being used these days was working 
on the bottom diaphragm which appeared discolored and slightly 
eroded, with a crack in it.   Ten years, I guess... the other 
diaphragms looked fine, however.  Again... easy fix.


The point is:   Of the 'Vairs here, not a single one is running on an 
electric pump.   If a fuel pump in one of them ever does demonstrate 
a problem, I repair it.   If the problem is freaky enough to be 
serious (like the one last fall with the warped body that leaked no 
matter what I did with diaphragms) I replace it with one of my other 
rebuilds.   On occasion, I have been known to buy a pump jus' 'cuz... 
like the one I bought recently when it showed up on an Advance Auto 
Parts inventory list in some warehouse, and could be at the store "on 
Monday afternoon" so I said "get it for me", and it showed up and I 
inspected the pump for the right diaphragm material, it passed 
muster, bought it, took it apart to check the innards, everything 
looked fine.   Didn't need it... still in the box on the counter by 
the kitchen.    Yes, there are 'Vair parts in the kitchen.

Corvair fuel pumps are simple.  Not a lot to go wrong... and it's 
usually diaphragms or on rare occasions, a check valve.   Or, very 
rare occasions, a warped body (which also is fixable).   I have 
absolutely no issues or angst or phobia about running a mechanical 
fuel pump on any 'Vair here.


...and yes, a new pump will need to have the screws snugged a time or 
two after installation to fully seat the diaphragms after which you 
can usually expect it to last for many years.   Occasionally I'll 
still send out the fuel pump comparison photo that shows what to look 
for if you buy a new pump, and how to avoid getting the wrong pump 
with the unreinforced diaphragms that WILL fail... and yes the same 
material was used on other types of fuel pumps for other marques and 
THEY failed as well.

The Corvair's mechanical fuel pump is NOT inherently prone to 
failure.   I've run too many of them for too long without issue to 
believe that.




tony..