<VV> Re: pressurizing the fuel system

Tony tony.underwood at cox.net
Fri Nov 9 12:09:46 EST 2007

At 05:42 PM 11/8/2007, FrankCB at aol.com wrote:
>Based on my experience, if you put too much  pressure on the tank, you'll
>start to hear it CREAK!!  Keep the air  pressure below 10 psig 
>unless you want to
>expand the tank to a larger  size.<GGGG>
>     Frank "likes quiet tanks" Burkhard

For sake of mention:

I'd not put much more than 4-5 lbs in a Corvair tank in any 
event.   I did this once to help get rid of a dent in the bottom of 
an early 'Vair tank and it took almost nothing to cause the tank to 
distort and make dangerous sounding noises.   I'd bet that 10 psi 
could possibly come close to splitting a seam.

Now:  I *have* blown lacquer thinner through a gas line in a 'Vair, 
from the inlet pipe to the pump so as to clear a gummy/clogged screen 
in a tank filled up with who knows how old stinking gasoline... fuel 
pump would suck and suck but barely produce enough gasoline to keep 
the engine running at anything much faster than an idle.   Evidently 
the previous owner had kept adding fuel to the tank to insure his 
suspicions that the car wasn't actually out of gas because it 
wouldn't keep running.   It would "run out of gas" at anything much 
above 25 mph, have to crank and crank to get it to start again and 
then still had to wait for the bowls to fill enough to get the carbs 
to power the car.

He got tired of fooling with it, mostly because he wasn't 
mechanically savvy or whatever, left the car sitting for years before 
finally getting disgusted with it and selling it to somebody who also 
couldn't figure out what was wrong, who eventually sold it to 
somebody else who also etc and then he gave up and sold it to the 
nimrod who eventually sold it to us for almost nothing.

So, here it was with a clogged fuel line and a tank of sour gas and I 
wasn't interested in stinking up my person and patio while draining 
that stuff so as to gain access to the screen.

So...  I made sure the gas cap was OFF before funnelling a 
respectable quantity of lacquer thinner into the fuel line via a 
length of fuel hose clamped to the steel line in the engine bay which 
the previous owner had already sawed in half so as to run the car on 
a 1 gallon oil jug filled with gas stored beside the battery... made 
it convenient to clamp a piece of fuel hose onto the "northern" end 
of the fuel line (NEVER pump compressed air through a fuel pump) and 
then shot compressed air through the line while Linda listened at the 
filler spout up front for gurgling/bubbling noises.

The first forced-air lacquer thinner treatment helped but not 
enough.   Barely a bubble or two, and my lungs' huffing-blowing 
through the fuel line after the high pressure treatment moved almost 
nothing through the hose... a free flowing fuel line will allow me to 
huff and puff and blow into the hose and gurgle the contents of the 
fuel tank, but even the compressed air (cranked down to 25 lbs) 
wouldn't produce acceptable results.

Another refill of lacquer thinner into the fuel line and this time I 
cranked up the pressure to about 70 lb and let it rip.   It hissed 
and fizzled and the rubber hose swelled up and stiffened, then 
suddenly the hose deflated and air blew through the fuel line 
easily...   Yay, success, almost...  but too much too fast, blew the 
screen sock off the fuel pickup.

It also boiled up the sour gas in the tank and spurted a *big* belch 
of the stuff out the filler spout in a stream where it splashed onto 
the next door neighbor's yard...  evidently instantly killing any 
living thing that may have lived there.

...fortunately, Linda heard the pending gasoline puke-fest that was 
about to happen and ducked back away from the filler spout just as 
the sour gas spewed out.   What an interesting odor it made... and 
what a scene that would have resulted had she NOT jumped out of the 
way at the last moment.   Good instincts, I guess...  Not even tomato 
juice and lye soap scrubdown would have removed the aroma of rotten 
gasoline that she would have radiated for at least a week.

We never did tell the neighbor why a "human body sized" dead grass 
spot appeared in her lawn a few days later.   It did indeed resemble 
the shape and form of a body, as if a radio-active corpse had been 
dropped on it or something.

Trying to be nice, I eventually splashed down the dead brown spot 
with a solution of Dawn dishwashing detergent and watered it down 
thoroughly afterwards, then sprinkled grass seed onto the "laundered" 
spot and in a week or so it was turning green again.   Of course I 
did this when the neighbor wasn't around...

Afterwards, since I still wasn't in the mood to dig the sending unit 
out of the 'Vair, and seeing as how the previous owner had sawed the 
steel fuel line in half already, I simply installed one of those 
nifty "cleanable" glass case brass screen filters at the cut spot in 
the fuel line to keep trash out of the pump.   I did end up having to 
clean that filter several times before the tank finally cleared out 
and no longer gave any more trouble.

Oddly enough, as bad as it smelled, the rotten gasoline seemed to run 
the car reasonably well and it was a week before we put any fresh 
fuel in the car.

That was about 6 years ago, and the blue '67 coupe has been running 
along ever since, filter in the engine bay still working, and I 
imagine that the sock is still rolling around in the tank.


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