[DeTomaso] Fuel tank vent install/fuel blockage resolution

[MikeLDrew at aol.com]

Hi guys,

Today was the day that I finally tackled the installation of the fuel tank 
vent, in the hopes that I could once and for all resolve the nagging fuel 
starvation issues I've been suffering off and on for the past year.   Chris Difani 
kindly offered up his extensively equipped (and extraordinarily dusty) barn, as 
well as his experience and creativity, to help with the task.

My drive up there was thankfully uneventful; the red fuel light was on as I 
left my house, and since it was a good 45 miles or so, the tank was fairly 
empty by the time I got there.

As Baldrick used to say on the BBC comedy "Blackadder", "I have a cunning 
plan!"   My scheme was to remove the fuel tank vent, and also remove the fuel 
filler gooseneck.   Once I removed whatever gick and debris was under the fuel 
tank vent flange (which I believed had been secured with RTV, which was being 
attacked by the gasoline), I was going to vacuum the tank clean, so to speak.

Chris has a mondo electric fuel pump, which is not yet installed in his car.  
 My plan was to stick a hose into the tank, run it through a clear filter, 
then to the electric pump, and send the output line back into the tank.   In 
this manner, I would just cycle the fuel while using a wand at the end of the 
fuel hose like a vacuum pickup to get any debris I could find, out of the tank.

We started out by removing the fuel filler gooseneck, which is necessary in 
order to remove the cover over the tank, which in turn is necessary in order to 
remove the vent.   That all went quite smoothly (shockingly smoothly in fact, 
thanks to a long allen-wrench socket with a ball end, gotta get me one of 
those!)

With that done, Chris cranked out a small die grinder and an aluminum 
grinding stone.   The aluminum stone grinding on the aluminum rivets would generate 
no sparks, but we took no chances and had fire extinguishers standing by.

With the heads ground off the rivets, the stock vent could be removed (by the 
way, I decided to do this job without removing the side window, which turned 
out to be a wise choice).   Once the vent was off, the rivet remnants had to 
be dealt with.   I crouched on the gearbox and held the bottom of each one 
(through the vent hole) with a pair of vice-grips while Chris used a spring-loaded 
punch to slowly drive the remnants of the rivet down through the respective 
hole.

With that out of the way, it was time to clean up any residual RTV goo (of 
which there was precious little) and then fire up the electric fuel pump vacuum. 
  It took a lot of futzing around to get the various fittings and hoses to 
let everything work, but eventually we had a very workable system, and I went to 
work.

I was able to look through the side window, straight down into the tank, and 
with the aid of a flashlight, see the bottom.   I had my wand/hose down there 
and was poking around, looking for debris.   There were a few flashes of 
brightness visible but much of the rest of the bottom was dark.   Then it dawned on 
me--my tank is aluminum (early '71 tank in my July '72 car, as my stock tank 
rusted to shreds and somebody gave me this one).   I looked closer, 
and...and....

...and, well, I just couldn't believe what I was seeing.   So I got rid of 
the wand/hose affair, Chris got a coathanger and bent it up, and we stuck it in 
there and pulled out this:

http://members.aol.com/mikeldrew/TankFuzz.jpg

That, my friends, is circa 1970s or early 1980s, and is a piece of a thin 
bedspread!   Note the ruler in the photo to show the size.

This sucker has been disintegrating and plugging up fuel lines for 30 years!  
 In fact a previous owner of this tank pulled it out of his car and replaced 
it, for reasons I didn't ever learn.   Now I know!

Can you imagine how many millions of miles I would have had to drive before 
this whole thing had made its way into innumerable fuel filters???

So, with that removed, now I could see the tank, and there was plenty of 
other debris visible. So we fired up the fuel pump again and I sucked around for 
about ten minutes.   There were some big pieces (not cloth--mostly globs of RTV 
I think) that were so large that they would just stick to the end of the 
metal pipe, so I would carefully extract it from the tank and then pick the debris 
off the end with my fingers.   But there was a bunch of other, smaller debris 
in there too, and in just a few minutes the new fuel filter looked like this:

http://members.aol.com/mikeldrew/ClearFilter.jpg

Lots of bits of aluminum (some from the countless rivets which had been used 
to secure things to this tank, and some from the tank itself, which had about 
nine holes drilled around the area where the flange attaches), as well as 
pieces of rag fuzz, RTV and who knows what else.

I was also able to directly see the fuel pickup in the tank, and noted that 
it had no sock on it, and evidently never did.   I guess that feature was added 
to the later tanks, and/or the fuel pickup incorporated into the fuel level 
sender.

We then cleaned off the top of the tank, and I laid down a thin bead of 
Hylomar, the whip-daddy sealant for these sorts of applications, then laid the new 
gasket in place, then another bead of Hylomar, then put the new vent/rollover 
valve in place and (with both of us working various ends of the rivet tool) 
secured it.

A vent hose went on, the fuel gooseneck and tin shield went back in place, 
and we were done.   Mission accomplished!

I now know that the coffee-cup-sized fuel filter I just added is superfluous, 
but I figure it can't hurt so I'll leave it in place.   

Fuel starvation has been the Achilles heel of this car for over a year, and I 
can now well and truly state that the problem has been resolved once and for 
all!   I am most grateful to Chris for helping out in this most noble 
endeavor.

I left his ranch and drove to the Sacramento airport and picked up Gray 
Gregory, who will be driving with me to Vegas.   Tomorrow we're going to the PCNC 
tech session at Roger Sharp's place; I have a small list of small jobs I want 
to accomplish on my car, plus a fellow is bringing a steering rack for me to 
rebuild.   Then Sunday is the Pacific Coast Dream Machines show, Monday we take 
care of various last-minute details, and Tuesday we're on the road to Las 
Vegas, baby! :>)

Mike


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