TULZ - Part Six
Veeduber
FIRE!
Gotta fire extinguisher? No? Howzabout a bag of marshmallows? Cuz
if you own a Volkswagen you really should carry one or the other. Your
choice.
On average, it takes a 15 lb dry-type fire extinguisher to snuff an engine
fire on a Volkswagen. That's assuming you know what you're doing and
jump right on it. Assuming you've got one on-board. And can get to it.
Bus owners should carry two, one reachable from the driver's seat, the
other from the cargo-bay door. Jump on it quick and the damage can be
limited to the wiring, fan belt and hoses. But if you dawdle the fire will
ignite the magnesium crankcase and tranny. Ever tried to put out a
magnesium fire?
Come to think of it, have you EVER used a fire extinguisher? Old sailors
like me know how; firefighting and damage control is part of Navy boot
camp. (Why? Cuz you can't walk home.) If you've never donated
eyebrows to the Maltese Cross it wouldn't hurt to check with your local
Fire Department. Most of them will be happy to show you how tackle a
gasoline fire. There's a bit more to it than Point & Shoot.
(Funny-Sad Stories: Woman's westy catches fire. No problem, she has
a big extinguisher. Lugs it around to the smoking vent… and finds she
can't pull the pin, unaware that particular extinguisher requires the
handle to be partially depressed to allow the pin to pull free.
Marshmallow event. Similar but different case: Plumber in his service
truck sees a VW bug smoking on the side of the road, pulls up to help.
Discovers the safety pin on his extinguisher has had the end peened
over. Has to find a pair of pliers to free the pin, by which time it was too
late to do much good.)
------------------------------
Volkswagens like to catch fire, mostly because of you; because of the
things you do and because of things you don't.
A fire stands on three legs, fuel, air and a source of ignition. Chop off
any one of those legs and you don't have a fire. With a car, you can't do
much about the air or the source of ignition so you focus on the fuel, the
gasoline.
Pound for pound, gasoline has more potential energy than dynamite.
Toss a kid a two-pound stick of 20% Hercules and he's liable to crap his
pants. But give him an even more dangerous quart of gasoline and
watch the foolishness begin.
Here's a good example. See that cute little fuel filter? The one between
the fuel pump and the carb? You probably paid about two bucks for it
even though it only cost a nickel, wholesale. When you installed it you
thought you were doing your ride a favor but the truth is, those two bucks
can cause your Volkswagen to catch fire. Herez how: The added mass
of that little filter, combined with the normal vibrations produced by the
engine and the surface of the road, is enough to loosen the brass ferules
in your carb and fuel pump as the hose wiggles up & down. And once
they come loose, they pop out. The engine keeps right on running of
course – there's plenty of fuel left in the carb. And so long as the engine
is running, so is the fuel pump. The gasoline gets sprayed all over the
engine compartment and is ignited by the sparks from the generator or
the distributor (there's plenty of sparking going on inside your distributor
and it's open to the atmosphere).
That little fuel filter can be the dumbest two bucks you'll ever spend.
Volkswagen provided your fuel system with a strainer in the fuel tank and
a fine-mesh filter – finer than any orifice in your carb – in your fuel pump.
When they went to the non-rebuildable pump they put the filter under the
fuel tank.
The filter in your pump is supposed to be cleaned every three thousand
miles. Nobody does, of course. Too much work or something. Instead,
they buy one of those kewl two-dollar filters that everybody sez is such a
smart idea. The only smarts in this equation is the 2000% mark-up on
that crappy little filter :-)
So why'd folks start putting filters between the pump & carb? Because
either the gas tank or the fuel pipe was starting to rust. The VW is a
cheaply built car, the fuel tank is made of plain carbon steel. It loves to
rust. When it does, you don't add filters, you deal with the rust. You
pull the fuel tank, etch it with acid then slosh it with PVA sealant. Bingo!
No more rust. Or you replace the fuel pipe. Or both. (See the real
Volkswagen Workshop Manual for the repair procedures.) [Roland
Wilhelmy replaced the fuel pipe in the tunnel of his '57 with a single piece
of stainless steel tubing. He put threaded fittings on either end. Neatest
bit of plumbing I've ever seen on a bug.]
The punch line to the joke is that lotsa kiddies will spend thousands of
dollars getting rid of the rust on the OUTSIDE of their Volkswagen but
ignore the cancer in their fuel tank, even though they know it's there.
That's why the bought the filter, right? (And if you haven't figured it out
by now 'kiddie' has nothing to do with age. It has to do with acting in a
childish or immature manner.)
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So you check the brass ferules on your fuel pump & carb and, big
surprise, they're loose. Now what?
The best fix is to replace them with threaded fittings. There is some
aircraft stuff that is small enough to fit the casting yet provides adequate
flow.
Or you can knurl the ferules and reinstall them with a dot of sleeve
retainer. And then safety the hose. Herez how.
To knurl the brass tube you use a mill-cut file as a knurling tool. ( A mill-
cut file has just one row of teeth across the face of the file.) You put the
brass ferule on a piece of smooth wood then press the file down on top
of the brass tube then ROLL the tube by pushing on the file. The teeth of
the file will EMBOSS grooves in the brass and in doing so, increase the
OD of the ferule. Making it larger in diameter makes it fit tighter in the
casting. (No grooves? Press harder. The hardened teeth of the file
WILL emboss the softer brass. Just be sure to use a block of hard wood,
leather or plastic for the 'anvil' on which you do the rolling. If you roll it
on metal, the metal will simply flatten the grooves out again, as fast as
you make them.)
So go clean the casting (ie, the carb or the fuel pump). Chuck something
into your Makita, put a wisp of fine steel wool on the tip and polish the
bore in the casting. When it's shiny, swab it out with MEK and a Q-tip.
Now the sleeve retainer will bond to the pot-metal casting.
Got your sleeve retainer? Sleeve retainer is high-strength loctite, the
green stuff. Use MEK to clean the ferule you've just knurled, put a dot of
sleeve retainer on the knurled part and drive that sucker into the bore
with a well aimed tap of a hammer. Then let it cure for 25 hours. 24 if
you're in a rush.
Install the fuel hose with clamps on both ends. To safety the hose, use
light-gauge safety wire, the same stuff you use to safety the set-screw on
the shifter-rod (I think it's .028; mebbe .016. Either size is commonly
available. See the Harbor Freight catalog.) Make a double wrap around
the hose BEHIND the clamp then secure the wire to the carb or fuel
pump. Now even if something comes loose, the worst it can do is leak; it
can't blow off and spray gasoline all over the engine.
The other common cause of engine fires is due to your failure to replace
the grommet isolating the fuel pipe where it passes through the forward
breast tin.
Back in the good old days, whenever that was, every time you took your
Volkswagen in for service they'd check the grommet. (You check it with
your thumbnail.) If it was hard, they'd replace it. And it got hard pretty
quick since it's only inches away from the #3 exhaust stack, which runs
red hot at highway speed. The rubber grommet soaks up the radiant
heat from the cherry-red steel and cooks itself harder than a bride's
biscuits in no time at all.
Once the grommet gets hard it cracks into pieces and falls out, leaving
your fuel pipe to rub against the .025 edge of the sheet metal of the
forward breast tin. Now, you wouldn't think a piece of sheet metal would
make a very good saw but remember, it only has to cut far enough to let
the fuel spray out. And that don't take long at all. So now you got raw
gasoline dribbling out the fuel pipe just inches from the #3 exhaust stack.
See why you need to carry those marshmallows? No sense letting a
good bonfire go to waste :-)
So what to do? You can just keep putting grommets in the hole but
that's sorta lame. It was okay back then; cheap car, inexpensive service,
only takes a few minutes to replace the grommet. And so long as you
had the vehicle serviced by the dealer there was never a problem. But
times change. Nowadays, the whiz kid at the local quickie lube
emporium wouldn't recognize a grommet if it ran up and pee'd on his leg.
And even if he did, he'd want a zillion dollars to replace it, being a highly
trained technician and all.
So you install a bulkhead fitting, which actually isn't. Bulkhead fittings
are threaded on both sides. What you'll make up looks kinda like a
bulkhead fitting but it's actually a 'pass-through'. Easy to make. Cost
you mebbe two bucks. No more grommet, no more fuel-pipe failure and
no more fuel-pipe-related fires. You can leave the marshmallows at
home. (But keep the extinguisher in the car. Shit happens.)
To make your bulkhead fitting you begin with a piece of Volkswagen fuel
pipe, three inches long. Quarter-inch tubing (that is, non-metric SAE
stuff) is a little bit too large for the stock VW fuel hose but a SAE brake
line stock, which is available from most FLAPS, is close enough to work.
The three-inch long piece of fuel pipe must chamfered on the ID at both
ends and then the ends must be carefully smoothed with #600 paper.
Finally, you need the flare the ends just a tad to create a SMALL lip to
secure the hose. Be careful here. Small means exactly that. You can
feel the flared lip but it isn't obvious to the eye. The important thing is
that the hose will feel it too.
The other parts for the bulkhead fitting are down at your local hardware
store, hanging on the rack with the other ELECTRICAL repair parts. Ask
for 'lamp repair parts.' A common brand-name 'Angelo' (ie, Angelo
Brothers Co., from Philadelphia). You want a threaded barrel one-inch
long. It will probably come in a blister-pack with an assortment of barrels
of other lengths. The 1/8-IP thread is standard for all lamp stuff so don't
worry about it; lamp nuts fit on lamp barrels.
Once you have the barrel you need two nuts to fit it. They'll be hanging
on the same rack. If they have internal-tooth lockwashers for the nuts,
get some.
The other part of the kit is a pair of fender washers having an ID large
enough to accept the threaded barrel.
Lamp hardware comes in both brass and steel. Brass will work but the
steel stuff is stronger. If you live in the rust belt, brass might be a better
choice. I assume you'll paint the steel stuff.
To assemble the pass-through you want to bed the piece of fuel pipe in
the threaded barrel. To do this, insert the fuel pipe into the barrel for
about an inch then slather RTV on the exposed fuel pipe for a distance of
about an inch. Now insert the slathered fuel pipe into the barrel using a
twisting motion. You want to end up with an inch of fuel pipe projecting
from each end of the threaded barrel and the fuel pipe firmly bedded in
RTV inside of the barrel. Once you've achieved that, put the thing aside
to cure.
To install the pass through you spin a washer (and lockwasher, if you
have it) onto the barrel, about half-way down. Then slide a fender
washer onto the threaded barrel so it comes up against the nut (or
lockwasher).
The object is to insert the threaded barrel through the hole in the forward
breast tin and form a sandwich of fender washer – breast-tin – fender
washer, secured by nuts on either side. That's the goal. And it works.
But the first few of these I made, the nuts came loose. I used
lockwashers and even two nuts on each side but given the heat from the
exhaust stack and the vibration, the things eventually loosened up.
So I glued it together. I used some high-temp (red) RTV and liberally
buttered the washers & nuts before tightening the thing down. That was
in 1981. It's still tight. So use the RTV trick to keep it from coming loose.
Stock VW fuel hose will push over the SLIGHTLY flared ends of the fuel
pipe. You should then install hose clamps but do so LIGHTLY. You
don't have to tighten a hose-clamp very much. The combination of the
clamp and the small flare effectively locks the hose to the pipe.
There are some details here you should be aware of. The old fuel pipe
will need to be shortened. I use the stock bracket on the end of the
blower housing to secure the stock fuel pipe. On some vehicles the
bulkhead fitting can be difficult to install with the engine in the vehicle. I
think it's a mod worth dropping the engine for but then, I drop the engine
just to wash the engine compartment.
One thing you should do IMMEDIATELY is go out to your car and check
that damn grommet. IF it is hard or missing, replace it NOW. A quick but
TEMPORARY fix is to slit a section of suitably sized hose, clip it around
the fuel pipe, slide it into the hole in the breast tin and slather it with
high-
temp RTV. In theory, that should work at least as well as the grommet
and maybe as well as the bulkhead fitting. But in practice, the thing
tends to come adrift, possibly because it gets gasoline on the RTV or
mebbe from the heat or… something. The metal barrel works best. But
you're the Mechanic-in-Charge. Your ride; your decision.
The grommet problem isn't new. It was first identified as a cause of
Volkswagen engine fires about 1958. In the 1960's I used aviation-grade
bulkhead fittings on my Volkswagens, replacing all of the stock fuel
plumbing with higher quality aviation stuff. That's when I was working for
Uncle Sam and he didn't mind if his nephews diddled the system a little,
so long as the planes didn't fall out of the sky. Not too long after leaving
the Navy I needed a bulkhead fitting, saw how much the silly things cost
and came up the lamp-parts arrangement as a substitute. It works.
-Bob Hoover
-20 April 2K
John Willis
direction...
~~~~~~~~~~~~~~~~~~~~~~~~
John Willis
jdwi...@airmail.net
John Willis
nut fitting instead of the hose and clamp? Do you really need the
flexability of the rubber gas line or could you run a solid line this
way with flare fittings on either side of the bulkhead fitting?
Thanks,
~~~~~~~~~~~~~~~~~~~~~~~~
John Willis
jdwi...@airmail.net
Veeduber
John asks:
>About the bulkhead fitting, is there any way to saftey wire a flare
>nut fitting instead of the hose and
Yes. There are several ways of doing so. One is an oblong washer-like device
with tabs that are bent up to align with the flats of the nut, preventing it
from turning. The end of the oblong is provided with a hole for the safety
wire.
You can also find aircraft tube & hose fittings that are already drilled for
safety wire.
<Do you really need the
>flexability of the rubber gas line or could you run a solid line this
>way with flare fittings on either side of the bulkhead fitting?
>
You should consider a real bulkhead fitting. Get the catalog from an aircraft
supplier or from Earl's equipment. Install a regular bulkhead fitting and run
pipe from it to the fuel pump. But you will need hose between the chassis and
the bulkhead fitting and between the fuel pump and the carb. In the former
case, you must use hose because the engine moves at a different frequency than
the chassis. In the latter, the carb is not sufficiently rigid to allow use of
a fuel pipe. It needs a 'third leg' -- a strut of some sort -- to offset the
pull of the throttle-wire. This is easy enough to do but a flexible fuel line
is more convenient.
-Bob Hoover