I see that is question comes up every once in a while.
>From: andrew@server.uwindsor.ca (Templer Andrew)
>Subject: Long Term Storage - Up or Down?
I asked the question a month ago and received the following answer (I find it
worth posting).
>From a reader (The Mail SAAC). Here are a couple of articles on the subject
transcribed from the SHELBY AMERICAN a few years ago. The Shelby American is
a once per quarter publication of the Shelby American Automobile Club.
Copied without permission.
MINIMUM USE OR STORAGE
As the value of Shelbys and Cobras continue to rise, more and more cars will
continue to be restored and then used less and less - because as they are
used their condition deteriorates. This, in turn, effects their value. So
the question of storage is likely to come up more and more. We'll break it
down into two types of storage: long term and short term. Short term
storage is essentially a lengthened period of inactivity. The main question,
here, seems to be how long can you go without starting a car before you begin
to risk damaging it? And the answer is about 4 weeks. If you let your car
sit longer than that without taking special precautions (outlined in 'Long
Term Storage', below) you're courting disaster. The internals of your
engine, transmission and rear end are bare metal surfaces which are highly
susceptible to rust. In fact, they can cease operating effectively if they
begin to get even a slight amount of surface rust. They are bathed in oil
during normal operation and oil prevents rust. When the car sits, the oil
drains off of some of these surfaces. Moisture is the key ingredient
necessary for the rusting process and when the bare metal encounter moisture
the result is... rust. The less moisture in the air, the less the tendency
for rust to occur; dry weather in the southwest and colder temperatures in
the northern climes help to ward off rust. High humidity accelerates it.
Some so-called 'experts' advice people who don't drive their cars throughout
the year to start them up periodically to circulate the fluids and, thus,
keep the internal bare metal surfaces coated with oil. While this might seem
reasonable, it is the automotive equivalent of the 'old wives tale'. It is
exactly the WRONG thing to do. A car in short term storage needs to be
driven at least once a month. It requires more than just getting the water
temperature gauge off of the peg. The oil temperature should also be brought
up to normal operating conditions - and this isn't possible if the car just
sits in the garage - no matter how much you rev the engine. You need to take
the car out for a drive for about 20 miles or a half an hour. When you go
out to the garage to just warm the car up, what you're doing is raising the
temperature inside the block - but the engine doesn't run long enough for the
engine block to get entirely heated. As a result, when you shut the car off
the difference in temperatures (hot inside but cold outside) causes
condensation on the inside. Condensation is moisture - and moisture causes
rust. A car sitting too long without being run also invites fuel in the
carburetor and fuel pump to evaporate, leaving behind a gummy residue.
Gaskets dry out are then prone to cracking and disintegrating... more
things you don't want happening to your car's engine! So Dr. Hipo
recommends a half hour of exercise once a month, every month. On the way
back home you should stop off at the gas station and top the fuel tank off...
because condensation can also form on the inside of a partially empty gas
tank. The oil change interval isn't effected too much by inactivity.
Moisture can be collected in motor oil and if it is, it reduces the oil's
lubricating ability. Don't be pennywise and pound foolish thinking that you
don't have to change oil just because you've only driven the car 250 miles in
the past year. Under those condition, an oil change once a year is warranted
(although changing the filter probably isn't - you can stretch that to every
other year). Long term storage is another story entirely. Here, instead of
breaking that annual 250 miles into twelve 20-mile drives once a month,
you're using the car 250 miles all at once and then putting it away for the
next eleven months. Or longer. The way to prepare a car for this kind of
storage is to drive it long enough to heat the block (about 20 miles or so)
and then change the oil. With the car idling at about 3000 RPM, slowly pour
about a half a quart of oil down the carburetor. Be careful not to dump it
in all at once - pour it in a slow, steady stream. The exhaust will begin to
smoke and the engine may even stall. If it does, do not attempt to restart
it. What you've done is to coat the intake and exhaust ports, the valve
steams and guides, combustion chambers, piston surfaces and cylinder wall
with oil - the very surfaces which are most exposed to moisture - and rusting
- during storage. You should then seal the carburetor and oil breathers and
back off the valve adjustments until all the valves are closed. This buttons
the engine up so that moisture-laden air doesn't get inside the engine -
where it would come in contact with with bare metal surfaces. Hit all the
nipples with a grease gun (don't forget those hard to-get-to ones on the
universals!) and top-off the master cylinder, steering box, transmission,
rear end, radiator and fuel tank (and throw in a can of dry gas while you're
at it). Remove the battery and move it inside (do not store it on concrete;
if you put it on the floor sit it on a piece of wood). Raising the car up on
jackstands or blocks relieves the constant pressure on the coil/and or leaf
springs and helps keep the tires from dry-rotting and flat_spotting. It also
allows you to turn the rear wheels by hand every once and a while to keep the
transmission and rear end gears coated with oil. Finally, a coat of wax and
maybe a quick once-over for the interior with protectant or moistureizer and
you're ready to say 'so long' to your friend before you put the car cover on.
Now, you're probably asking yourself one final question: How short can
'Long Term Storage' be? In those parts of the country where winter driving
means ice, snow, sand and salt, most Shelby and Cobra are put away around
Thanksgiving - or at the first sign of freezing weather. They are brought
back out in the spring - after the rains have washed the residual sand and
salt from the roads. Four months isn't too short a time for the oil down the
carburetor treatment (but you may not want to mess with the valves). -Ed
Follow up response-
>From The Shelby American, #57, Copyright 1990 in response to an earlier
editorial response regarding car storage (The Mail SAAC). The Shelby
American is a once per year publication of the Shelby American Automobile
Club. Copied without permission.
LONG TERM STORAGE TIPS
I feel the advice given to your readers on the proper method to store autos
for the winter needs clarification.
1. Gasoline tank condensation and water contamination is not a big
problem as long as you fill the tank completely with gasoline. Just by
limiting the volume of vapor space above the gasoline, in the tank, you will
eliminate condensation related damage in the fuel tank.
2. Additives to eliminate water contamination in gasoline should be chosen
very carefully as most additive that advertise themselves as removing water
from fuel are alcohol-type products. It is true that alcohol will put
vagrant water molecules into a solution that will inhibit rust formation in
the gas tank as well as making the gas/water/alcohol mixture suitable for
burning. What people generally don't realize is alcohol is corrosive to
white metals and can do damage to fuel gauge sensors, line couplings and
carburetors.
3. The best method of preparing your fuel system for storage is to add upper
cylinder oil to your gas tank prior to filling the car and allowing it to mix
thoroughly by filling the tank. Pouring oil down the carburetor is not a
recommended practice in that most oils' additive package will not burn
properly and will foul both your carburetor and your spark plugs. If you
feel strongly about providing sufficient lubrication inside the carburetor
system, I recommend you increase the quantity of upper cylinder lubricant in
the gas tank, and spray the throat and exterior of the carburetor with a
light machine oil like WD-40 or a similar protectant after the car has been
placed on storage blocks.
4. The most important part of storing the car for a long period is to
protect the _cooling system_ from unnecessary corrosion by doing the
following: 1) drain and flush the cooling system (including the heater); 2)
replace coolant with 50/50 water/antifreeze solution (straight antifreeze is
also corrosive and should never be used straight); 3) add 4-8 oz. of water
soluble oil to the coolant and run the car until it reaches operating
temperature. The water soluble oil will turn milky in the coolant and will
inhibit the formation of rust and deposits on the surfaces of the water
jackets. Treatment with this type of oil will also inhibit dissimilar metal
corrosion that occurs naturally in most engines. If you have trouble
finding water soluble oil in convenient package sizes, products such as
"Bars-Leaks" are a good source of this type of oil. Regular oil will not
due.
5. An oil change to API classification SG motor oil is also recommended.
The formulation of SG will keep sludge deposits from forming in engines
subject to condensation such as infrequently run engines.
Shelby American Automobile Club
PO Box 788,
Sharon, CT 06069
(203) 364-0449
(203) 364-0769 FAX
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