If you are flying an aircraft with the A or C Series Continental
engine that uses the Kidney shaped oil sump, you probably know that they
are expensive to replace. They get dented when the carburetor is forced
back in an accident. Fortunately, the opening where it attaches to the
engine is large and a good body man can work out the dents. Here is
another option for dent removal without a bunch of hammer dings that
will happen if you are not a good body man.
Mount the tank to a steel plate to seal off the large opening. Get an
expanding plug to seal the filler tube and apply pressure to the tank .
Then use a torch with a soft flame to heat the dent, and it will round
right out. But be careful; it is easy to have too much pressure and have
a blow out.
My respondent doesn't say how much pressure nor how to pressurize. I
would tap the steel plate for a "schrader type" valve or use the drain
plug with the appropriate pipe reducer. Maybe as low as 5 to 10 lb. air
pressure. You can always increase the pressure if heating to dull red
doesn't do the trick. "Be Patient."
One of the Mites I am restoring had such a damaged oil tank. After
reading the above article I did the following. First I washed the tank
in my parts washer, found three small leaks and brazed them. Cut a steel
lid out of scrap plate. Drilled the plate to match the mounting holes
around the big opening. Put a central hole for the schrader valve (NAPA)
purchased a low pressure tire gage 0-20 lb. PSI (NAPA) cut a gasket out
of oil soaked poster board to seal the big opening. While a (NAPA)
purchased an expanding plug to fit the filler neck.
Now this tank was badly damaged I doubt if the tank would have held a
quart of oil. One side was concave and almost touching the other wall
besides the three small leaks. The tank was worthless, so was quite a
challenge. Put in about 7-8 lbs. air and began heating the worse dents
on the tank. By constantly moving the tip I was able to get the metal to
move out. I kept checking the air pressure and occasionally adding
additional air and at one time had a maximum pressure of about 15 lbs.
Believe it or not but it worked. After sand blasting and painting you
would not believe it was the same tank.. I think that a rose bud tip
would have been better but I used what I had available.
Total cost of repair not counting the gas used or time was less than
$10.00. I now need an oil cap for a long neck Kidney sump with a dip
stick.
