Morane 317 wrote:
:?: Can I ask for advice, please ? We have a Continental W670a fitted to a Morane 317 Parasol. Opening up a rocker cover we found traces of rust under the film of oil. We took off a cylinder and found rust under a thick film of oil on the crankshaft balance weights. We found patches of rust on the push rods - large areas were clean, and then a patch of rust that you can lever off with your nail. The oil we use is the one recommended by other Radial engine users, the aircraft is always hangared, but we are on an airfield about 1 mile from the Atlantic Ocean. Can I ask what oil other owners use ? Is this a known problem for the steels of 1940 ? If a "known problem" what to do ? Is there an additive we can use to remove the humidity which leads to rust ? We are stripping the engine down to clean all the parts, but would like to "solve" the problem, if possible. Thanking you in advance.
Camguard ASL is a relatively new oil additive that is FAA approved which is designed to help prevent internal corrosion on engines that are infrequently flown. Camguard has test data, and Aviation Consumer performed tests which appeared to confirm that if added to the mix, the product helps fight corrosion, compared to aviation oil alone. I use it in my engine.
Beyond that, people have experimented with dessicant dehydrators (I don't think that is a good solution - you saturate the dessicant very quickly). However, I think an industrious person could adapt a real dehydrator to the crankcase breather, the exhaust system, and the oil filler and keep things bone dry inside the crankcase.