Engine oil advice

[Morane 317]

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.

[Kyleb]

:?: 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.

[ajanik]

We operate a number of radial engines. We have also noticed the type of corrossion you mentioned in our low utilized engines. We have begun to use Aeroshell "Plus" engine oil which has a corrossion inhibitor added to it as well as inhibiting the engines that we do not fly during the winter months with aeroshell 2F preservative fluid. When we do operate our engines we try and carry out flights long enough to heat all the engine oil to above 180 degrees to boil of any condensation, usually a min 1 hour flight when we can, we also avoid unnecessary short ground runs. These are some of the things we are trying to minimize corrossion in our engines.

[shrike]

Our shop only does horizontally opposed engines, but we've run into similar problems. (Mostly as customers seeking warranty concessions for improperly stored engines)

Ajanik is spot on. If the engine is going to be inactive for more 30 days you should plan on doing a full long term preservation on it. Lycoming SL 1080B http://www.lycoming.textron.com/support/publications/service-letters/pdfs/SL180B.pdf is a good place to start as it's fairly generic. Continental's advice is similar.
Any engine we do that won't be immediately installed gets this treatment and we've had pretty good luck with it.


Preservative oil, dehydrator plugs and a tight fitting set of plugs for inlets and exhaust will go a long way towards extending the life of the engine. Make preserving and un-preserving (?) the engine part of the seasonal inspection and maintenance schedule.