Q: I just purchased a 1978 Citabria 7ECA with a Lycoming O-235-C1. Just had my first oil change done — it has no oil filter! Just one, maybe two, screens. Are these screens just as effective if I change my oil every 25 hours? Should I add an oil filter? Is that even possible? I run Phillips X/C and CamGuard. Your thoughts?
Jimmy Schramm, Tampa, Fla.
A: Jimmy, the question you’ve asked is a common one and not only applies to your O-235-C1, but to most all Lycoming engines. The answer to the question can you add an oil filter is yes, you can, providing you have the space between the engine and the firewall.
However, I would not add an oil filter to the engine if the aircraft were mine, so the answer to this question is no.
The reason I wouldn’t do it is quite simple, using your situation as an example.
First, I wouldn’t spend the money, and second, with you changing your oil every 25 hours, it’s easy to keep tabs on the engine health as far as detecting any telltale signs of wear taking place inside your engine.
The important thing here is to be certain to remove, inspect, and clean the oil pressure screen every time you change your oil. You should also remove, inspect, and clean the oil sump suction screen located in the engine oil sump. This oil suction screen is not as fine as the oil pressure screen, but will collect larger pieces of contaminates, such as pieces of carbon, etc.
I’d like to recommend that you continue to change your oil every 25 operating hours, but also do it every four months as well.
The reasoning behind this is that you are removing the contaminates from the oil, which are by-products of combustion and moisture. It’s these things that cause internal engine problems over time if the oil is not changed on a regular basis.
I’d recommend you ask your maintenance facility to let you look at or give you a copy of Lycoming Service Bulletin 480E, which addresses the subject of oil and filter changes and screen cleaning.
I think because you live in a rather warm climate, you probably don’t get as much moisture in your oil as an aircraft based in a cold climate or where the engine sees radical changes in outside air temperatures in relationship to the internal engine temperatures, but I’d still feel following the 25-hour and four-month recommendation would serve your engine best.
While many people will argue that the oil is still good — and I wouldn’t argue that point — it’s the contaminates in the oil that I want removed from the engine because it’s those that cause the internal corrosion that we don’t want if the oil is allowed to remain in the engine for long periods of time.
I’ve tried to get the message across to aircraft owners, pilots, and anyone who would listen that the two least expensive things you can put in your engine are fuel and oil. Translating that into simple language means change the oil frequently according to Lycoming Service Bulletin 480E or its latest revision and don’t lean the fuel mixture aggressively.