Why are some Lycoming engines built without oil filters?

My friend and I were discussing why many Lycoming engines were built without oil filters, just oil screens. He guessed it was because in the beginning they just didn’t have oil filter technology, and once certified, the engine design is hard to change, so they just stayed that way for a long time.

My conjecture is that the very smart engineers at Lycoming designed an aircraft engine, not a car engine. They wanted it to be light in weight, reliable and make the TBO of 2,000 hours. I say to accomplish that an oil filter isn’t needed. An oil filter is dead weight and one more place for something to go wrong. A good air filter and changing the oil more often is better.

Please tell us the answer.

Larry Hall

Morgan, Utah

It sounds like an interesting discussion you had about oil filters or the lack thereof on Lycoming engines. At one time during my years at Lycoming I was in domestic OEM sales, which means I was responsible for selling engines to several of the major airframe manufacturers. I’ve often used the example when describing the process that takes place when Lycoming is approached by an airframe manufacturer to provide an engine for a new model they had in the pipeline that it’s just like you going to your local automobile dealer and buying a new car. You have the choice of buying a less expensive automobile that may not have all the bells and whistles. However, if you want a six-disc CD changer or a rear video player for the kids to watch, then you pay more money for those optional features.

When an official from an airframe manufacturer comes to Lycoming he usually knows what horsepower and some of the more basic criteria needed. Then he is offered lots of optional items like oil filters, provisions for a vacuum pump or prop governor, among others. The deciding factor is what the manufacturer wants to achieve and, last but not least, how much money the company wants to spend. Just like your rear video in that new car, if you want the frills, you’ve gotta pay.

Not providing an oil filter is not a bad thing and it does add cost to the engine to have one as part of the package. There is no argument that the filter provides somewhat better filtering and allows you to go more operating hours between oil and filter changes. The oil screen configuration still performs the service of screening all of the engine oil as it passes through and collects small carbon particles and other foreign material which could prove detrimental to engine life if not trapped in the screen. It’s understood that the oil filter performs this task better and traps additional elements that would just pass through the screen.

Lycoming has what I consider to be one of the best Service Bulletins out there regarding oil and filter change and screen cleaning. SB 480E or its latest revision should be religiously followed by all to ensure your engine is properly maintained. Failure to comply with this SB may, in fact, reduce your engine’s life and increase your maintenance costs. Remember that oil and filters are two of the least expensive things you can put in your engine.

Regardless of which configuration your engine has, the important thing is to change the oil and filter and clean the screen as set forth in Service Bulletin 480. I’d also suggest you confirm that the suction screen on your engine is being inspected and cleaned too, as mentioned in the SB.

Paul McBride, recognized worldwide as an expert on engines, retired after almost 40 years with Lycoming. Send your questions to: AskPaul@GeneralAviationNews.com.

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