Question for Paul McBride, the General Aviation News engines expert: Thanks for your contribution to the aviation community. I have read Lycoming Service Instruction 1304J and wondered if I can expect to find a Form 337 for an engine on the CD the FAA sent me with aircraft records for a Cessna 172. The engine once had the following on the data tag: O-320-E2CC. I am told the engine was converted to an E2D per the logs.
In your experience is a Form 337 required? If so, am I required to transfer it to a new aircraft? I am picking up a C-172 project and doing my due diligence.
Sam
Paul’s Answer: I appreciate your kind comments regarding my contributions to the aviation community, but your question may be a real litmus test.
Sam, I’ve got to be honest with you here, what you’re asking about your engine conversion may be a situation of “you can’t get there from here.”
As you probably know, the O-320-E2CC indicates that the O-320-E2C was converted to an O-320-E2D according to the information you provided. After reading and re-reading the information, I can’t quite put my finger on what may have been done during the engine overhaul to convert the O-320-E2C to an E2D.
When I try to follow the lineage of the O-320 series of engines from the Lycoming Certificated Aircraft Engines publication, I can’t confirm that the conversion you claim to have is possible.
However, please don’t give up hope that the conversion was done appropriately by the engine overhaul facility and can be entirely explained according to the information in the completed FAA Form 337, which documents “Major Repair and Alteration.”
There is no doubt that a conversion like this should be covered, in detail, on a Form 337. Listing the specific engine components that were changed at the time of the conversion is absolutely required. This is the only way anyone would know “what is what” in the future for routine maintenance of a major repair to the engine.
My concern regarding this conversion is that the O320-E2C has a completely different front main bearing configuration on the crankcase as compared to the O-320-E2D, and I’m curious to know what steps were taken by the overhaul facility to get around that major difference between the two models.
Sam, I don’t mean to be a wet blanket on your project, but there are just too many questions here for me to come up with a reasonable answer for you.
Having raised some critical questions, this may be a good starting point to seek any and all information regarding the background of this engine. There is no doubt that doing your due diligence will result in a better, less complicated future for your C-172 project and, more importantly, save you money.
