Q: Regarding Narrow Deck and Wide Deck Lycoming engines, what would be the differences between a Narrow Deck O360 and IO360 heads, sump, and fuel pump? The cylinders appear the same.
BOB STOUGHTON, via email
A: The Narrow Deck vs Wide Deck question regarding Lycoming engines seems to surface from time to time. There is no doubt it can be a confusing subject, so I’ll try to keep the explanation short and sweet.
First and foremost, if you have a Narrow Deck engine, in this specific case, an O-360 with the engine serial number suffix ending in -36, it is not economically feasible to convert this engine to a Wide Deck engine configuration. The main reason is that the crankcase and cylinder assemblies are completely different. The cost of procuring new ones to make the conversion simply make it cost prohibitive.
Bob, in your case, I took it for granted that you were interested in comparing the O-360 parallel valve 180-hp engine with the IO-360 parallel valve engine. If that’s the case, then I question the reason for doing the conversion. Both of these engines are rated at 180 horsepower, so there is no advantage there whatsoever. The additional cost to convert requiring a completely different fuel assembly, again in my opinion, is just too costly.
I may have missed the reasoning behind your question, but I think the response above hopefully will answer your question. I don’t want to be a wet blanket on what your idea may have been, so if I’ve missed the mark, please let me know and I’ll give it another shot.