Not sure if there is a one size fits all answer to this but..
is there a system to how manufacturers number their engines. For example...lycoming IO540 C4 D5D.
my interpretation of this goes as such...
made by lycoming, it is a injected, opposed engine with about 540 cubic inches of cylinder volume.
im missing the rest, and can't seem to find it on the google of google. Any help would be appreciated.
A follow up question could bwhy can an aircraft with an io540 c4 d5d get a replacement engine without stc approval of it is still an io540, but maybe not the same attributes of the last two number sets?