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Help ID Lycoming L166-47 narrow deck O-320 style engine

andyg

Active Member
Problem solved - Help ID Lycoming L166-47 narrow deck O-320 style engine

Can anyone tell me what this engine is.

Case is stamped L116-47. It has O320 induction and carb, and dual slick mags.

Thanks
Andy
 
Last edited:
Serial number

I am not sure if I am answering your question. The L116-47 is the serial number of the engine. Based on its low number (116) I would hazard a guess this is an older engine. Maybe '58 or '59. You can call Lycoming and give them the serial number and they can give you the history. With an engine this old they will have to go their historical files.

As for the rest of the engine, you said it is an O-320 with slick mags. What is the rest of the model identification if any, such as O-320-A1A. You can find it on the engine's data plate that is on the engine. With that information you can lookup your specific engine.

Here is one location that has decoded Lycoming's codes.

http://www.meyette.us/LycomingEngineNumbers.htm

You can also go to the FAA site and download the Type Certificate Data Sheet that contains operational information for your engine.

https://rgl.faa.gov/Regulatory_and_Guidance_Library/rgMakeModel.nsf/Frameset

I hope that answers your question.
 
Serial number

The dashXX denotes a series. For example -27 would be E series engines, some of that series have different front main bearings that do not support a constant speed prop although the case can be converted during overhaul. An A after the dash number denotes wide deck, dash 27 without the A would be narrow deck.
I have heard that some of the very early 0 320's are simply 0 320, no prefix or suffix. Those examples were most frequently installed on 1955 model year Pipers, some of which were likely manufactured in late 54.
 
Engine

With any engine builder that builds experimental engines all bets are off. As an example my 0 320 is built from a crankcase for an E series engine(-27A) which has the two piece front main bearing which makes the case eligible for other 0 320 engines and in some cases even an 0 360. The rest of my engine is mix and match. New Lycoming cylinders with aftermarket 10-1 pistons.
 
So what is dash 47?

L116-47....what is -47? That is the question.

And yes the dash nada is early. My data tag on the induction is dash nada. Sent to Piper March 15th, 1957.
 
Questions answered

Here?s the answer.

Anyone ever heard of an O-320-G4? So that?s what I have. Here is the partial answer. It?s a lycoming O-320-G4. A non-certified engine almost exactly like the certified version except for engine mounts. I has primer holes tapped and plugged. It has heavy (nomal certified as opposed to light ground unit) prop flange, and boss that is tapped for cs prop. May, 1961. And no ground unit front flange to cut off. According to Lycoming, this was an identical engine to the certified engine except not certified. It was the equivalent of the xo-320 today for the experimental market that was growing back then. He couldn?t explain the flat engine mounts instead of conical mounts.
 
I've been chatting with Andy trying to help him sort this out.

Apparently he has a very rare O-320-G4 mounted on the front of his one-of-a-kind homebuilt from the early 1960's.

Have any of you ever heard of this engine?
 
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