Engine accessory case: port ID

[nichzimmerman]

Given the number of variations on accessory cases and the fact that many accessories have ports on them, we need a thread dedicated to identifying those which are not clearly indicated in the various Lycoming manuals. (There is a single thread in existence but is titled Oil Cooler Lines). I couldn't find this anywhere on the internet.

Would anyone care to identify the function of those ports marked with a question mark in these pics? While you're at it, please verify my labeling is correct. This is an O-540-A1D5.

 

[svyolo]

I have a better one somewhere.

 

[Steve W]

#3 is oil temp. #2 is usually capped on the 4 cylinder unless this is an oil cooler supply port instead of the one below the filter assembly.

 

[Bcone1381]

This is a link to the PDF of the Lycoming's O-360 operators manual.
https://www.lycoming.com/sites/default/files/O-HO-IO-HIO-AIO & TIO-360 Oper Manual 60297-12.pdf

Go to page 7-6 to find two different oil screens for Oil FROM cooler, Oil TO cooler, Oil Temp. The following page 7-7, thru 7-16 looks like the image below. That will give you a lot of info. But I Don't know off the top of my head where to find your oil filter adapter information.

 

[svyolo]

That is the one I was looking for. It is somewhere on my laptop.

 

[nichzimmerman]

Thanks folks. Comparing Steve' hypothesis on #2 to the centeral diagram on Fig 7-3 (page 7-6 in Brooks' link), there is a strong case to suggest #2 is an oil line. Furthermore, I snapped a pic of where I expected the "oil to cooler" line to go, and found it was plugged, probably since the original paint job. And, the #2 port has the same flared fitting as the "oil from cooler" port. Now I just need to figure out what to do with #1.

 

[Steve W]

Plug it. Quick call to Bob could confirm what to do.

 

[svyolo]

On my Bob 540 your #1 has an 1/8 NPT plug (transducer port?), #2 is a safety wired plug (probably a straight thread) but is probably an oil line. I have no #3. I don't have a filter and adapter on the back of my engine, I have what I believe is just a oil screen and/or vernatherm housing. I don't know what it is called. Your #3 is on what looks to be an adapter to fit the oil filter. If the threads are straight threads it is probably for oil temp as my oil temp port is on my oil screen/vernatherm housing and uses straight threads.

 

[nichzimmerman]

Hard to believe I started installing the engine over a year ago. Still, confusion abounds. What is the port on the carb just above the fuel inlet fitting? It has a plastic cap in the picture.

 

[Paul Johnston]

May have been a fuel source for engine primer

 

[Chris Werner]

My o-540 had a hose going to a fuel pressure guage coming from that fitting.