This is by no means complete but it should give some insight to what you are looking at if someone is selling an oil sump and you are not sure what it is for or if you can use it. I hope some of you find this useful.
The first photo is an early sump from an O320 A2B. This one does not have the cast in oil pickup and it uses 1 1/2" inlet tubes that remain small all the way to the cylinder head. The pickup tube bolts to the inside of the accessory case and there is a pipe plug that must be in the bottom of the accessory case to use this sump. Later sumps can be used to replace this one but it requires removal of the plug and blocking off the pickup tube location in the accessory case.
The second photo is of the early tube. I believe the 150hp engines may benefit from the smaller intake tube to maintain mixture velocity with low compression.
The third photo shows the tapered spigots that are used on later 320s. The larger tubes (1 3/4")are the same size as used on the 360/540 engines. These sumps also have smaller runners than the 360 sumps.
Photo 4 is an IO360 sump with the larger, straight spigots. This is actually in use on my 320, so yes the 360 sumps will fit the 320 case. Make sure to get the tubes that are for the case as there are many different tubes and it could be a major ordeal to get the correct ones. Sense the 320 cylinders are shorter than the 360s you may need to shorten the tubes a small amount.
There are many different sump configurations and now days there are aftermarket sumps that may differ from the original Lycoming units, but that's another subject.
Anyone with additional information or variables is welcome to add.
The first photo is an early sump from an O320 A2B. This one does not have the cast in oil pickup and it uses 1 1/2" inlet tubes that remain small all the way to the cylinder head. The pickup tube bolts to the inside of the accessory case and there is a pipe plug that must be in the bottom of the accessory case to use this sump. Later sumps can be used to replace this one but it requires removal of the plug and blocking off the pickup tube location in the accessory case.
The second photo is of the early tube. I believe the 150hp engines may benefit from the smaller intake tube to maintain mixture velocity with low compression.
The third photo shows the tapered spigots that are used on later 320s. The larger tubes (1 3/4")are the same size as used on the 360/540 engines. These sumps also have smaller runners than the 360 sumps.
Photo 4 is an IO360 sump with the larger, straight spigots. This is actually in use on my 320, so yes the 360 sumps will fit the 320 case. Make sure to get the tubes that are for the case as there are many different tubes and it could be a major ordeal to get the correct ones. Sense the 320 cylinders are shorter than the 360s you may need to shorten the tubes a small amount.
There are many different sump configurations and now days there are aftermarket sumps that may differ from the original Lycoming units, but that's another subject.
Anyone with additional information or variables is welcome to add.
Last edited:
