Lycoming IO-540 Oil Pump flow rate?

[1001001]

I have searched all over for information on the oil pumps without success. Does anyone know the design oil flow rate of the pumps installed in Lycoming engines, especially the IO-540? Any information on the required oil flow rate for proper lubrication in the various engines?

[lr172]

Originally Posted by 1001001

I have searched all over for information on the oil pumps without success. Does anyone know the design oil flow rate of the pumps installed in Lycoming engines, especially the IO-540? Any information on the required oil flow rate for proper lubrication in the various engines?

doubt there is a spec for oil flow volume. As long as your relief is bleeding off oil (i.e. maintaining set oil pressure), you have adequate flow. When the relief ball stays closed and pressure begins to drop, you no longer have adequate flow. You are allowed to have a pressure drop at idle, as flow volume is directly tied to RPM and pump can't always produce the necessary flow at 700 RPM.

Larry

[1001001]

Originally Posted by lr172

doubt there is a spec for oil flow volume. As long as your relief is bleeding off oil (i.e. maintaining set oil pressure), you have adequate flow. When the relief ball stays closed and pressure begins to drop, you no longer have adequate flow. You are allowed to have a pressure drop at idle, as flow volume is directly tied to RPM and pump can't always produce the necessary flow at 700 RPM.

Larry

Given that the pumps are positive displacement (I assume), there should be a fixed flow at a given speed. Pressure will vary based on the system resistance to that flow, and then the relief valve will control to a set pressure. I guess what I'm looking for is an idea of the minimum flow necessary for adequate lubrication for rotating the engine.

My purpose in looking for this info is I want to size a gear pump to act as a pre-oiler (I know there are already commercial pre-oilers out there, but I just want to size a pump to do a periodic oiling of an engine not in use and don't want to buy a whole airworthy system).

I guess I could just buy a cheap gear pump, hook it up, and see if it makes pressure when run by a drill motor or similar. Don't want to waste money buying a pump that's too small.

[lr172]

Originally Posted by 1001001

Given that the pumps are positive displacement (I assume), there should be a fixed flow at a given speed. Pressure will vary based on the system resistance to that flow, and then the relief valve will control to a set pressure. I guess what I'm looking for is an idea of the minimum flow necessary for adequate lubrication for rotating the engine.

My purpose in looking for this info is I want to size a gear pump to act as a pre-oiler (I know there are already commercial pre-oilers out there, but I just want to size a pump to do a periodic oiling of an engine not in use and don't want to buy a whole airworthy system).

I guess I could just buy a cheap gear pump, hook it up, and see if it makes pressure when run by a drill motor or similar. Don't want to waste money buying a pump that's too small.

crank and rod journals/bearings are designed to have the clearance filled with oil. The designers determine the pressure necessary to maintain this. I am sure there is a flow requirement given the volume that the oil must fill, along with designed bleed amount to meet the pressure requirement. I have no idea what that is and have never seen a spec, though I am certain there is one for each pump. Highly doubt lycoming would share it though.

If you are just rotating the engine via the starter (appx 300-400 RPM) for a minute, it shouldn't require much oil flow to protect things. Most engines are started 1000's of times with no positive oil pressure for a few seconds at idle RPMs.

If you are just pre-oiling, there is no flow requirement. Just run the pump long enough to fill the filter, cooler and galleries. I would be more concerned that the pump could produce enough pressure to get the oil through the system. If it were me, I would use air. Make a jar with two tubes. One goes to compressed air source, other goes to oil gallery plug. fill the jar with oil and deliver 10-20 psi of air. I do something similar to bleed the brakes.

If the engine got a proper lube when assembled (assembly grease, etc.), it should have no problem cranking for 30-60 seconds dry as the oil pump fills the system. I recommend cranking with the plugs out until oil pressure is developed.

[1001001]

I just want to oil all bearing surfaces *before* rotating the crankshaft, to ensure all surfaces are coated periodically. Probably pre-oiling with a gear pump (which should not be limited in pressure) will be enough. I was just hoping to get enough information to select a gear pump that would deliver enough flow to generate a system pressure in the normal operating range.

[Robin8er]

Lycoming has a published pre lube procedure. It's not particularly difficult. As previously mentioned, the engine should have important parts pre lubes with grease and stp/oil to protect it during the first start.

[lr172]

Originally Posted by 1001001

I just want to oil all bearing surfaces *before* rotating the crankshaft, to ensure all surfaces are coated periodically. Probably pre-oiling with a gear pump (which should not be limited in pressure) will be enough. I was just hoping to get enough information to select a gear pump that would deliver enough flow to generate a system pressure in the normal operating range.

surfaces should have been coated with an assembly grease. It is a light grease and will not run off like oil. If this was done, it can sit for years without that grease running off the surfaces like an oil will.

Larry

[1001001]

Originally Posted by lr172

surfaces should have been coated with an assembly grease. It is a light grease and will not run off like oil. If this was done, it can sit for years without that grease running off the surfaces like an oil will.

Larry

This is not a new engine; it is one I am storing after having been run. I have "pickled" it but I do not wish to trust that that lubrication will be enough after sitting a long time.

[lr172]

Originally Posted by 1001001

This is not a new engine; it is one I am storing after having been run. I have "pickled" it but I do not wish to trust that that lubrication will be enough after sitting a long time.

I would trust the pickling. Gravity takes engine oil off of steel parts within a few days, creating exposure to corrosion. The oils designed for protection do not do this. They are designed to cling and protect, not lubricate.

Larry

[Cayugarandy]

I use an engine prelube tank,like the one Goodson.com sells.I put all the oil I want in the engine,in the tank,and let air pressure push everything into the engine.Rotating the engine slowly will lube everything while pressurized.Not hard to build your own if Goodsons is too pricey.