Lycoming O540

[vrooyeri]

Hi all. Just a quick question to those in the know. I'm in the early stages of overhauling my O540. It has a A1D5 designation which means it is rated at 250 hp at 2575 rpm. I don't have a prop yet so can still source an appropriate prop for the designation I have.

So here is my question: should I stay with the current designation or should I convert the engine to A4D5 to accomodate the compact hub Hartzell props? And if I then go there, should I then go for the E4A5 that delivers 260hp at 2700rpm?

Any views on this as I suppose prop availability will be be major deciding factor with some consideration for the additional 10hp.

Thanks

[Gerhard Rieger]

Check if you got the heavy crank, not all can go to 2700rpm

[rodsmith]

I may be wrong but I believe other than counterweight configurations the O-540 cranks are all the same for parallel valve engines, the IO-540 angle valve engine crank is heavier.

[rodsmith]

Hi all. Just a quick question to those in the know. I'm in the early stages of overhauling my O540. It has a A1D5 designation which means it is rated at 250 hp at 2575 rpm. I don't have a prop yet so can still source an appropriate prop for the designation I have.

So here is my question: should I stay with the current designation or should I convert the engine to A4D5 to accomodate the compact hub Hartzell props? And if I then go there, should I then go for the E4A5 that delivers 260hp at 2700rpm?

Any views on this as I suppose prop availability will be be major deciding factor with some consideration for the additional 10hp.

Thanks

It would be best to acquire or at least commit to a particular propeller. Then when doing the overhaul you can have the correct counterweights installed for it. Reminds me that I need to check with lycoming to see if 3-blade MT needs the counterweights on my B4B5 engine.

[Gerhard Rieger]

IO-540 C4 B5 have the heavy crank