What's new
Van's Air Force

Don't miss anything! Register now for full access to the definitive RV support community.

IO390 cylinders on io360 case?

emsvitil

Well Known Member
Will the IO390 cylinders bolt on to a 360 case?

I know internally the 390 cylinders have a larger bore, but do they have the same bolt pattern?
 
IO390 cylinders on io360 case

There are two types of IO-360, parallel valve 180 hp and angle valve 200 hp.
Goggle parallel vs angle valve, picture.
They are completely different in their construction.The angle valve weighs about 30 lb more, crankshaft has dampers and they are always fuel injected.
I believe the cylinder bolt pattern may be the same.
The machined internals of the case is different to accommodate the bigger crank and the angle valve system. There might be other differences as well.
 
Will the IO390 cylinders bolt on to a 360 case?

I know internally the 390 cylinders have a larger bore, but do they have the same bolt pattern?

All the original 390's built at Barrett were angle valve 360 models with bored case spigots and 580 jugs. I don't know all the case mod details, but I think the bolt pattern is the same. Call Rhonda.

Lycoming didn't develop a dedicated 390 case until later, and originally distributed them as kit parts only. The original kit case is for the small main bearing crank from the 360. Current certified and EXP 390's are large main.
 
All the original 390's built at Barrett were angle valve 360 models with bored case spigots and 580 jugs. I don't know all the case mod details, but I think the bolt pattern is the same. Call Rhonda.

Lycoming didn't develop a dedicated 390 case until later, and originally distributed them as kit parts only. The original kit case is for the small main bearing crank from the 360. Current certified and EXP 390's are large main.

Dan, I think I understand from this that some case modifications are required. So, if, for example my angle-valve 360 were in need of a top-end overhaul, I could not just simply bolt on 390 cylinders.

But perhaps, if my angle-valve 360 were to be fully overhauled, Rhonda and co. might be able to turn it into a 390?
 
Dan, I think I understand from this that some case modifications are required. So, if, for example my angle-valve 360 were in need of a top-end overhaul, I could not just simply bolt on 390 cylinders.

But perhaps, if my angle-valve 360 were to be fully overhauled, Rhonda and co. might be able to turn it into a 390?

That's how they built the early ones.
 
Back
Top