O-360-A4A conversion to O-360-A1A

[RhinoDrvr]

Hello all,

Is it possible on our experimental aircraft to convert a Lycoming O-360-A4A from a Cherokee 180D to a O-360-A1A with the hollow crankshaft to allow the use of a constant speed propeller?

I ask because I'd be interested in doing this as part of the next engine overhaul. Any idea what the ballpark pricing would be? Looking around it appears that a standard overhaul would be $15,000-$20,000 assuming a good core; what can I expect the conversion (if possible) to add to that cost?

Thanks!
Evan

[RV6_flyer]

Originally Posted by RhinoDrvr

Hello all,

Is it possible on our experimental aircraft to convert a Lycoming O-360-A4A from a Cherokee 180D to a O-360-A1A with the hollow crankshaft to allow the use of a constant speed propeller?

I ask because I'd be interested in doing this as part of the next engine overhaul. Any idea what the ballpark pricing would be? Looking around it appears that a standard overhaul would be $15,000-$20,000 assuming a good core; what can I expect the conversion (if possible) to add to that cost?

Thanks!
Evan

IF the crank is a hollow crank, plug exists in the crankcase, and accessory case will accept a governor drive adapter, it should only add the cost of the missing parts plus governor drive adapter. In other words, it should add a few hundred dollars for new retail parts.

See Lycoming Service Instruction 1435 to see what is involved to convert.

[RhinoDrvr]

So, the crank is NOT the hollow crank. The more I look at the docs, it seems the best option would be to sell the core and put the money towards a new A1A and constant speed prop.

[RV6_flyer]

Originally Posted by RhinoDrvr

So, the crank is NOT the hollow crank. The more I look at the docs, it seems the best option would be to sell the core and put the money towards a new A1A and constant speed prop.

With a SOLID crank, it would be better to sell core and find another.

I would expect a NEW crankshaft to set you back somewhere around $8K.

[659JR]

You can get new cranks for 4800-5000 and used when you can find them around 3600. The A4 crank would be worth about the same. I would guess if you could find someone to exchange cranks you would be looking in the 1000-1500 range to convert it over to the constant speed.

Jesse
Colorado Air Parts
970-874-7575

[mahlon_r]

you will also need to modify the crankcase nose/front bearing bore.
see info here: http://eci.aero/pdf/04-4.pdf
Good Luck,
Mahlon