Lycoming O-540 Engine model question

DKirkpatrick

DKirkpatrick

Pre-takeoff checklist
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DKirkpatrick
Hi,
Looking at a nice older Piper 235. Has a nice older Lycoming O-540 B4B5... If I should find a Lycoming O-540 A1D5 replacement engine, from a Comanche, can that go into the Piper 235? Can that engine be modified to the BRB5? Thanks in advance for the coaching.
 
DKirkpatrick said:
Hi,
Looking at a nice older Piper 235. Has a nice older Lycoming O-540 B4B5... If I should find a Lycoming O-540 A1D5 replacement engine, from a Comanche, can that go into the Piper 235? Can that engine be modified to the BRB5? Thanks in advance for the coaching.
Click to expand...

Why do you want to do this?
 
Thanks for your help with this. Will do my homework
dan
 
DKirkpatrick said:
Hi,
Looking at a nice older Piper 235. Has a nice older Lycoming O-540 B4B5... If I should find a Lycoming O-540 A1D5 replacement engine, from a Comanche, can that go into the Piper 235? Can that engine be modified to the BRB5? Thanks in advance for the coaching.
Click to expand...

No this can't be done,, the rules governing the swapping of data tag prohibits it.
different engine requires an Approval of some sort. (STC, or Field approval)
 
The manufacturer can rebuild any engine to any configuration they choose and issue a new data tag.
 
Tom is correct as usual. Back before about '86 the factory would allow conversion of engines and provide a modified data plate for the "new" model engine. We had to submit to them a list of the changed parts. G & N was doing that several times a month. The straw that broke the camel's back came when we converted a pair of TIO_540-A2C engines to IO-540-M1A5's that were installed in a new Evangel aircraft. The parts change list was seriously long. Lycoming was really unhappy because they cancelled their order for Factory M1A5's because Lycoming union workers was were on strike. Not to be outdone we applied for and received an approval to do the conversions and modify the data plates under a process specification on the shop's FAR 145 repair station certificate. Penn Yan later received the same approval. I was there!
 
I once changed an O-320 from a Cherokee to a 172. Swapped the accessory cases and guts (fuel pump plunger) and prop flange bushings and probably a few other things. Used the IPC's and got permission from Transport Canada. One of their requirements was to remark the data plates as applicable and continue the logs (no swapping).

It was a lot of work, but was doable at that time. I would have to be convinced (a lot) to go through the hassle today, if it would even be applicable to the OP's models.
 
there is an STC to swap in the A1D5 engine, so you get the 250 HP instead of the 235 HP.
It can be done via an engine swap, or by changing the pistons in the 235 engine to those from the 250 engine,
 
I have done close to the same for a PA-25-235, Piper Pawnee, but under STC. The standard PA-25-235 engine is the O-540-B2C5 at 235HP fixed pitch. An STC changes the exhaust valves and piston to increase the engine to 250HP fix pitch. Everything else, to include carburetor, magnetos, etc., stay the same. The engine data plate is stamped O-540-B2C5-C-A1D5.

The A1D5 engine is the Comanche 250 engine, but you can't just hang an -A1D5 engine on the PA-25 without approval, normally done by STC.
There are two STCs, one to modify the engine, the second to approve putting the modified engine on that airframe.
 
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