Engine logs for modified engine?

[airguy]

I have a 115TTSN engine that came to me as an IO360B1B, and I've got the logbook for it.

I've modified it considerably, changing the starter, putting on a cold-air sump, a backup alternator, and removing the engine-driven fuel pump. Obviously this is now an experimental engine that will never go back to its "certified" status. My question now is, does it really matter what I write in the engine log as long as it describes accurately what I've done? My thinking was something along the lines of "Engine reconfigured by addition/change of xxxx" and list all the changes, and sign it off myself (non A&P). Is this kosher or do I need something else?

[Kent Ashton]

You don't HAVE to write up these changes or even sign what you wrote but it is nice for a future owner to have the history of the engine. You could sign as "Builder" for now. Later "Repairman" when you get the Repairman's Certificate

[SHIPCHIEF]

What Kent said seems correct to me;
However, you need to identify the engine some way when you register the aircraft.
I built my RV-8 with a Mazda rotary, so I had to name it and install a data plate on the engine.
After 16 hours of flying that combination, I decided to go Lycoming and joined IAC to do aerobatics. I got a sweeet !! deal on an IVO-360A1A out of a Brantley helicopter. 100 SMOH.
Same as you, many changes: new Superior sump, AFP injection, aircraft gear case, Oil fill tube, feather weight starter etc etc.
I logged these in the original engine log, verified the oil pump AD was complied, and installed a new crank gear just in case there had ever been a sudden stoppage that hadn't been logged.
I then re-named the engine by preceding the model with (X)
(X) IVO-360A1A
That satisfied the FAA when I updated the aircraft registration form, which seems to be the local interpretation for engine and prop changes.
It should serve the future, as the correct IVO-360A1A specific parts that remain can be sourced as required.

[Jesse]

I agree. Just write what you have done. It would also be great to include paperwork for the parts you have bought, especially if they are 8130-3 forms.