Here's a piston clock I made for my old man a while back. I made a second one to keep for myself. Thought you all might like it.
He has restored 2 seperate 1969 American Motors AMX's to beautiful numbers-matching condition. One of the 390 V8's had cracked heads and bunch of unusable rusty internals, so I ended up with the scrap because GRM. This is after some light sandblasting.
Tack welded the con-rods to the piston pins.
Couple coats of clear to keep the rust away
Cut some rings out of plastic with a hole saw. I recommend wood for this instead.
This is a woodworking clock insert, which are just a few bucks and come in standard hole sizes.