About 435 hours since I originally overhauled it (straight from the junkyard). 30 seconds after the first run (no oil) I took it apart and put in new bearings. Then ran about 245 hours before my first blow-by got annoying (not as bad as the last), replaced O-rings with stock. Then ran about 180 hours through this overhaul.

In addition to patching pitted o-ring grooves, this time I also retorqued the tension bolts after letting it sit for a day or two. Seems the sealant (Hylamar?) squeezes out gradually and probaby the teflon-covered O-rings take shape.

This whole project took longer than expected. Of course building a sand/bead blasting box  and beadblasting the water passages in the rotor housings cost me a couple of extra days. Then there was the engine mount...

Finn

Russell Duffy wrote:

Inner o-ring burned 3/4 way through. Still really don't know why. Chrome cracked around sparkplug. This time I filled the pits on the bottom of the o-ring groove with JB weld and used teflon-coated o-rings. Hope it holds up!

 

You've got several hundred hours on this engine don't you?  Was it rebuilt when you put it in the plane, or just used as you found it?  

 

Rusty