Tell me this noise isn't what I'm afraid it is.

[Old Henry]

Originally Posted by bobH

I'll offer a WAG... based on events as they happened on my own 47...
burned piston(s). I had problems with pre-ignition/pinging, and eventually found three pistons with holes on top, at edge, down into the ring-lands.
With heads off, easy to see on top of pistons.
Oh, the fun

That is certainly a possibility since, just a couple of weeks before the noise started, I put my old Stromberg 97 carb back on in place of the Holley 94 I'd been running. Then after the noise started I checked the spark plugs. They were a bit lighter than tan, more toward white, so I checked the jets in the carb and found that they were the .44's I'd put in to climb Pike's Peak and probably too lean. That's when I put larger ones in hoping it would stop what I thought was just premature detonation but it didn't. Maybe the damage was already done.