Cracked 973-383 exhaust after just 33hrs

That doesn’t look like a factory welded nipple on a 33 hour pipe. Manufacturing defect and work on a better propeller balance is needed.

These types of breaks usually happen for a couple of reasons. Either a poor weld job, stress on the pipe from the exhaust outlet to the muffler and it's possible it has something to do with the metallurgy on that particular pipe. Plus if there was some stress higher than normal vibration could add to the issue. I've seen numerous breaks over the years. Some have been re-welded and some replaced. It may have been caused by the weld on the EGT probe.

Roger Lee wrote:

These types of breaks usually happen for a couple of reasons. Either a poor weld job, stress on the pipe from the exhaust outlet to the muffler and it's possible it has something to do with the metallurgy on that particular pipe. Plus if there was some stress higher than normal vibration could add to the issue. I've seen numerous breaks over the years. Some have been re-welded and some replaced. It may have been caused by the weld on the EGT probe.

Thanks Roger,

I will double check DynaVibe measurement and then when I install the new exhaust, will triple check that there are no stresses.

I agree this is from the weld at the EGT probe nipple. Typically, the EGT nipple is welded around the circumference of the nipple itself, reducing the heat affected zone greatly. The lager circumference of this weld is also in the bent elbow of the pipe, and the bending itself stresses the metal.