Hyundai V6 G6EA engine damage

Problem.  We were asked to help diagnose damage in the combustion chamber of a Hyundai V6 G6EA engine. Vehicle was in for a 40,000 kms service and drove in without a noise. During the test drive it developed a severe engine noise. Heads and two pistons were pulled  to reveal damage.
The chamber had the usual indentations of a foreign body rattling around between the head and the piston. Under a twenty power eye glass, I could not identify the item from the marks. Usually a thread shape appears. Checked all of the butterfly valves for missing screws..found none. But the Foreman shook the exhaust manifold and retrieved several pieces of egg-shaped and ball bearing shaped particles measuring from three to six millimeters long. These were just rattling around in the upper regions of the exhaust manifold immediately above the cat

Cause:  The irregular shaped items matched missing weld material from the upper section of the cat material. This is a mesh that is welded in place some 150mm below the exhaust manifold face of the head. This has been drawn up into the exhaust port during valve overlap and happened during the service test drive.

Cure: This is a Factory issue and nothing that we can change. BUT we can be aware that several catalitic convertors are dumping material into engines, (6VE1 Isuzu, Nissan X-Trail, and now the Hyundai above). You all know what it sounds like and now we can but wonder where else future engine damage can come from.
Good news for the workshop and for the owner though.
Hedley James
Ph 03 9372 3111