Cast Iron Guides not Bronze in your OM614 Head

I was tooling along the highway heading home when I lost power. I had a problem with my turbo in the past, but this felt different. The engine was running really rough. I was lost to home so I pulled over and used a tow strap to pull the truck home.

For sure it felt like one of the valves was not working properly, so I pulled the valve cover, and sure enough, the exhaust valve on cylinder 4 was not working. Looking closely, it looked like the valve lifter guide had popped out. 

This engine was from Diesel Mercedes but it looks like their work is not quite up to snuff. Like I said, the turbo they supplied failed, and they sent me a new one and now the head is giving me problems. I thought about working on it myself but decided to tow the truck to my local shop.

They rebuilt the head, and when I picked up the car, halfway home the same thing happened.

THIS IS IMPORTANT: the folks who supplied by OM614a Turbo, used bronze guides when rebuilding the head. The tech at my shop said that the original head featured cast iron guides. So they got another head replaced all the seals, and installed cast iron guides. 

Now the engine works great and actually has more power than ever.