I had a blown head gasket and decided to replace it. While having the heads off I took them to a machine shop to get them rebuilt. After re-installing them I drove for about 50 miles and stopped. After starting the truck again my truck started to make a ticking noice and my check engine light turned on. I took it to the dealer and they diagnosed the #6 cylinder miss firing. I drove it for about 400 miles with miss firing on that same cylinder. I made an appointment to have it checked out by the machine shop that I had the heads rebuilt at. I took it back to the machine shop and they diagnosed that the #6 cylinder exhaust valve was not closing all the way. A week later I took it back to have them fix the problem and they noticed that my timing chain was falling apart and loosing chain links. They took out the lifter for that valve and cleaned it out. They said that after doing that, the truck ran fine for about 10 minutes and continued to miss fire. What would cause the timing chain to break apart. Take a look at the pictures. Do you think that the timing chain was falling apart before or after the machine shop tried to fix it? It was not making any kind of front end noice near the timing chains during the time I was driving the truck. The shop is trying to stick the bill on me for a whole new engine rebuilt!
My truck is a Ford F-150, 1999, 4.6L, about 165K miles. I asked a mechanic if I needed to replace my timing chains and he said, if the chain guides aren't worn then they are fine. The pulleys are all lined up and not bent. Everything went on perfect. Not sure why the chain is like this. What do you guys think?
I removed the heads and re-installed them myself. Therefore, I installed the tensioners myself as well. I over looked all of my work and did everything correctly and can't see what went wrong. There has to be an error with the heads and how they where rebuilt. Don't you think guys? I'm having ford take pictures of what they find and document everything. Here is another question. After driving my truck about 200 miles I changed the oil. I did not find any metal shavings within the oil and wouldn't you be able to hear the chain breaking apart during my total driving time of about 400 miles?