`96 Quest cam broke

[pmkls2]

My sister has a `96 Quest that had a bad water pump so a couple of weeks ago she took it to a little redneck mechanic to have it replaced because I told her I didn't have the time to do it myself. The guy had it a couple of days when he called her and said that the van needed a new timing belt so she told him to replace it. after a few more days she hadn't heard from him so she called him to see what was going on. He told her that after replacing the water pump and reassembled the engine the timing belt jumped time. After having spoke with her about the belt he replaced it and reassembled the engine again and it had a funny knock type noise in the engine. He claimed it was from the engine jumping time and bending valves and that the engine now needed a head job. This is where the story gets messed up because I went next door to the Nissan dealer to ask if these vans had an interference engine and was told that they in fact do not. I told her this so she decided to have the van towed next door and have them tell her what was the matter. I personally spoke with the technician to advise him of the situation and that I suspected the other mechanic had broken something. Anyways to get to the point, the Nissan tech disassembled the front of the engine and found that the snout on the cam on the front head had broken off and the pulley was off-center as a result causing it to rub the backing plate and make a noise. This clearly looks to me like a human error, AND the tech next door agreed with me. HOWEVER he did not want to be involved in the matter as my sister wanted the other mechanic to pay for the repairs which amount up to about $1500. So when the other mechanic called him to see what the deal was this guy proceeded to tell him that it is possible for the cam to have broke on its own. I would just like to get some info of anyone has ever seen a cam snout break on a nissan 3.0 liter engine without human influence, because this is a $1500 question for my sister. I have never seen this type of problem on any car I have ever worked on, but I work on GM cars so an opinion from a Nissan tech would be helpful. By the way I have some pics at home that I can upload if anyone would like to see.

[NISTECH]

the"redneck mechanic" over tightened the timing belt. I had to deal with this once on a quest that had a belt installed at an aftermarket shop. the customer was concerned with a bearing type noise from the engine. what we found was the belt had been tightened so tight it ate away at the upper front main bearing giving the crank a hurrendous up and down free play when the belt wasent installed. at the heads where the cam shaft rides had eaten away at the head side of the cam bearing caps. since it was a machined into head bearing set up. it ended up needing a long block since it would have costed more to replace the crank shaft and rebuild the lower end plus replace both heads. the long block was the better deal.

I have yet to see a cam shaft break do to it but it is possible to snap it if over tightened. the reason the nissan technician does not wanna get involved is because it would be hard to prove 100% he did it. especially if you are not a regualer customer of the dealership you are asking for help from. He has no history on your vehicle in his records to show the car had been worked on before and no problems where ever noticed with it.

[pmkls2]

Thanks for the opinion that is all I was wanting. I can understand the disposition of the tech, because I feel the same way. In fact, I am a dealership technician myself (Cadillac) and I have had similar dealings with which I did not really wish to not be involved, including this ordeal. I just don't understand why he told me one thing and told the other guy something different, but more importantly I just wanted to know if anyone has in fact seen a similar occurence on that particlar engine. Thank you again for the answer.