Bent valve question for the experts

[custom10nut]

This is not with my truck, but I have a question about what it takes to bend valves. The reason for asking is a shop is using "another reason to get money out of me" and I'm not falling for it.
The engine ran fine, was timed, and had good compression when it went into them. They flashed the ECM to get it synced, and I went to drive it home. About five miles into the trip it hesitated, ran a little farther,and then cut out. We checked all electrical and fuel possibilities, but nothing. I had it towed back to them, and that's when the ho hum stories started. Long story short is that now they say that the valves are bent in 2 cylinders (4 cylinder eng), and "it must have been out of time". Checked it and no, perfect. My thought is the tech left something in there that was sucked into the two cylinders, and did the damage. Mgr says no.
Any thoughts from the Wizards?

[BILT4ME]

Originally Posted by custom10nut

This is not with my truck, but I have a question about what it takes to bend valves. The reason for asking is a shop is using "another reason to get money out of me" and I'm not falling for it.
The engine ran fine, was timed, and had good compression when it went into them. They flashed the ECM to get it synced, and I went to drive it home. About five miles into the trip it hesitated, ran a little farther,and then cut out. We checked all electrical and fuel possibilities, but nothing. I had it towed back to them, and that's when the ho hum stories started. Long story short is that now they say that the valves are bent in 2 cylinders (4 cylinder eng), and "it must have been out of time". Checked it and no, perfect. My thought is the tech left something in there that was sucked into the two cylinders, and did the damage. Mgr says no.
Any thoughts from the Wizards?

You need to advise year, make and model as well as engine size. Since you mentioned that it was a 4 cyl, it is obviously NOT in one of the C/K 10/20 trucks.

Also miles, and the reason it WENT to this shop. What did that shop do? Did they do a brake job? If so, then it's unrelated to what this issue is.

Some engines are "interference engines" and when they lose the timing belt, they become a boat anchor.

Also, when it happens, it is sudden, makes a HELL of a lot of noise and STOPS, not to turn over again.

Otherwise, the only ways it bends valves in two cylinders is if someone did something wrong, such as inappropriate valve adjustment, or a larger chunk of carbon came loose at high RPM and hit the head of a valve while the piston was on the exhaust stroke.

There are so many things it COULD be and so many things it cannot be.

Being out here in the digital world, WE will never know both sides of the story, only what you feed us. So, we will conjecture whatever we dream up based on your input.

It may be a Flaming Rainbow Unicorn for all we know........

I'm sorry for your loss.....

[truckster]

What engine? Why did you have the ECM flashed? How did you determine the timing is correct?