Piston Met Valve With New Timing Belt

1996 B4 got a new timing belt with all new timing parts only about 2k miles ago and has been running fine and now the #3 piston has hit a valve and broken broken a lifter. The motor turns over by hand only about a quarter turn before it stops, I’m assuming from a piston meeting another valve. Any ideas what might have caused this suddenly happen? I’ve never driven it hard as the reason I bought it was for the mpg. I don’t know if it makes a difference, but I’ve recently started down shifting when slowing down to put less strain on the brakes.

Downshifting isn't a problem.

Is the belt still tight?

You rotated the tensioner hub clockwise when you did the belt?

Is the cam bolt tight?

All great questions.

And I agree, downshifting, even hard, would not cause it.

I bet it’s also a failed tensioner for whatever reason.

Cam can be torqued to spec, but I’ve seen the sprocket move. I ignore the factory spec and go to 50#s.

-Todd

I'm slightly confused at the comments here, i was understanding that if the belt skipped a beat in any way that most, if not all your valves get bent, unless its idle and it happened right as you turned off the key, why would it ONLY bend 1 valve?
Did you pull the cam off and check under the lifter? Seems that it might be head related and not the belt.
THe obvious thing do do here is put it back at TDC and see whats off, if the belt is where it should be, and only one valve is bent, its clearly not the belts fault and probably a gacked guide or a valve that almost snapped off due to random fatigue for what ever reason valves decide to randomly snap off.
Are you going to pull the head and have it fixed?
Also possibly a foreign contaminate made it past the filter and into the intake, OR a chunk of crap from the intake cake from oil and EGR mix broke off and ended up against the valve. If i had to take a wild guess at it, i would guess this. Its not the first time its happened to anyone.

What you say makes sense but the fact that he just did the belt made me jump to the conclusion that it's a belt problem.

Typically it's exhaust valves that get hit because they are closing as the piston is approaching TDC. If the belt skips the valves are going to be late. Seems unlikely that the cam is going to skip forward.

You're right though, if it happened while he was driving all the exhaust valves should be damaged.

He can't rotate the crank. It's either still hitting the damaged valve or it got past that one and it's hitting the next one. No way to tell from here. He's going to have to do some investigating to see where the crank is and post it.

Should be able to tell by where the pin hole in the pump sprocket is. How about it Marty? Where is the pin hole when the crank stops?

What was going on when it died? Driving, idling, shutting down, starting?

If you have a fractured lifter, It's time to pull the head. You or a previous owner did something wrong in regards to timing most likely.

I haven’t pulled the head yet. Will most likely be July before I get enough free time to work on it. Timing belt is tight. I was cruising down the highway at 60 mph around 2k rpm when the motor just suddenly quit. I put piston #1 cam lobes in the up position like for TDC, but could not find the TDC mark on the crank gear. If I had to guess, im betting the cam gear spun on the camshaft. But I cleaned it off perfectly and followed instructions to the tee when I torqued the cam gear to the camshaft. I know it wasn’t carbon crud getting into the cylinder since I had the intake manifold and intake runners completely cleaned when I did the timing belt. So what are the chances that I cracked the piston? Any chance I got lucky and just replacing the broken valve and timing issue will be all I need?

No way of knowing without removing the head. Then you'll have a much better idea…