Anyone ever hear of a camshaft pulley sheering off of the cam?

[millera1984]

I have a 2002 F225 4S with about 1100 hrs on it. It always runs super smooth and reliable, has never had any hickups or issues what so ever. But, I was running it at about 5300 rpms (which I do all the time) and all of the sudden it shut off without any warning. I originally thought the timing belt had broke since it was cranking really fast, but when my mechanic took the timing cover off the belt was fine, but the port camshaft pulley had sheered off and was just laying there inside. As I am waiting for a new pulley to come in the mail, the mechanic hasn't found any other damage or potential causes.

Has anyone ever heard of this, or does anyone know what may have caused it? The cam is still moving freely, so it didn't lock up or anything.

[ausnoelm]

be pretty rare to not have the piston bend the valves when it was out of time, but you never know I guess, but "spinning really fast" sounds terribly like the valve stems are bent and stuck open, causing no compression.

[rodbolt17]

lucky you.
that is a clearance motor.
means if the belt or a chain breaks pistons wont whack valves.
you do need to remove the cam cover and check the chain and tensioner on the other cam.
best I recall its a plastic gear so failure is possible.

also carefully inspect the belt tensioner for damage. belt whip due to a faulty tensioner could but undue stress in that sprocket.

chain and chain tensioner is part of routine maint.