We got new cams for our 2005 4.6 3V (100K miles on it), and it ran great for 200+ miles, then a rocker broke, and a spring came loose. Brenspeed says the cam is 100% compatible (nothing special required) and not the cause of the problem. I sure hope they are right. At the time code reader reported only "problem with cylinder 7" and this was of course where the rocker was broken.

Talked to one mechanic on the phone, the thinks we need to take the head off to check the cylinder and value. Is this really necessary? My guess, and I'm no mechanic, is the cam was a bit much for the old rocker and it just broke, releasing the spring. Pressure in the cylinder would have pushed the loose value up and out of harms way, I don't see any reason for it to bend unless there was a timing issue. But it ran perfectly fine for a couple hundred miles, why would a timing issue soundly pop-up.

Any thoughts or help on this (especially from people who know this stuff)?

 

https://photos.app.goo.gl/awiKxEvKDBqvbEvm7

 

Now my son tells me he used a scope and piston and cylinder have no signs of damage; can't get around to see the value

 

take a compression test. You will know if the valve is ok. I would suggest all new springs with the new cams.

 

compression test is a great idea