Valve head coming out?

wore out head i had this happen once on my Detroit

 

How far did it make it after overhaul? And does the driver know how to drive?

 

Question 1: No
Question 2: Maybe
Valve heads broken off stems often comes from piston contact.

 

Looks like that was driven a while. If one broke off the head beating around in there could catch the other three.

 

Is it always and only on # 4 ?
I am thanking something in that rocker bridge ? what ever it is called assembly getting out of place. Smacks the valve to the piston. Oil pressure is good and rocker shaft is not upside down?

 

If it were out of time, one would think it would cause similar damage on all 6.

I was leaning towards valves too tight but if they're tight enough to allow piston contact a truck driver would have been whining about lack of power for sure.

Wondering if there's an issue with the jakes? Pushing the exhaust valves open at the wrong time.

 

Detroit’s are famous for being a tooth out causing a valve to drop. They will actually not run too bad but most will say it didn’t pull like it used too. I almost bet they are not using the tool to hold the gear, cause looking at it as long as they don’t push the gear out no way it can get out of time. I can’t tell you how many times I have heard that.


One way to be sure is find true top dead center of any clyinder. Mark dampner rotate the engine to base circle of Injector lobe on cam. Set up dial indicator at 0 rotate engine in direction of travel to TDC compare lift of injector lobe to spec in manual. Depending on what cam it has etc. that’s the only way to know without pulling the cover and turning however many rotations to line marks up. A hunting tooth set up will not align every circle.

I also have never seen one drop a valve like that that didn’t get the crank. I bet the front main was a ##### to get in wasn’t it