Simultaneous EUP and lifter failure help me think it through.

[Trumbull_welding]

Good afternoon, gentlemen
I’ve got a real mind twister here. 2007 Mack tractor came in with a misfire initial computer diagnosis led to EUP wiring we pulled and inspected the EIP wiring and found no issues then proceeded to pull each individual EUP and found number 2EUP had failed clip on the EUP was dislodged, and there was damage to the plunger bore it was cracked and disformed we pulled all the EUP cups inspected and cleaned and found light wear on the top sides and bottom sides of the cups. Nothing major lubricated and reinstalled the cups reinstalled EUP’s and replaced number two. Upon start up after replacing number two still had a misfire and replaced number two injector. After replacing the injector the truck ran smoother. But with the intake off, you could hear a thumping sound removed the valve covers again and upon inspection of the valve train found number three Exhaust had a large amount of play. Removed the rocker shaft and number three exhaust push rod and found the H clip was dislodged, and the lifter was below the clip. I’ll attach pictures of the EUP excessive valve lash and inside the lifter boar. Looking to try and figure out the reason for and explain the failure. I’m attempting now to write out the different strokes in firing order to figure out if the EUP lock up and damage could’ve somehow caused the. Lifter damage as well a little over a year and a half ago the engine got a cam and steel lifters trying to wrap my head around this one.

 

 

[steeler]

Probably coincidence. Couldn't tell you how many cam failures I've done and found an eup with the dangling spring. H ring/lifter failure had nothing to do with the eup coming apart imo. 

[Joey Mack]

I'm thinking an engine overspeed is possible. Pulling the event logger info should show that. Steeler.. i respect your thoughts... I am well versed in these failures, but wont ever see it all..  🍻