Engine/Transmission (1994 - 1998) bent pushrods: why?

[Bug1]

Replacing headgasket on my 96, I discovered that at least 3 of the pushrods were bent to the point of rubbing on the sides...



Why would this happen?



Truck is relatively new to me, but previous owner did some stuff:

head replaced 20-30K miles ago

heavier valve springs were installed at some point along with a rambrake

GSK & #11 plate are only performance mods...



I dont see anything else wrong so I will probably just replace them. . Should I do all 12 or just the ones that are bent?



Thanks in advance...



-Zach

 

[SRadke]

Do the ones that bent have anything in common? Intake, exaust? I would replace them all as a set.



-Scott

 

[Bug1]

both intake and exaust on the rear cylinder, and only the exaust on the front. I havent looked at all the others really closely yet as it was getting dark last night...



I did some searching and i read about people not getting the pushrod properly seated in the lifter when doing valve springs and other top-end work... I wonder if this was the case as my truck has heavier springs installed to go withthe exaust brake...

 

[Redram 1]

I would say who ever put the head on prolly did'nt have them in correctly,cause you can put them in,but they wont be on the tappets right.

 

[CumminsPower98]

I have had them get sideways (not seated on rocker) on the rear cylinder where it's hard to see and started tightening them down but never had one bend. Might have been something like that. I would replace only the bent ones, it would be way over kill to do them all if they are straight IMHO.

 

[Joseph Donnelly]

Definitely do a valve job while the head is off. The valves may have gotten tweaked a bit, and pitting on seats and valve faces is also common.

 

[EGaskamp]

When i had my truck in the shop i found out that mine were ben also. i replaced them all and i have no problems now. i guess after 200,000 miles they just gave out