Push rod unseated?

[Mr. Tarkanian]

So I've had a 91 explorer sport with a pristine body and interior sitting in the barn for 18 months because I thought it had a bad piston. Anyway, started breaking the motor down last night, and after I got the left bank valve cover off, I found the #6 cylinder front pushrod had fallen down into the lifter valley, completely unseated from both the rocker arm and the lifter. The rocker arm had slid a couple inches forward on the rocker shaft. That particular lifter seemed to have plenty of pressure. How the heck did this happen? I put it back together, and it seems tight, but whats the chances of it happening again?

 

[94Reborn]

I have a 4.0 with no compression in cylinder 5, and I'm debating tearing into it or just swapping in a new motor. My mechanic thinks it could be as simple as a pushrod, but why would a pushrod fall out without a bad lifter right? Did you put your back together, and what was the result?

 

[Explorin94]

Why not try putting it back where it goes and seeing what happens. But before you do make sure that it is not bent. Usually a pushrod will come out if the motor has been over reved. If it does the same after you have put the pushrod back in place check the lifter and well as the rocker arm for excess wear.

 

[94Reborn]

Yea I'm going to at least take a look, but I was wondering why it would come out. I'm not sure how abused the motor was before I bought it. I've decided if its a lifter im scrapping the engine as its not worth taking the head off, but if its a pushrod or a rocker arm I'll replace them. I paid 200 for the engine so its not a total loss at least.