Ok... Pulled valve cover... Sitting there making itself too obvious is the push rod closest to the front of the vehicle just sitting loose. I picked it up and noticed it's clogged... put a piece of straw down the hole and blew it out. Now clear.
Tried putting it back into place. Basically I loosened the 1/2" bolts on top of the rocker arms and placed the bottom of the push rod into the socket I could see down in the bottom of that "well"... and the top of the rod under the dimple in the rocker arm.
Well, when I retightened the 1/2 inch rocker arm bolts, the rocker arm now holding that rod is noticably higher than the others. Don't want to crank it til I get a handle on what's up... so I loosened the bolts and am scratching my head.
How would this thing just pop out, what does it push on, could that thing that it pushes on be frozen etc...
First off, the plugged hole wasn't what caused it to come out, at least not immediately. The hole only allows oil to move up from the hydraulic lifter to the rocker arm. If there was no oil getting through the rocker will wear. Did you carefully examine the rocker arm when you had it off? Did you check to see if the pushrod was bent.
Remove the nut holding the rocker arm on. Remove the pushrod and lay it on a flat surface like a table top and roll it. It will be obvious if it's bent. Look at the ends. They should be nice and shiny with no lines in them. if you see lines in one end look at the corresponding part on the rocker. Now look at the rocker arm. If I'm not mistaken it should be a ball type pivot. Look at the wear surface of the pivot and the rocker arm. It should be nice and smooth. If it's scored with lines showing in it it's worn out. Look carefully at the bottom of the rocker and make sure the bottom isn't broken out of it on one side or the other. Don't concern yourself with why it doesn't look right when put back together until you've determined why it came apart. I suspect this engine was noisey before it started missing. That's the time to start looking for these things.
Here's what I would do. Once I've confirmed that the cause is rocker and pushrod worn or broken I would of course replace them. I would then remove the rest of them and inspect them in the same way. You did right checking for the pushrod to be open, now check the rest of it on the other 7 valves. Check for scored pushrods, rockers and pivot balls. Now when re assembling, you need to know whether these are adjustable or not. I can't remember what those stovebolt 4's are. Some rockers of that type are made to have the nuts tightened until they bottom on the stud and torqued down. Others need to be adjusted. You make sure the cam for the valve you're working on is in the closed position. Tighten the nut until you have just removed the slack. Do the same on all cyl. When done start it. One at a time back them up until they start to clatter. Tighten until the clatter just stops. Slooowwlly tighten 1 full turn from there, allowing the engine to stabalize as you tighten it down. It has to bleed down the hydraulic lifter. You should refer to a manual to determine wether or not they're adjustable, but an indication would be the presence of a lock nut on the rocker usually means adjustable and a rocker stud with a shoulder on it suggests non adjustable. Steve
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