I'm trying to get some informed opinions on how bad my motor is (the truck a 1985 F250 6.9 Diesel 4x4 with auto trans). Essentially I knew something was wrong with the motor when it started the "intake chuffing" sound. It ran absolutely fine for a few months like that (I only use the truck sparingly as I drive a Taurus SHO for everyday use). I had just purchased a compression tester and was planning to do that over the holiday to confirm which side had the problem. But before I could do the test, I turned off the highway and noticed I was blowing some white smoke out the exhaust and the idle had gotten terrible. Pulled over and the reservoir tank was bone dry - so now I assumed I blew a head gasket.
I just did the compression test and all cylinders were around 420 psi except for one (rear drivers side) which was under 200. Pulled the valve cover on that side and discovered the pushrod wedged to the side of the rocker arm. Pulled the rocker arms and further discovered the wedged one was not only bent but also about 1/2 inch shorter than the other one. So the cam had been eating away at it (I tried to post a picture of the mangled rod but can't figure out how to).
In a nutshell I'm trying to figure out if this is worth fixing or if it's time for the junk dealer. The truck only has about 70k miles on it but the body is pretty rusty and I don't have a shop to work on it in. Plus if I have to replace the cam (not sure how to determine that?), I think that might be way more work than I want to do (I have already replaced both head gaskets a few years ago when one of the heads developed a crack).
I appreciate any feedback.
Thank, Scott

 

for posting pics, read this https://www.ford-trucks.com/forums/1...he-forums.html
in short, post them somewhere like photobucket and then link to them from here.

for your engine, it sounds like you have more than one problem going on here. i would start by trying to properly assemble the valve train on the offensive cylinder and retesting that cylinder.
if that cylinder is still a problem, try applying compressed air to that cylinder like a leakdown tester would do, and determine where it going.

 

I would start by pulling that head. Seems to me that you have a stuck / bent valve, which started the chuffing sound, and further lead to detonating the headgasket.

My fix? Find a 7.3 in the JY snag the heads for exhaust valves and rockers ( or just pull the rockers, but if its an exhaust valve thats burnt / bent broke might as well get them too) and haul em into a machine shop. I had my 390 heads done up for $350, if the engine only has 70k i would definately spend the money on it.

I would check the cam to be safe, however i doubt there is anything wrong with it, you may need to change a lifter if the bent pushrod chewed on it though.

Great time for a regrind on the cam if your looking for a little more oomph, and same for studs if you ever plan to turbo.

 

Image of destroyed pushrod:

 

i just read this on oil burners and thought about your pic when i read it.
just in case this comes in handy for you/is in fact related to your issue:

"the oil cooler bypass valve stuck closed and jacked the oil pressure sky high and caused the pushrods to go through the rockers "
that happened apparently to a member there called "goose" who had just installed the "torque cam" he removed the cam,put the stock back for diagnoses purposes,then i guess he found the issue.
anywho,just in case.might want to check it out,to make sure it doesn't happen again if you do repair the engine.
why then though,would it have only happened to one rod if this was the trouble though?.........but better to be safe than sorry i suppose.