BENT PUSHRODS IN 6.0
 

Our faithful 6.0 is having its topside revitalized after 200k of good service (better EGR, oil cooler, APR headbolts, cleaning the "black scum" out of everything.

As we were starting to put it back together, we became concerned about a number of posts on this site where the poster had suffered repeated bent pushrods. And so we became very anal about not wanting to do the heads all over again for bent pushrods. The key seems to be, and we do not recall reading this in any posts, is the Ford shop manual statement saying quite clearly that when installing the rocker arms and pushrods [B]THE DYNAMIC BALANCE ON THE FRONT OF THE CRANKSHAFT MUST BE POSITIONED SO THAT THE LOCATOR DOWEL HOLE IS IN THE 6 OCLOCK POSITION.[/B] When we did this, we noticed that all of the roller tappets seemed to be at their "bottom" or "relaxed" position, that is, not being pushed on by any cam lobes.

Could it be that if the crank is not in this position that the tightening down of the rocker arm assembly leads to bent pushrods?? :c::s:

Although that's probably the "right" way to do it, I've seen it done the other way and guys have tightened the heads down on the pushrods like that. It just opens up the valves. Not that it's the best way, but I have actually witnessed it done this way without issue.

The issue seems to be not having the pushrods sitting in there correctly, or the bridges not seated properly as well. Just installation error usually.

BENT PUSHRODS
 

Thanks, Mdub. Wondering if by having the crank mark at 6-oclock, with the roller lifters in their lowest position, if it might make it easier to be sure the pushrods are all the way into the cups and roller lifters? That seems to be a common diagnosis of bent pushrods, that they were not "properly inserted into the lifter cups and lifters"?

And if some of the roller followers are resting on the cam lobes, if that would cause the raised valves/compressed springs to mess up the torque readings as the head bolts are tightened?

These are hydraulic roller lifters, they will compress down and when oil pressure is up they pump up. it doesn't matter where the lobes are as long as you make sure the rods are seated, the problem happens whe you just drop the rod down the hole and assume it is in the lifter cup, you have to slide it in and then always push on it to make it "bounce" up and down a couple times, it will feel like it is on a tight spring meaning it will move slightly to let you know it is seated, if it gets hung up on the edge of lifter it will not move at all and be solid so you will know it is wrong.

Good info Bob. I never gave that any thought and I didn't pay close enough attention when I saw it done, but that would explain why no one I've seen do it has every bothered to rotate it to TDC or anything. I've also seen the rocker bridges not seated properly too.

Best bet is to rotate over by hand a few times to make sure nothing is binding.