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Hello folks, so once I started taking stuff apart I realized the rocker arm carrier for cylinder #5 has broken at the most narrow part around the head bolt. The back side stud has sheared off completely and the stump is 1/8 down in cylinder head. I found the spacer but ball baring is nowhere to be found.
Can I get this bolt out or new head tim?. Can I just replace the rocker box?
I bought the whole rocker arm assembly and it looks quite a bit different, as the metal is the same thickness on the whole carrier, whereas the old had steps in it and was thinest at the head bolt, which was torqued like a lug nut. Any idea if this makes a diff?
Thanks
Tim
If you've got rocker issues on two cylinders, IMO you have a decision to make about that head coming off.
Replacing one rocker plate with one stud release might have been doable.
I was going to ask you to check if the secondary bolts on the wings were tight. While it's the studs (in your case) what holds the entire rocker plate down, those secondary bolts keep the rockers from flexing. So if those were not tightened, you have the potential for the rocker plate for fatigue failure. Or over tightened, shearing off.
If the bolt is sheared into the rocker box, it actually may be able to unscrew it with some care. If the Rocker Box has to be replaced or come off, so does the head.
Thanks jack,
Thanks Jack just one valve (#5), and I think I can get it out, not tremendous amounts of torque on those bolts. But I am confused about the middle stud.what are the torgue specs for that?
I would first try just moving the broken bolt with a center punch, rotating it counter clockwise. I’d rather not have metal chips generated. But if it won’t move, the way to bore a hole in the broken bolt is by getting a left handed drill bit, from like McMaster. Often by drilling in reverse the broken bolt comes right out. Again, I’d try like hell to move it out without drilling.
Since the rocker box is aluminum, even a 1/4” diameter cylinder super magnet may grab it enough to spin it out. I’ve done that.
Most people would not just remove one stud nut, they would want to pull the head, and replace the gasket due to the worry that you will never retain integrity of the gasket. If those are ARP studs, they torque to 210 lb-ft.
This morning I am ready to wrap this up. The intake is still attached and the exhaust side is completely broken off. Exhaust valve bridge is fine and I can reuse it. . If I remove the head stud (not great i know) and take the whole carrier off should everything just bolt right together? I bought the rocker arm tool from freedom racing but am unsure how to use it or if in my situation it is even necessary. The valves on the exhaust side are no longer compressed. Is this an issue? Also I ordered new push rods and even though the old one only has a nick in it it is not bent and the new ones are the short ones. Can I replace only one push rod that would be shorter than all the others? Thanks in advance. Tim
You can mix the pushrods, interesting they reused the old, original ones. I'd never reuse a pushrod that had a nick in it. Some might say it's best to put in the shorter ones, FYI.
I'm glad you understand the risk of taking one head stud apart, and if you have more than one bridge you are flipping, still only do one stud at a time. Some have had success, some have not. It's a risk. The tool goes on the two valves that the pushrod and rocker service, compressing them for room to install the pushrod when dealing with all of this assembled.
But before you do all the work, you might want to buy a 5.5mm borescope from Amazon to attach to a smartphone so you can see if the valves have hit the piston. Check the injector tip diameter. You need to figure out why all this happened.
Thanks really for walking me through this Jack. I just ordered the boroscope, I might need directions on that procedure as well.
What happened, which I did not mention before, was that I was towing about maxing my stated weight and although I had this truck for a short while I had never used the "truck/tow" button for some reason. I had more weight than I have ever towed and it felt a little heavy so like a dumb *** I used the button. All was fine until my last turn going home and the truck downshifted unusually on. I might have been going a little fast for that. I think thats where I did the damage.
After that it drove fine I did not notice the thumping until later on. I closely monitor temps and pressures habitually and saw nothing even after I noticed.
You may have over-rev'd at that point, a valve not closed as quickly as it should have and the lifter reacting to the empty space, the "lifter pump-up" situation. That would cause a piston hit. IF that is so, the valve stem could be bowed or the valve head bent.
The borescope check is easy, with the injector out the scope just down the hole and you see if there are impressions on the piston from valve contact.
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