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Old 10-12-2013, 01:40 PM   #1
Olustee bus
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Default Broke a rocker arm stud - need some good news

My 327 has a broken rocker arm stud. I was driving along at a good speed then slowed down in a small community. Heard a knocking, it quit, started back, quit started back and I pulled off the road.

A friend of mine last week said he heard a ticking like a hydraulic lifter was leaking. I can't hear good and I have never heard it. I was turning on the carburetor and did not hear it.

Got it home and pulled the cover, Saw a rocker arm out of place, I just figured it just fell off the valve and pushrod. I went to straighten it and picked it up.

The arm beside it is very loose.

I know I got to take off the head and have a new stud put on.

I assume I need to replace the lifter. Do I have to replace all the lifters.?

I hope that is all I have to do as I am not prepared to pull the engine.

What do you think?
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Old 10-12-2013, 02:00 PM   #2
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I know I got to take off the head and have a new stud put on.

What do you think?
I think you can drill the old stud and tap it for a 5/16" bolt. Slip a socket over the broken stud. Get a bolt/washer the appropriate length, grease the washer, run the bolt in the stud and jack it out.

If the stud shows a clean break, you probably had a bad stud. If the rocker arm cut a notch in it and that weakened it until it broke, you probably had either a cam going down or more likely a worn rocker nut that backed off and you continued to drive.

Inspect the top of the valve stem in the respective cylinders and make sure the top of the stem is square. If it isn't, you get to pull the head off and have the valve squared up.
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Old 10-12-2013, 02:17 PM   #3
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It is broken down below the top of the stud hole. It is a very clean break. Looks perfectly flat. I hope I can extract the stud.

I will check the rods.

What concerns me is that the rocker arm next to the one that broke is very loose also.

Should I replace the lifters?
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Old 10-12-2013, 04:36 PM   #4
MikeM
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It is broken down below the top of the stud hole. It is a very clean break. Looks perfectly flat. I hope I can extract the stud.

I will check the rods.

What concerns me is that the rocker arm next to the one that broke is very loose also.

Should I replace the lifters?
If the rocker nuts have lost most of their prevailing torque feature, that could be the extent of the cause of the problem. Rocker nuts backed off.

I wouldn't replace any lifters until after you repair the stud and see what's really wrong. I've never seen a noisy lifter cause a broken stud but there's a whole lot I haven't seen. I have seen loose rockers cut studs on one side and ball off the valve stem and rocker arm interface.
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Old 10-12-2013, 05:29 PM   #5
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I placed the rocker arm on the valve and push rod and put the stud top, swivel and nut on (nut has not been touched) and the top part of the stud would not meet up with the bottom part of the stud by a pretty good margin. I am thinking maybe the bolt was adjusted too tight. However, it ran good. It would buck some at slow speed but the accelleration was great.

I think your idea of just putting it back together and see what happens is a good idea. It may be that the one that broke was way too tight and the one that is loose is just not tight enough.
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Old 10-12-2013, 05:36 PM   #6
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If it is a hydraulic cam / lifters, the tight one is probably just pumped up (and is why it is "too tight").

The loose one may have a stud that is pulling up, or wear somewhere in the valve train, or a nut that did not hold it's adjustment position.

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Old 10-12-2013, 06:29 PM   #7
MikeM
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Originally Posted by Olustee bus View Post
I placed the rocker arm on the valve and push rod and put the stud top, swivel and nut on (nut has not been touched) and the top part of the stud would not meet up with the bottom part of the stud by a pretty good margin. I am thinking maybe the bolt was adjusted too tight. However, it ran good. It would buck some at slow speed but the accelleration was great.

I think your idea of just putting it back together and see what happens is a good idea. It may be that the one that broke was way too tight and the one that is loose is just not tight enough.
If you get hydraulic lifters either too tight or too loose, you will have either a miss or a click. Too tight won't pull a stud but it will make the engine have a dead miss.
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Old 10-12-2013, 06:30 PM   #8
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Quote:
Originally Posted by Olustee bus View Post
I placed the rocker arm on the valve and push rod and put the stud top, swivel and nut on (nut has not been touched) and the top part of the stud would not meet up with the bottom part of the stud by a pretty good margin. I am thinking maybe the bolt was adjusted too tight. However, it ran good. It would buck some at slow speed but the accelleration was great.

I think your idea of just putting it back together and see what happens is a good idea. It may be that the one that broke was way too tight and the one that is loose is just not tight enough.
with all due respect, you need to bone up on valve trains and how they work....read the sticky on valve adjustments....you are probably working with hydraulics?....also re read plastic man's post... may have to hire an expert or you could make things worse....good luck....
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Old 10-27-2013, 01:11 PM   #9
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Wtih the help of good friends, we removed the stud and replaced it. I added roller end rocker arms and new pushrods. Checked the compression in the subject cylinder. Pumped up to 180. I have 12 to 1 pistons.

Tuned it, got rid of a vacuum leak.

Man, does it run good. Sounds the best it has ever sounded.

Click the image to open in full size.
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Old 10-27-2013, 01:11 PM
 
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