Rocker Arm Stud pulled out

[John3]

The Engine had been running fine. I went to start it, just to keep it lubed & running after a couple of days idle. It backfired, & ran rough as a cob. I removed the rocker arm cover. One of the # 6 Valves was stuck closed & the Rocker Arm Stud which was press fit in at the factory, had pulled out.
I tapped the end of the stuck valve with a wooden mallet, it moved slightly. But was still stuck. Sprayed with WD40, more tapping and then I gripped the valve stem with vice grips more WD40 & I rotated it. I worked the valve free. Can now move it in and out by hand.
I bought a threaded rocker arm stud. I think that may have been a mistake. Probably should have used a new press fit stud & held it in place with High Temp. Lock-Tight. Anyway I used a threaded stud. I tapped threads in the head for the stud, still had to use High Temp Lock-Tight on the threads because it unscrewed when the motor ran.
It?s now running, compression is low & leak down test on that cylinder is NG. Probably needs at least a valve job. Hope the piston & cylinder walls are ok.
Any thoughts on what I could have done to prevent this mess? The motor was completely overhauled last October. It?s still under Warranty. Guess I?ll find out how good the Jasper Warranty is.
I?ll update later.

 

[alldodge]

Re: Rocker Arm Stud pulled out

Sorry to hear you did anything to the motor. I'm figuring that since it is under warrenty and you messed with it they may be able to get out of fixing it. I think your going to have an issue with Jasper

 

[John3]

Re: Rocker Arm Stud pulled out

Sorry to hear you did anything to the motor. I'm figuring that since it is under warrenty and you messed with it they may be able to get out of fixing it. I think your going to have an issue with Jasper

Very helpful thank you.
My actual question is: What causes a newly rebuilt motor to have a stuck valve?
Any thoughts, I'd like not have it happen again.

 

[alldodge]

Re: Rocker Arm Stud pulled out

One of the # 6 Valves was stuck closed & the Rocker Arm Stud which was press fit in at the factory, had pulled out.

My actual question is: What causes a newly rebuilt motor to have a stuck valve?
Any thoughts, I'd like not have it happen again.

The valve stuck because the #6 valve stud pulled out of the head. That being said, I would say the head had probably previously over heated and Jasper didn't find the issue. Will it happen again, well this is a guessing thing, and it could happen again because it happened once before. Tapping and using red locktite if done according to manufactures recommendations should work, why it didn't I don't know. Need to have some magnafluxing (Jasper should have done this) accomplishing to see why, but that would require the engine to be disassembled.

 

[John3]

Re: Rocker Arm Stud pulled out

The valve stuck because the #6 valve stud pulled out of the head. That being said, I would say the head had probably previously over heated and Jasper didn't find the issue..............................

I hate to disagree with you but it seems more reasonable to conclude that the Stuck Valve caused the Stud to be pulled out rather than "The valve stuck because the #6 valve stud pulled out of the head." The Stud being a press fit in the head would require a fairly large external force to pull it out.
I checked with Jasper. They did a Like for Like Exchange of my Long Block. The Head is not my old Head. They've authorized my local Mechanic (I have a case number) to verify my Compression & Leak down test. I'll mention to my Mechanic your thought that the Head may have been overheated in it's past life, causing the stuck valve.

 

[alldodge]

Re: Rocker Arm Stud pulled out

Guess your right but to have a valve actually stick closed is something I've never heard of for a head with so little time. This is what makes life worth living, finding new things every day. My thought was that do to the possibility of over heating could cause the stud to become loose and pull out under load. This issue would not be so much because of a stuck valve, it would be the valve would move but the stud was pulled out because the valve spring was stronger then the resistance of the stud.

 

[John3]

Re: Rocker Arm Stud pulled out

Guess your right but to have a valve actually stick closed is something I've never heard of for a head with so little time. This is what makes life worth living, finding new things every day. My thought was that do to the possibility of over heating could cause the stud to become loose and pull out under load. This issue would not be so much because of a stuck valve, it would be the valve would move but the stud was pulled out because the valve spring was stronger then the resistance of the stud.

Thank you for your help. The Valve was definitely "Stuck Closed". When I removed the Rocker arm (The stud was still partially in the head) the self locking nut came off & I removed the Arm, Valve spring etc. You could see that the stud had partially pulled out, I'd say about 3/8inch or so (S/B the amount of Rocker Arm Motion/Cam Lift). I jury rigged a puller using a socket slipped over the stud, then a washer and the nut which I tightened to finish pulling it out.
You could see the surface was a slightly different color where the stud had been pressed in. No rust or anything though. That's why I said if I had used Lock-Tight on it at that point it might have saved a threading operation. It was a bit of a job hand tapping the threads into the head, I lubed it liberally with thread cutting oil & then had to be sure all the threads were spotlessly clean, I used Acetone, before I Lock Tighted the new stud in place. Anyway it now seems to be holding although your comment about previous overheating possibly causing the problem still worries me.

 

[Bondo]

Re: Rocker Arm Stud pulled out

Guess your right but to have a valve actually stick closed is something I've never heard of for a head with so little time. This is what makes life worth living, finding new things every day. My thought was that do to the possibility of over heating could cause the stud to become loose and pull out under load. This issue would not be so much because of a stuck valve, it would be the valve would move but the stud was pulled out because the valve spring was stronger then the resistance of the stud.

Ayuh,... An Exhaust riser water leak will do that,.....

John,.... Any Rust tracks in the manifold exhaust passages,..??

 

[John3]

Re: Rocker Arm Stud pulled out

Ayuh,... An Exhaust riser water leak will do that,.....

John,.... Any Rust tracks in the manifold exhaust passages,..??

So far I haven't removed the Aluminum Intake/Exhaust Manifold. The hole for the Rocker Arm Stud, which is now threaded, goes through the wall of the head to the inside of the head's cooling water passage. I stuck a magnet inside the threaded hole after I finished tapping it, to remove metal filings. Didn't see any signs of rust on the filings. Hope that High Temp Lock-Tight is a good thread sealer.
Guess I'll mention the possibility of an exhaust riser leak to the Mechanic on Wednesday too.
Thank You.