busted rocker stud?

[grumpyvette]

 

the rocker stud failure could be the result of many things

but lack of oil flow, that allows the rocker ball to pressure weld to the rocker and snap off the stud is certainly a comon one, it could certainly be a defective stud,and that appears to be the case here as theres no indication of extra heat and the break appears to be a stress crack, or its very unlikely but, too much spring pressure,could contribute to the failure.

in some cases the pushrod was clogged, the hole in the pushrod didn,t align with the hole in the rocker or the lifter was defective and was not pumping oil, but in some cases its not paying attention when the valves are adjusted, and getting the rocker adjustment nut, too tight, because that limits the oil flow rates , up the pushrod, and the lifter preload is pushed too far, or clearance issues are certainly suspect

 

 

from the arp web site

 

Recognizing Common Failures

 

There are six types of metallurgical failures that affect fasteners. Each type has unique identifying physical characteristics. The following examples are designed to be used like a spark plug reading chart to help analyze fastener failures.

 

While few of us have access to sophisticated analysis equipment, a standard Bausch and Lomb three lens magnifying glass will generally show 98% of what we want to see. Several of the photos below have been taken utilizing a Scanning Electron Microscope (SEM) and are presented to simply illustrate typical grain configurations after failure.

 

 

 

. Cyclic fatigue failure originated by

hydrogen embrittlement.

 

Some of the high strength “quench and temper†steel alloys used in fastener manufacture are subject to “hydrogen embrittlement.†L-19, H-11, 300M, Aeromet 100 and other similar alloys popular in drag racing, are particularly susceptible and extreme care must be exercised in manufacture. The spot on the first photo is typical of the origin of this type of failure. The second is a SEM photo at 30X magnification.

 

more info

 

http://www.arp-bolts.com/Tech/TechWhy.html

 

 

5. Cyclic fatigue cracks propagated

from a rust pit (stress corrosion)

 

Again, many of the high strength steel alloys are susceptible to stress corrosion. The photos illustrate such a failure. The first picture is a digital photo with an arrow pointing to the double origin of the fatigue cracks. The second photograph at 30X magnification shows a third arrow pointing to the juncture of the cracks propagating from the rust pits. L-19, H-11, 300M and Aeromet 100, are particularly susceptible to stress corrosion and must be kept well oiled and never exposed to moisture including sweat. Inconel 718, ARP 3.5 and Custom age 625+ are immune to both hydrogen embrittlement and stress corrosion.