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Yes...another year eh :^) Here we are...a really great pic you took there and speaks volumes about what we enjoy :^)Another year right?
I do not have the the definitive answer of a cause, although alot of the physical evidence I have discovered (and not youtube videos) shows issues with both the cam surface, the lifter bearings, and possible valve control.
Reason why I argue with the following:
It's Idle Time
It's the cam so high in the block and not getting crank splash lubrication
It's no flow oil to the lifters
It's not enough oil flow to the lifters
And whatever else clickbait videos come of it, is that they all do not agree with the physical, and statistical data on the failures. They all have had lime light on revenue youtube and none of them are going to save an engine with bad parts. At best, I call these the Hemi Tick Fads. They generate intrest, and money.
Just like the newest idea of hellcat oil pump everything. It's not the fix, cause it does not meet the data as a fix.
It's just a hopeful idea, just like those who:
Raised the Idle RPM
Installed higher pressure / volume pumps
Installed aftermarket lifters
For majority, lifter failure required 70-110K miles to become an issue. And most of those who did the repair typcially do not keep the car that long or it gets totaled from other stuff before the issue may happen again.
And when you have same engine, having same issues several times with short period perhaps that is a specfic failure on that engine, or maintence of it and not a leading front man for a whole slew of failures than in grand scheme are low compared to non-issue hemis.
And when you claim to be the master idea man behind a photo, of lifters, claiming one of them has your parts in it. When in fact it is far from the truth any amount of respect I may have had is def gone.
I had the failure, and very much was upset. I had went on a limb, bought a car never thought I could and it broke on me. However, 70,000 miles after my repair I went for a drive this foggy morning as tradition as got photos. (always seems foggy around Xmas and NY)
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I've surmised this notion in previous threads; there are 144 needle bearings installed in most engines across many years. That is bucket loads (get the joke :^) of needle bearings - times however many engines are on the road over many years.
My take on lifter failure root cause are the needle bearings themselves. Their integrity - which means that every single last one of them - have been produced to fully meet the Engineering Specifications and Manufacturing Standards - is critical.
We'll never know whether a contract supplier used a batch of poor / improper blend of high chromium steel to produce them - or did not properly harden them - where all the suspect units were then mixed with good units that were then forwarded to another contractor for assembly. These are just two variables that can really create problems over many platforms and over many years. Then there are some needle bearings that indeed would have internal flaws at the molecular level - so again its just a matter of time before that single unit is compromised while under load and results a cascading failure event.
Given the critical nature of similar componentry used throughout the aerospace industry - given what's on the line - they are literally inspected down to the molecular level to weed them out. This is not done with GEN III lifter needle bearings and if it is - its on a (large) batch basis of a set percentage sampling process.
All the great advantages of a roller cam / lifter system are well-known - no point going into. I do not believe lobe integrity or lifter roller (materials) integrity are factors here. The actual dynamic loading - even at high rpm is a relative cakewalk at the lobe / roller interfaces. At low rpm there may indeed be loading that is actually more stressful. A good analogy here would be coil packs that, while at idle, are experiencing more electrical stress (excessive dwell --> heat buildup) than at higher rpm.
Lack of lubrication is a worthy root-cause scenario - given the number of police vehicle failures versus everything else.
One thing for-sure is the ongoing and 100% ridiculous(!) notion that oil viscosity has any role whatsoever. I marvel at those on other forums who have gone down a baseless and dumbass rabbit hole that somehow oil viscosity is a mitigating factor that is contributing to a / any lifter failure mode. Pure / unadulterated stupidity and unfortunately the BULLSH!T that sucks good folks into levels of anxiety that then forces(!) them into buying specific brands of oil, using viscosities that do not meet the OEM recommendations, adding f'n oil additives (what a total hoodwink across the industry - oil additives) and adhering to service intervals that meet some sort of emotional level of well-being. Truly disgusting and 100% based on anecdotal BS.
FYI; oil viscosity dictates the rate that oil moves across bearing interfaces in order to meet projected film strength and remove(!) thermal energy as a direct result of the load per unit area and time - at a specific clearance. This is not rocket science and is well-understood by the Engineers who designed those clearances in the first place.
Happy New Year folks...