TURBO-DIESEL-FREAK wrote:
Clearly, YOU are not understanding that if indeed head warpage is to blame for exhaust valves breaking, then it does not matter how good the exhaust valves are... they will eventually break if not properly aligned on the exhaust valve seats. This would mean by default that an upgrade exhaust valve is NOT a 100% preventative measure!Do some research on your own without the influence of geordi! He is a guy who has stated that exhaust valves start to become weak and plastic at just above 1200 degrees Fahrenheit, (seriously, exhaust valve steel can take twice that temperature before melting and can withstand temperatures of 1700 degrees Fahrenheit all day). Do you REALLY want to trust that guy's judgement, especially after he continues to promote garbage theories like those he has on about the CRD engine thermostat?
http://www.sbintl.com/tech_library/arti ... onment.pdf I am quite sure that if you actually did some independent homework on your own rather than rely on the narrative geordi supplies here and on Facebook, you will find that a major cause of exhaust valve breakage in any engine is the cylinder head warping. When you factor in the fact that a diesel engine with an aluminum head is one of the most susceptible types of engines that have cylinder head issues and the likely conclusion becomes quite clear.
You KNOW the CRD engine has a problem with cylinder head integrity... blown gaskets have been an issue for this engine for years and guys like geordi have made serious money running around the country repairing and "upgrading" these engines. Why are you having a problem believing that if a cylinder head warps and causes a head gasket failure that it has nothing to do with the exhaust valve failures? Put 2 and 2 together man! The very place where warpage is going to be the greatest is right around those exhaust ports because of the extreme temperatures they have to endure.
Don't you think that it is at least possible that the valve seats can become misaligned due to warpage and cause the valve to strike one side more than the other, creating side loading and eventually breakage?
Again, you are beating a dead horse! I clearly and fully understand the issue and don't need to do any homework!
I have over 50 years of mechanical experience to draw my conclusions from which include working in a speed shop and automotive machine shop where I rebuilt hundreds of engines and heads. And neither geordi or anyone else has any influence on my thoughts and posts, they are my own and I stand by them!
It makes absolutely
NO difference what the cause of a failed valve in this engine, which you nor I or anyone else knows the exact ROOT CAUSE at this point, but the catastrophic damaging outcome of a failed valve is crystal clear!
And we know most reported failures have occurred close to the 200k mileage regardless of age (years) and replacing exhaust valves before this 200k mark is the ONLY option we know for a fact that can help prevent an occurrence. No one to date to my knowledge has ever reported suffering a broken valve soon AFTER replacing their exhaust valves with new ones in the short term.
So one must beg the question, IF valve breakage is due to head warpage or valve seat warpage as you theorize, why do we not ever hear of valves breaking soon after replacing exhaust valves with new ones??? Did new valves suddenly cure a warped head or valve seat, which we all know is not possible. Got to be something else at play here.
While head warpage or valve seat issues may be a contributing factor, we simply
DON'T KNOW for sure what the root cause at this point in time. It has never been established!
As I have stated before, I personally think exposure to high heat over time along with stem metal exfoliation due to soot particle blasting by the EGR all contribute to metal fatigue and are the chief contributors to the cause of exhaust valve failure and the Metallurgy Test Report that was performed on failed valves that was published on this forum backs up this in my opinion. And there is also the possibility of a bad batch of valves that was used by the manufacturer that was discussed which would explain why some engines go well beyond the 200k mark and never suffer a valve failure.
Theorize all you want, just keep the discussions civil.
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Supporting Vendor and Moderator of LOST05 Jeep Liberty CRD Limited
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