Ram Hemi hydraulic lifter failure...oil related?

[JosephA]

Here is an SRT that suffered the same lifter failure as my MDS lifters did, but his rotated 90 degrees; a lot more than mine.

Quote
Wondering how common this is, or if any of you have experienced it. Recently, I had one of the lifters fail in my 2014 SRT, it had ~ 50k miles on it at the time of failure. The failure of the lifter (which rotated 90 degrees) caused the cam lobe to wear out.

The repair ended up costing a little over $7000CAD (~5600USD). Unfortunately in Canada, us SRT owners get stuck with a 36k/3 year warranty, so I was out of luck with that, and Chrysler did not offer to help (although they did say I could go to the dealer for a free re-fix of my brake booster fix -- thanks).

Quite concerning is the fact that I am apprehensive that it may happen again because I don't truly know what the root cause was, and/or how common it is.

Attaching pictures of the camshaft & failed lifter.


And here another guy explains how the lifters are failing and rotating off center:

Quote
Because the lifter retainer is plastic it can break or spread apart and allow the lifter to rotate which it is not designed to do. other designs connect both lifters together with a tie bar or other designs. Also if the retainer screws loosen the lifter will fall out and again same problem.


Source: https://jeepgarage.org/f97/2014-srt-lifter-failure-causing-cam-failure-7k-repair-187554.html

I am pretty sure it is becoming quite clear that any form of displacement on demand system is doomed to failure. While some might reach 150,000 miles, thousands of others are failing prematurely. I supposed this all hinges on oil-change frequencies, quality of oil used, driving habits, regional climate, etc. But no matter the causes, there is no doubt that any DOD (or MDS) is doomed to fail at one point or another.

Are the MDS (OR AFM) savings (if any) worth the cost of maintenance and/or repairs? At $7,000 dollars give or take, I'd say the answer is an astounding NO!

Joe

 

[PimTac]

There was a point made on another hemi tick thread here that no oil will fix a engineering fault. I believe that. A thick oil or a oil with tons of moly will only mask the problem or delay the inevitable failure.

Whether the failure rate is 2% or 20%, it comes across to me that consumers who buy these hemi engined vehicles are playing a lottery of sorts. Most may not even know the issue exists.

 

[dave1251]

Originally Posted by PimTac
There was a point made on another hemi tick thread here that no oil will fix a engineering fault. I believe that. A thick oil or a oil with tons of moly will only mask the problem or delay the inevitable failure.

Whether the failure rate is 2% or 20%, it comes across to me that consumers who buy these hemi engined vehicles are playing a lottery of sorts. Most may not even know the issue exists.




The HEMI and GM V8's are actually failing at lower rate then the industry average. So everyone is playing the lottery.

 

[PimTac]

Originally Posted by dave1251
Originally Posted by PimTac
There was a point made on another hemi tick thread here that no oil will fix a engineering fault. I believe that. A thick oil or a oil with tons of moly will only mask the problem or delay the inevitable failure.

Whether the failure rate is 2% or 20%, it comes across to me that consumers who buy these hemi engined vehicles are playing a lottery of sorts. Most may not even know the issue exists.




The HEMI and GM V8's are actually failing at lower rate then the industry average. So everyone is playing the lottery.



In some ways yes. Changes in engines and cars in general are happening quickly. There is a mantra here that buyers should wait a couple or so years for the bugs to get worked out. Unfortunately the changes are happening faster than that.

 

[dave1251]

The HEMI has been in production for close to 17 years.

 

[OVERKILL]

Originally Posted by JosephA
Here is an SRT that suffered the same lifter failure as my MDS lifters did, but his rotated 90 degrees; a lot more than mine.

Quote
Wondering how common this is, or if any of you have experienced it. Recently, I had one of the lifters fail in my 2014 SRT, it had ~ 50k miles on it at the time of failure. The failure of the lifter (which rotated 90 degrees) caused the cam lobe to wear out.

The repair ended up costing a little over $7000CAD (~5600USD). Unfortunately in Canada, us SRT owners get stuck with a 36k/3 year warranty, so I was out of luck with that, and Chrysler did not offer to help (although they did say I could go to the dealer for a free re-fix of my brake booster fix -- thanks).

Quite concerning is the fact that I am apprehensive that it may happen again because I don't truly know what the root cause was, and/or how common it is.

Attaching pictures of the camshaft & failed lifter.


And here another guy explains how the lifters are failing and rotating off center:

Quote
Because the lifter retainer is plastic it can break or spread apart and allow the lifter to rotate which it is not designed to do. other designs connect both lifters together with a tie bar or other designs. Also if the retainer screws loosen the lifter will fall out and again same problem.


Source: https://jeepgarage.org/f97/2014-srt-lifter-failure-causing-cam-failure-7k-repair-187554.html

I am pretty sure it is becoming quite clear that any form of displacement on demand system is doomed to failure. While some might reach 150,000 miles, thousands of others are failing prematurely. I supposed this all hinges on oil-change frequencies, quality of oil used, driving habits, regional climate, etc. But no matter the causes, there is no doubt that any DOD (or MDS) is doomed to fail at one point or another.

Are the MDS (OR AFM) savings (if any) worth the cost of maintenance and/or repairs? At $7,000 dollars give or take, I'd say the answer is an astounding NO!

Joe


That's exactly what I was pointing to earlier. The plastic guide that sits on top of the lifters and keep them straight can likely quite readily warp, deform or fail, allowing the lifters to either rock around or rotate, which he experienced. That has nothing (or very little) to do with MDS, but it could DEFINITELY lead to lifter failure, and thus wiping out a lobe, as soon as a unit starting rolling off centre.

BTW, once that starts happening, it doesn't take much rotation for the roller to either stop rolling, or "scrubbing" the lobe, which will rapidly wear the roller as well as the lobe, resulting in seizure and what we've seen when they let go.

 

[PimTac]

Originally Posted by dave1251
The HEMI has been in production for close to 17 years.



Perhaps. I don't know when the MDS system was added to these engines but it seems Fiat has had plenty of time to figure it out.

 

[OVERKILL]

Originally Posted by JosephA
Okay on the plastic keepers on top of the lifters. I noted that too when I removed my lifters, and I was stunned after seeing plastic keepers holding the lifters in place. Chrysler made a huge mistake with that.


Yes, that's what I was trying to get you to see. You appeared to be confusing that unit with something you thought was internal to the lifter body, but it's not. What keeps the lifters straight are four of these units.

Originally Posted by JosephA
Now about the liters, it is very clear to me how the MDS lifters work. The lower half of the lifter is what bobs up and down when the pin is unlocked. The lower end of the lifter is held in place by a flat piston of some kind. But from the inward side, you can see how the lower half of the lifter slides into its own body, while the mid section to the top of the lifters is sustained in a frozen no moving position. Logically, if the lower end of the lifter is able to move up and down, this means something internal has to keep its proper vertical orientation. That "something" might be failing, which would also explain why the lock pin is off center. Keep in mind that the lock pin is what allows the lifter to collapse or expand.


You may want to re-evaluate that. As visible in the pictures, there is essentially a piston inside the UPPER portion of the lifter body that's retained by the pin and once released, is allowed to slide up and down inside the bore of the lifter body, supported by the spring below it. Inside the upper portion of the piston is the small spring and cylinder assembly that gets filled with oil that one would see in a conventional lifter. It being a piston is what keeps it in proper vertical orientation, as I have noted a few times, this is all readily visible in the cutaway diagrams I've provided, but for the sake of convenience, here it is again:

The entire lifter body follows the profile of the cam as it normally would, moving up and down in the usual fashion, the difference in operation comes from the inner section of the lifter body sliding up and down inside the lifter, simply keeping pressure on the pushrod, but not actuating the valve.

Originally Posted by JosephA
As with GM displacement on demand systems, oil pressure is used to push in the lock pin and allow the lifter to collapse in on itself. Likewise, oil pressure is used to expand the lifter until it reaches maximum extension and the locking pin is flushed in place of its hole, and oil pressure returns to normal lubrication.


No, oil pressure is used to press in the spring-loaded pin, which engages the MDS. This is achieved by the activation of the MDS solenoids which supply oil to the passages that interface with the pin section of the lifter body. When the solenoid closes and that oil pressure is removed, the spring inside the unit pushes the pin back into the locked position, disabling the MDS function. There is only oil pressure at that orifice when MDS is engaged. This is readily visible in the video you linked earlier actually, and the spring is visible in the picture above.

Originally Posted by JosephA
Think really clear here. If the hole remains open during lifter expansion and operation, what do you believe will result from that?


I have no problem thinking clearly, just an FYI

The oil has nowhere to go, barring bore-to-body leakage, which is inevitable and would happen regardless, except into the body of the lifter, which is fixed volume as again, visible in the cutaway pictures, which clearly show the pin section. And keep in mind, this is only under pressure when the solenoid to engage MDS is active. So you'd end up with an oil covered/dripping lifter, which you'd end up with anyways when the pin is properly located in the bore, except that with the pin out of alignment, MDS may not properly engage and the valve would get opened, despite the call for MDS operation by the PCM.

Originally Posted by JosephA
Logically, soundly, and mechanically, oil volume and pressure will be lost It's really not that difficult. Run 4 smaller water hoses from a single larger hose, the 4 smaller water hoses will output and carry the same volume of water, as long as they all share the same level of flow-resistance. Now pop one of the 4 water hoses, and the volume for the leaking hose will increase, while the volume in the other 3 water hoses will be decreased. This is exactly what is going on with the failed MDS lifters. Therefore, logically, and without any trace of doubt, this would mean a reduction of oil volume to the other lifters on the same valve train. And since #8 is all the way in the back, this explains why #8 doesn't seem to get enough oil; not just with my engine, but others as well that have suffered #8 intake lifter failure.


Where do you think this oil is going? The pin isn't a dead-end pressure point that, if displaced, results in your firehose analogy. It's a reasonably generous interface with a small spring behind it that, when exposed to oil pressure, is pushed back, along with some oil, into the body of the lifter, which is of fixed capacity. The hose analogy falls short because that entire passage is already going to have oil in it and the volume is not vast. When the solenoid opens, pressurizing that chamber to displace that pin, the actual volume of oil required is quite small. Yes, there will be some leakage around the body of the lifter, as already covered, but the lifter body is already oiled in that manner via the conventional oil passages so the overall volume lost here should not be of consequence.

If #8 is receiving inadequate oil, than that's likely an oiling design system issue and not tied into this issue. Which again makes sense once you consider that non-MDS engines have experienced the same failure.

Originally Posted by JosephA
There's a reason why my career as an excellent F-16 Fighter Jet mechanic came with many awards. My troubleshooting skills are quite excellent..not to pat myself on the back. LOL But the Air Force inspires us to use our minds, schematics, flowcharts, and much more to understand why failures happens. But so far, only one person on here has offered a viable reason for the lifter failures. But there hasn't been any logical evidence to back up his theory. While I may not have laboratory evidence, seems quite logical to me based on science alone (physics 101).

Joe


I've offered an absolute TON of logical evidence here, so please don't pat yourself on the back too hard. I also have a great deal of troubleshooting experience, that, while not related to my automotive hobby, has served me well in it.

 

[Skippy722]

Originally Posted by PimTac
Originally Posted by dave1251
The HEMI has been in production for close to 17 years.



Perhaps. I don't know when the MDS system was added to these engines but it seems Fiat has had plenty of time to figure it out.



Debuted in 2004 for only cars at first, trucks and SUV's got it in 2006. The 5.7 got a relatively big upgrade in 2009 to the "Eagle" hemi, and it seems those are worse than the pre 2009 models, I have no real data to back that up though.

 

[tiger862]

My experience with roller lifter is they don't like higher rpms. On higher rpm with no matter what oil if spring rate in lifters weakens over time you get lifter floating. With this condition lifters lift off cam then back down causing wearing of rollers then breaking of needles causing complete failure. When GM first used rollers in a small block Camaro I can't tell you how many engines we sent back to GM for inspection. No MDS with plastic holders. Rollers and cam replacement under warranty (36k) but some customers put older cam and lifter to fix permanently. Now we complain about replacement parts at 60k up but if you remember older cars in 40s all the through 60s were lucky to last 80k without rebuild. Look at Comp Cam roller failure for older cars. Search and enjoy. Not all MDS causes this.

 

[dave1251]

Originally Posted by PimTac
Originally Posted by dave1251
The HEMI has been in production for close to 17 years.



Perhaps. I don't know when the MDS system was added to these engines but it seems Fiat has had plenty of time to figure it out.




14 years ago and the failure isn't limited to MDS HEMI's and the rate of failure isn't any higher then other production engines.

 

[SteveSRT8]

Originally Posted by OVERKILL


Originally Posted by JosephA
There's a reason why my career as an excellent F-16 Fighter Jet mechanic came with many awards. My troubleshooting skills are quite excellent..not to pat myself on the back.



I've offered an absolute TON of logical evidence here, so please don't pat yourself on the back too hard. I also have a great deal of troubleshooting experience, that, while not related to my automotive hobby, has served me well in it.



As the regulars here know you are quite logical and well researched. And we all know you don't have to be a jet mechanic to have the ability to deduce the causes of failures.


As stated earlier, the new gen Hemi has been extremely reliable overall and the Internet simply amplifies the failures by repetition. Also, there are not very many 6.1's out there but even they had a wrist pin issue in a few that was a catastrophic failure. But you likely didn't hear about that unless you were on the Net on one of the many SRT8 boards that formed long ago. My heart always goes out to the folks who have problems like this that ruin what most think is a good car/truck.


IMO anyone who makes millions of engines will have some failures.

 

[JosephA]

Originally Posted by dave1251
Originally Posted by JosephA
Quote
Indeed and there has been how many million Hemi engines produced? It's very rare and it's not limited to MDS. Now this isn't comforting to ones who own a granaded engine but it's rare and in mass production it's a risk at same time it's a small risk.


I strongly disagree sir. This is by no means a "rare problem". Far from it. My friends Dodge Ram 2011 Hemi is doing this, and I will be repairing his after my wifes truck. I've spoken to the local mechanic in my town and he does 1 to 2 of these per week; some from warranty repair, others out of pocket. There are also dozens and dozens of YouTube video's of other Hemi owners suffering the same problem, with some less than 40,000 miles. Not to mention to thousands of complaints I've read from different complaint sites, mostly reporting on hemi lifter failure and camshaft damage.

You should be willing to admit that any type of lifter failure at such low mileage is bad....bad....bad. Because these kinds of failures are unheard of. So can you justify a $36,000 dollar truck with the potentiality of a $7,000 dollar repair with less than $100,000 miles, give or take? And to brush it off as "non-comforting" to the unlucky ones, as though it doesn't matter, is preposterous to say the least. If the problem is so rare as you suggest, then why is Chrysler so unwilling to help with the problem? Tell you another story. The warranty department refused to repair our truck when it was under warranty, and instead told the dealership that they were responsible for the repair since they were servicing our truck with the wrong oil....being 5W-30 non-synthetic. The dealership turned around and lied, claiming it merely needed a $988 dollar tuneup. That's right...a tuneup. Somehow they were able to baby the problem and get it to exceed the warranty, and that's when the problem not only came back, but grew much worse. I suspect the dealership merely replaced the bad lifter that knocked before, and that bought them another 4,000 miles at which time the warranty expired.

No sir, this is not rare at all. Hundreds, if not thousands of people are repairing their dodge vehicles, and dumping them, trying to get back any amount of dollar they've wasted on such poor quality vehicles.

All of my years as a mechanic, and not once have I've seen a GM motor with destroyed lifters; neither a Toyota, nor even a Ford, and all with less than 100K miles.

As for the non-hemi failures, I have not seen any so far. And if this is the case (which my evidence does not agree with your supposition), then there is definitely a design flaw if lifters can be destroyed even without MDS.

Besides, I know your statement is not only illogical, but irrational as well. Why? Because GM is currently having the exact same problems on their Z71's with the AFM (same as MDS) trucks. Lifter failures and camshaft destruction.

Coincidence? Or the same level of "bad luck" to the rare victims of these atrocities?

Besides, since the problem is supposedly so rare, then heck, Chrysler shouldn't have a single problem paying to help out these rare victims. But nope...it's on the consumer....thousands of them. And there should be ZERO lifter failures and ZERO camshaft destruction, short of outright neglect.

Joe



Sorry the math does not bare in your favor it's a rare problem it's really in the very low single digits under 2% in total failures in the equivalent of 100K miles of useage you can disagree but the numbers don't favor your position. GM does not have widespread failures either. Individuals like yourself fall into the trap because you can find 2 dozen or so fellow owners with a similar situation out of millions there is a widespread problem. Sorry Bud it's just not the case and it's a shame you are unable to see the big picture even presented with facts such as the same failure predates your theory you can not accept this.


You are using fuzzy math to hide the issue. If there are 650,000 Hemi's sold, and you claim ONLY a 2% percent error rate, that's 13,000 ticked off customers who got screwed. And how do you even know what the exact failure rate is? Are you basing this on estimation, or fact? How many broken down hemi's were sent to the dealership for repair? How many go unreported? Do you even know? Or do you even care? Based on your illogical presumptions that don't explain a back logged status of lifters, some 2 to 3 months waiting time, destroys your supposition all together.

I'm beginning to wonder if you are just a corporate (or paid) troll to spread disinformation on the web to help protect Chrysler (or should we call it Fiat).

Prior to the introduction of both the MDS and the DOD, were their lifter and camshaft failures? Nope. Are we seeing lifter and camshaft failures happening since the MDS and DOD? Yep. Logic concludes then that THERE is the problem.

The big picture is this. People are getting screwed after purchasing a very expensive product that has cost them time, frustration, and money. This is why it is better to buy a truck from a company that cares about their customers, and does all that it can to correct any defects to help protect their image. Toyota has the best customer service I have ever seen. One of my best friends worked in Atlanta GA and he told me how they would replace worn out engines at company expense if there was even the slightest hint of burning oil, and that despite obvious customer neglect. Yet Chrysler, AND GM (possibly Ford) will ignore obvious defects and blames their defective products on customers.

My own neighbor (who works as a Chrysler Tech) read your post....and well, I can't repeat what he just said, but he's reading your post as I type this. LOL Of course, to protect him and his job, I cannot give out his name.

He and his workmates are repairing roughly 2 to 3 of these per week. He is helping me with mine, but I've done most of the work; he is basically here for moral support. But right now, I'm stuck on hold as I have to wait for those pesky Hellcat lifters which are back-ordered to fix all of us "rare" engine failure victims.

You still haven't explained that.....If this is rare and such a small percentage, then why is there a long back order on lifters, both stock and hellcat lifters?

Joe

 

[JosephA]

Originally Posted by PimTac
There was a point made on another hemi tick thread here that no oil will fix a engineering fault. I believe that. A thick oil or a oil with tons of moly will only mask the problem or delay the inevitable failure.

Whether the failure rate is 2% or 20%, it comes across to me that consumers who buy these hemi engined vehicles are playing a lottery of sorts. Most may not even know the issue exists.



Amen to that my friend. The Chrysler defenders are ignoring the failures and acting as though all is well, and there's nothing to worry about. Just spend $37,000 bucks or more, and we will sell you a fine looking truck. Oh but wait, you might actually get the bullet in the 5th chamber and it will destroy you. But hey, it's a 1 in 6 chance, so all will be just dandy. Happy Hemi'ing....if/when you can.

Joe

 

[JosephA]

Originally Posted by OVERKILL
Originally Posted by JosephA
Okay on the plastic keepers on top of the lifters. I noted that too when I removed my lifters, and I was stunned after seeing plastic keepers holding the lifters in place. Chrysler made a huge mistake with that.


Yes, that's what I was trying to get you to see. You appeared to be confusing that unit with something you thought was internal to the lifter body, but it's not. What keeps the lifters straight are four of these units.

Originally Posted by JosephA
Now about the liters, it is very clear to me how the MDS lifters work. The lower half of the lifter is what bobs up and down when the pin is unlocked. The lower end of the lifter is held in place by a flat piston of some kind. But from the inward side, you can see how the lower half of the lifter slides into its own body, while the mid section to the top of the lifters is sustained in a frozen no moving position. Logically, if the lower end of the lifter is able to move up and down, this means something internal has to keep its proper vertical orientation. That "something" might be failing, which would also explain why the lock pin is off center. Keep in mind that the lock pin is what allows the lifter to collapse or expand.


You may want to re-evaluate that. As visible in the pictures, there is essentially a piston inside the UPPER portion of the lifter body that's retained by the pin and once released, is allowed to slide up and down inside the bore of the lifter body, supported by the spring below it. Inside the upper portion of the piston is the small spring and cylinder assembly that gets filled with oil that one would see in a conventional lifter. It being a piston is what keeps it in proper vertical orientation, as I have noted a few times, this is all readily visible in the cutaway diagrams I've provided, but for the sake of convenience, here it is again:

The entire lifter body follows the profile of the cam as it normally would, moving up and down in the usual fashion, the difference in operation comes from the inner section of the lifter body sliding up and down inside the lifter, simply keeping pressure on the pushrod, but not actuating the valve.

Originally Posted by JosephA
As with GM displacement on demand systems, oil pressure is used to push in the lock pin and allow the lifter to collapse in on itself. Likewise, oil pressure is used to expand the lifter until it reaches maximum extension and the locking pin is flushed in place of its hole, and oil pressure returns to normal lubrication.


No, oil pressure is used to press in the spring-loaded pin, which engages the MDS. This is achieved by the activation of the MDS solenoids which supply oil to the passages that interface with the pin section of the lifter body. When the solenoid closes and that oil pressure is removed, the spring inside the unit pushes the pin back into the locked position, disabling the MDS function. There is only oil pressure at that orifice when MDS is engaged. This is readily visible in the video you linked earlier actually, and the spring is visible in the picture above.

Originally Posted by JosephA
Think really clear here. If the hole remains open during lifter expansion and operation, what do you believe will result from that?


I have no problem thinking clearly, just an FYI

The oil has nowhere to go, barring bore-to-body leakage, which is inevitable and would happen regardless, except into the body of the lifter, which is fixed volume as again, visible in the cutaway pictures, which clearly show the pin section. And keep in mind, this is only under pressure when the solenoid to engage MDS is active. So you'd end up with an oil covered/dripping lifter, which you'd end up with anyways when the pin is properly located in the bore, except that with the pin out of alignment, MDS may not properly engage and the valve would get opened, despite the call for MDS operation by the PCM.

Originally Posted by JosephA
Logically, soundly, and mechanically, oil volume and pressure will be lost It's really not that difficult. Run 4 smaller water hoses from a single larger hose, the 4 smaller water hoses will output and carry the same volume of water, as long as they all share the same level of flow-resistance. Now pop one of the 4 water hoses, and the volume for the leaking hose will increase, while the volume in the other 3 water hoses will be decreased. This is exactly what is going on with the failed MDS lifters. Therefore, logically, and without any trace of doubt, this would mean a reduction of oil volume to the other lifters on the same valve train. And since #8 is all the way in the back, this explains why #8 doesn't seem to get enough oil; not just with my engine, but others as well that have suffered #8 intake lifter failure.


Where do you think this oil is going? The pin isn't a dead-end pressure point that, if displaced, results in your firehose analogy. It's a reasonably generous interface with a small spring behind it that, when exposed to oil pressure, is pushed back, along with some oil, into the body of the lifter, which is of fixed capacity. The hose analogy falls short because that entire passage is already going to have oil in it and the volume is not vast. When the solenoid opens, pressurizing that chamber to displace that pin, the actual volume of oil required is quite small. Yes, there will be some leakage around the body of the lifter, as already covered, but the lifter body is already oiled in that manner via the conventional oil passages so the overall volume lost here should not be of consequence.

If #8 is receiving inadequate oil, than that's likely an oiling design system issue and not tied into this issue. Which again makes sense once you consider that non-MDS engines have experienced the same failure.

Originally Posted by JosephA
There's a reason why my career as an excellent F-16 Fighter Jet mechanic came with many awards. My troubleshooting skills are quite excellent..not to pat myself on the back. LOL But the Air Force inspires us to use our minds, schematics, flowcharts, and much more to understand why failures happens. But so far, only one person on here has offered a viable reason for the lifter failures. But there hasn't been any logical evidence to back up his theory. While I may not have laboratory evidence, seems quite logical to me based on science alone (physics 101).

Joe


I've offered an absolute TON of logical evidence here, so please don't pat yourself on the back too hard. I also have a great deal of troubleshooting experience, that, while not related to my automotive hobby, has served me well in it.


As I've stated, I fully understand how the MDS lifter works. And I am correct in my explanation. Oil pressure is used to unlock the pin. But what you are missing is what happens when the oil pressure is stuck open? Does the solenoid know that? How does the computer know when to stop supplying oil pressure to the lifter despite the lock pin engaging or not? Understand?

The solenoid does not simply supply a 1 to 2 second burst of oil pressure to unlock the pin. I've already spoken to a Chrysler Tech who was trained on this engine, and it DOSE INDEED use oil pressure to help expand the lifter. The spring is there for additional force to help speed up the process, but it is also there to keep tension on the upper and lower ends of the lifter to prevent lifter floating.

The upper end of the lifter as seen in my illustration below shows the moving parts and the stationary parts. The yellow line represents the hardened stationary point. The red line shows the moving part. This clearly shows that it is possible for a lifter to rotate internally since there is really nothing there strong enough to prevent inadvertent rotation. But as you've suggested, it can rotate from the top as well since they are held in place by a plastic keeper held on by I believe a 10mm bolt. At any rate, the internals are collapsed when the lock pin is pushed inward, but the roller and body itself can rotate if the plastic keeper fails to hold the lifter in place. My buddy that works at Chrysler seems to think this is what's causing some lifters to rotate (to also include the Hellcast engine). As for the roller bearings, he believes the problem is caused by lack of lubrication mostly caused by MDS.

Now back to the oil pressure. One thing you might have overlooked is what happens when the lock pin is stuck open? I believe oil volume is lost there, and that would explain why the 2 non-MDS lifters were not as saturated as the MDS lifters. Unless you want to explain this away with another cause, perhaps a clogged oil passage or faulty solenoid, how else can you explain 2 saturated MDS lifters both with open lock pins, and 2 nearly dry lifters which are both non-MDS? The answer is quite obvious to me. Oil is being lose to the MDS lifters and starving the other 2. This again is basic physics 101. Pressure is constant throughout the system unless their is a compromise. The problem is identifying the compromise. And yet nobody on here seems to offer any suggestions of what's causing the compromise. And no, long idling is not considered a compromise; that is an operation and not a system. If an engine can suffer catastrophic failure from long idling, then we would be seeing both intake AND exhaust lifters being wiped out.

So to summarize the questions I ask of you in a friendly way:

1. How do you explain oil saturation on failed MDS lifters?
2. How do you explain low oil saturation on non-mds lifters?
3. Are the MDS oil solenoids timed with regards to pressure? Or do these solenoids react to back-pressure (as in when the MDS lifters are lock, thereby increasing oil back pressure, and thus closing off the solenoids)
4. If MDS lifters are not the problem, then why is there a huge 2 to 3 month backlog of lifter replacement?

These are very direct questions that require best guesses based on sound evaluation and examination. I look forward to your reponses.

Joe

 

[JosephA]

Originally Posted by SteveSRT8
Originally Posted by OVERKILL


Originally Posted by JosephA
There's a reason why my career as an excellent F-16 Fighter Jet mechanic came with many awards. My troubleshooting skills are quite excellent..not to pat myself on the back.



I've offered an absolute TON of logical evidence here, so please don't pat yourself on the back too hard. I also have a great deal of troubleshooting experience, that, while not related to my automotive hobby, has served me well in it.



As the regulars here know you are quite logical and well researched. And we all know you don't have to be a jet mechanic to have the ability to deduce the causes of failures.


As stated earlier, the new gen Hemi has been extremely reliable overall and the Internet simply amplifies the failures by repetition. Also, there are not very many 6.1's out there but even they had a wrist pin issue in a few that was a catastrophic failure. But you likely didn't hear about that unless you were on the Net on one of the many SRT8 boards that formed long ago. My heart always goes out to the folks who have problems like this that ruin what most think is a good car/truck.


IMO anyone who makes millions of engines will have some failures.


LOL How much are you being paid to say that?

The internet amplifies the problem eh? I suppose a Chrysler tech repairing 1 to 2 of these PER WEEK is simply amplifying the problem by repeating it. I suppose a huge 2 to 3 month wait on back-logged orders for lifters is just internet amplification?

How do you logically explain this?

Joe

 

[JosephA]

Originally Posted by tiger862
My experience with roller lifter is they don't like higher rpms. On higher rpm with no matter what oil if spring rate in lifters weakens over time you get lifter floating. With this condition lifters lift off cam then back down causing wearing of rollers then breaking of needles causing complete failure. When GM first used rollers in a small block Camaro I can't tell you how many engines we sent back to GM for inspection. No MDS with plastic holders. Rollers and cam replacement under warranty (36k) but some customers put older cam and lifter to fix permanently. Now we complain about replacement parts at 60k up but if you remember older cars in 40s all the through 60s were lucky to last 80k without rebuild. Look at Comp Cam roller failure for older cars. Search and enjoy. Not all MDS causes this.


Hmmm....I have to disagree. While my comment cannot be factually based, but as an owner of 60's vehicles (1966 Ford Mustang, a 1964 Pontiac Granprix, a 1963 Ford Fairlane), I can honestly say that my problems with those cares was rare and cheap compared to today's cars. Camshaft and lifter wear would take several hundred thousand miles, short of someone refusing to change their oil. My 302 Ford had a high lift cam with 290 duration, and man it sounded great. Raced it for nearly a year before the crank bearings finally gave out. Pulled it apart, and the cam and lifters looked great. Sure I saw minimal wearing, but nothing like I've just witnessed with the poorly designed Hemi.

I've owned classec cars, and I can tell you without any doubt that those cars were built to last, and not just for 6 years until it's paid for like modern vehicles are. Sure we had typical brake repairs, coolant problems or overheating, and water pump failures. But overall, those cars were easier to work on. [censored] my 65 Pontiac has roughly the same horse power as modern Hemi's, and yet I still averages about 16mpg on a 3 speed slim-gim transmission. And it would smoke the [censored] out of those tires. Granted I know the modern Hemi puts out a great deal of power. But what good is that power if it isn't reliable horse power?

Joe

 

[OVERKILL]

Originally Posted by JosephA

As I've stated, I fully understand how the MDS lifter works. And I am correct in my explanation.


I don't believe that's the case.

Originally Posted by JosephA
Oil pressure is used to unlock the pin.

Yes, oil pressure is used to push the pin into the body, allowing the internals to collapse. You originally claimed:

Originally Posted by JosephA
As with GM displacement on demand systems, oil pressure is used to push in the lock pin and allow the lifter to collapse in on itself. Likewise, oil pressure is used to expand the lifter until it reaches maximum extension and the locking pin is flushed in place of its hole, and oil pressure returns to normal lubrication.


That's inaccurate. Oil pressure is used to activate the collapse function. Oil pressure is removed when MDS is disabled, which results in the pin sliding back out as the lifter cycles, locking it back into place and resuming normal operation.

Originally Posted by JosephA
But what you are missing is what happens when the oil pressure is stuck open? Does the solenoid know that? How does the computer know when to stop supplying oil pressure to the lifter despite the lock pin engaging or not? Understand?

If you ask me if I "understand" one more time I'm going to lose my mind. I have been exceedingly polite in this exchange, please don't turn this nasty.

You are vastly over-complicating the function of the system. It's exceedingly simple, and no, the computer has no idea if the lifters are collapsed or not, it assumed they are when the solenoids are activated.
- Solenoid OFF, MDS OFF, the feed tubes to the lock pins is unpressurized, lifters operate normally.
- Solenoid ON, MDS ON, the feed tubes to the lock pins are pressurized, the lifters collapse.

This is readily visible in the bloody video you linked to. The solenoids stay "live" while MDS is engaged. They turn off to disengage it. There is no split solenoid scenario where the pressure is reversed to re-activate the lifters, they are reactivated via the internal spring located behind the pin, visible in the pictures. The oil pressure is used to deactivate them and keep them deactivated.

Originally Posted by JosephA
The solenoid does not simply supply a 1 to 2 second burst of oil pressure to unlock the pin. I've already spoken to a Chrysler Tech who was trained on this engine, and it DOSE INDEED use oil pressure to help expand the lifter. The spring is there for additional force to help speed up the process, but it is also there to keep tension on the upper and lower ends of the lifter to prevent lifter floating.

The solenoid stays active the entire time MDS is engaged, as I've indicated above.

Originally Posted by JosephA
The upper end of the lifter as seen in my illustration below shows the moving parts and the stationary parts. The yellow line represents the hardened stationary point. The red line shows the moving part. This clearly shows that it is possible for a lifter to rotate internally since there is really nothing there strong enough to prevent inadvertent rotation. But as you've suggested, it can rotate from the top as well since they are held in place by a plastic keeper held on by I believe a 10mm bolt. At any rate, the internals are collapsed when the lock pin is pushed inward, but the roller and body itself can rotate if the plastic keeper fails to hold the lifter in place. My buddy that works at Chrysler seems to think this is what's causing some lifters to rotate (to also include the Hellcast engine). As for the roller bearings, he believes the problem is caused by lack of lubrication mostly caused by MDS.


The yellow section is most certainly not stationary, it's the BODY of the lifter, it follows the profile of the cam lobe! It's what the roller is attached to, and the roller is constantly following the lobe profile. The part that BECOMES stationary when the pin is displaced is the UPPER portion of the lifter, which basically resembles a tall piston, and the internal spring, which you've captured in your orange line, is there to keep pressure on it so the pushrod doesn't get bumped out.

If the internal piston assembly rotates (which it appears to have in your engine) then it may prevent the pin from being displaced, thus preventing that valve from participating in MDS.

And if your buddy has confirmed that the bodies are rotating due to the plastic guide, even in the non-MDS HellCat engine, then that simply compounds my 6.1L and manual transmission non-MDS examples and again shows that the problem isn't MDS-related.

Originally Posted by JosephA
Now back to the oil pressure. One thing you might have overlooked is what happens when the lock pin is stuck open? I believe oil volume is lost there,

To where? I covered that in the post you are replying to here. The lifter isn't a black hole, it's a fixed volume assembly, and that volume is SMALL. There will be leakage around the body, but there is always leakage around the body from normal lubrication, so I can't see this having any real impact.

Originally Posted by JosephA
and that would explain why the 2 non-MDS lifters were not as saturated as the MDS lifters.

Because they don't have a hole in the side that gets filled with and hit with oil. It isn't going to take a lot of oil for them to look significantly "wetter" than the ones without the big orifice in the side of them.

Originally Posted by JosephA
Unless you want to explain this away with another cause, perhaps a clogged oil passage or faulty solenoid, how else can you explain 2 saturated MDS lifters both with open lock pins, and 2 nearly dry lifters which are both non-MDS? The answer is quite obvious to me. Oil is being lose to the MDS lifters and starving the other 2. This again is basic physics 101. Pressure is constant throughout the system unless their is a compromise. The problem is identifying the compromise.


Yes, if you got in there with a hammer drill and put a 1/2" hole in the MDS lifter gallery, you would cause a system-wide loss of oil pressure. But given that the MDS lifter hole dead-ends, that's not what is taking place here. They are wet because they have a hole in the side and it fills with oil. The non-MDS ones are not as wet because the bodies of those ones are lubed through the pressurized hole on the lifter bore, and thus there is no hole/chamber for oil to leak out of and cause them to look more "wetted".

Originally Posted by JosephA
And yet nobody on here seems to offer any suggestions of what's causing the compromise. And no, long idling is not considered a compromise; that is an operation and not a system. If an engine can suffer catastrophic failure from long idling, then we would be seeing both intake AND exhaust lifters being wiped out.

I think this part needs more research. How many folks are actually tracking whether the lifter is intake or exhaust? I'm not going to bother Googling it tonight, and I'm not going to ask my buddy at the dealer because I'm 100% sure he never checked.

Originally Posted by JosephA
So to summarize the questions I ask of you in a friendly way:

1. How do you explain oil saturation on failed MDS lifters?

Already answered that above.

Originally Posted by JosephA
2. How do you explain low oil saturation on non-mds lifters?

Already answered that above.

Originally Posted by JosephA
3. Are the MDS oil solenoids timed with regards to pressure? Or do these solenoids react to back-pressure (as in when the MDS lifters are lock, thereby increasing oil back pressure, and thus closing off the solenoids)

Neither, and this is why I don't think your statement that you understand how the system operates is correct. As I noted earlier, the system is quite simple, when the solenoids open and pressurize the feed tubes to the orifices, displacing the pins, MDS is active. When they shut off, MDS is disabled, as the pins self-seat due to their spring-loaded nature.

Originally Posted by JosephA
4. If MDS lifters are not the problem, then why is there a huge 2 to 3 month backlog of lifter replacement?

These are very direct questions that require best guesses based on sound evaluation and examination. I look forward to your reponses.

Joe


Didn't you just state to Dave:
Originally Posted by JosephA
But right now, I'm stuck on hold as I have to wait for those pesky Hellcat lifters which are back-ordered to fix all of us "rare" engine failure victims.

So why are the non-MDS HellCat lifters on back-order if the non-MDS engines are immune as per your original posit? (despite the ample evidence I've presented at this juncture with examples of the 6.1 as well as both the 5.7L and 6.4L manual transmission cars without MDS also having the problem).

Dealers aren't putting HellCat lifters into engines in for a standard lifter replacement, they are using the OE parts, which would be part numbers:
- 5038786AC
- 5038785AC

Both of which are in stock BTW.

The non-MDS lifters are part # 5038784AC (not in stock) and the HellCat ones are part # 5038787AC and also not in stock.

So, unless there is a rash of HellCat lifter failures (unlikely) I'm going to conclude that this is just a supplier shortage at this juncture. They have plenty of stock for direct replacements on their most common engines (MDS ones) and the ones on back order are for the manual-equipped cars, the 6.1L and the HellCat.

 

[tiger862]

Originally Posted by JosephA
Originally Posted by tiger862
My experience with roller lifter is they don't like higher rpms. On higher rpm with no matter what oil if spring rate in lifters weakens over time you get lifter floating. With this condition lifters lift off cam then back down causing wearing of rollers then breaking of needles causing complete failure. When GM first used rollers in a small block Camaro I can't tell you how many engines we sent back to GM for inspection. No MDS with plastic holders. Rollers and cam replacement under warranty (36k) but some customers put older cam and lifter to fix permanently. Now we complain about replacement parts at 60k up but if you remember older cars in 40s all the through 60s were lucky to last 80k without rebuild. Look at Comp Cam roller failure for older cars. Search and enjoy. Not all MDS causes this.


Hmmm....I have to disagree. While my comment cannot be factually based, but as an owner of 60's vehicles (1966 Ford Mustang, a 1964 Pontiac Granprix, a 1963 Ford Fairlane), I can honestly say that my problems with those cares was rare and cheap compared to today's cars. Camshaft and lifter wear would take several hundred thousand miles, short of someone refusing to change their oil. My 302 Ford had a high lift cam with 290 duration, and man it sounded great. Raced it for nearly a year before the crank bearings finally gave out. Pulled it apart, and the cam and lifters looked great. Sure I saw minimal wearing, but nothing like I've just witnessed with the poorly designed Hemi.

I've owned classec cars, and I can tell you without any doubt that those cars were built to last, and not just for 6 years until it's paid for like modern vehicles are. Sure we had typical brake repairs, coolant problems or overheating, and water pump failures. But overall, those cars were easier to work on. [censored] my 65 Pontiac has roughly the same horse power as modern Hemi's, and yet I still averages about 16mpg on a 3 speed slim-gim transmission. And it would smoke the [censored] out of those tires. Granted I know the modern Hemi puts out a great deal of power. But what good is that power if it isn't reliable horse power?

Joe

40 years in the business and I can guarantee you that you are comparing apples to oranges. A 4000 dollar car from 60's with inflation would be 32000 today. The warranty on these vehicles were 2 years or 24000 miles. Roller lifters are now the norm to save fuel but are a higher failure rate compared to older lifters that rode on cams. Like I said look up CompCam roller lifter failure. This is not just Dodge but all manufacturers as they love to float. Do you think taxis, police, fire etc. would be driving the vehicles that eat cams at such a high failure rate? Around here I see so many hemi vehicles with close to 200k or more. Heck I had a guy who picks up junk for a living and his Hemi has 250k without engine being opened but has put 3 transmissions in it and is a 3/4 ton pickup.

 

[OVERKILL]

Originally Posted by JosephA
Originally Posted by tiger862
My experience with roller lifter is they don't like higher rpms. On higher rpm with no matter what oil if spring rate in lifters weakens over time you get lifter floating. With this condition lifters lift off cam then back down causing wearing of rollers then breaking of needles causing complete failure. When GM first used rollers in a small block Camaro I can't tell you how many engines we sent back to GM for inspection. No MDS with plastic holders. Rollers and cam replacement under warranty (36k) but some customers put older cam and lifter to fix permanently. Now we complain about replacement parts at 60k up but if you remember older cars in 40s all the through 60s were lucky to last 80k without rebuild. Look at Comp Cam roller failure for older cars. Search and enjoy. Not all MDS causes this.


Hmmm....I have to disagree. While my comment cannot be factually based, but as an owner of 60's vehicles (1966 Ford Mustang, a 1964 Pontiac Granprix, a 1963 Ford Fairlane), I can honestly say that my problems with those cares was rare and cheap compared to today's cars. Camshaft and lifter wear would take several hundred thousand miles, short of someone refusing to change their oil. My 302 Ford had a high lift cam with 290 duration, and man it sounded great. Raced it for nearly a year before the crank bearings finally gave out. Pulled it apart, and the cam and lifters looked great. Sure I saw minimal wearing, but nothing like I've just witnessed with the poorly designed Hemi.

I've owned classec cars, and I can tell you without any doubt that those cars were built to last, and not just for 6 years until it's paid for like modern vehicles are. Sure we had typical brake repairs, coolant problems or overheating, and water pump failures. But overall, those cars were easier to work on. [censored] my 65 Pontiac has roughly the same horse power as modern Hemi's, and yet I still averages about 16mpg on a 3 speed slim-gim transmission. And it would smoke the [censored] out of those tires. Granted I know the modern Hemi puts out a great deal of power. But what good is that power if it isn't reliable horse power?

Joe


I've built several 302HO's, as I used to be big into the Mustang scene. Stock roller lifters, which mine had well over 300,000Km on them, were good for a MAXIMUM RPM ceiling of 7,000RPM and a maximum lift of ~.550 with a 1.7 ratio rocker due to the limits of the stock dog-bone and hold down setup. If you wanted to go above that, you needed aftermarket link-bar lifters. If you wanted to go well above that, you needed to switch to solid roller.

In order to retain control over the lifters at that RPM (7K) you needed heavy springs. This is due the the mass of a hydraulic roller lifter. I had a custom camshaft ground by Camshaft Innovations, and he (Jay Allen) recommended K-Motion K800 valve springs, which, at spec height, were close to 500lbs open. He was adamant that it was all about lifter control and his cams tended to work extremely well, and I don't recall anybody losing lifters when they followed his advice.

In that vein however, we did "inherit" a 302HO in an '85 GT that had a CI cam in it, but the guy had gone with aftermarket lifters. They failed. There are pictures of it on here actually. We picked up a stock low-mile shortblock, stuffed that cam in it and put in the proper Lunati link-bar lifters and it ran like a scalded ape right to the rev limiter. That engine survived two cars but eventually the Comp springs on the TFS TW's that it was wearing got some wear on them and she started into valve float at much over 6,300RPM, despite the engine wanting to go to 6,800+. My buddy sold the car, but that was a solid 300HP at the tires engine injected, more when it was topped with a Victor Jr. and a Holley HP.

The failure mode of those aftermarket lifters BTW, was nothing like we are seeing here. The pins holding the rollers in actually walked out, impacting the lifter bores. It was wild.

Here are the pics of the failed lifters:

And here is what we did with the cam that came out of that engine, note the linkbar lifters: