Ram Hemi hydraulic lifter failure...oil related?

[OVERKILL]

Originally Posted by JosephA

I could be wrong, but the 6.1 in the Challenger came with MDS, but was unavailable for the 6.4 Hemi until about 2011. So I believe the first one was an 6.1 MDS engine which became available in 2009'ish.

The Grand Cherokee I believe also came with MDS around 2005, so the second link posted might have been an MDS engine. I might have missed any comment or post from the provided links wherein they specifically mentioned if their engine was either an MDS or non-MDS engine.


Only the 5.7L during those years had MDS, the 6.1L never had it, it first appeared on SRT's with the 6.4L, but only backed by an automatic.
https://www.auto123.com/en/car-reviews/2012-chrysler-300-srt8-first-impressions/54109/

Quote
It wasn't long ago that Chrysler's 6.1L V8 HEMI engine was considered massive by modern standards; well, think again. For 2012, the SRT8 engine displaces a whopping 6.4 litres (that's 392 cubes for the retro) and belts out 470 hp matched by 470 lb-ft of torque.

Not only does the bigger HEMI create more clout, it does so more efficiently thanks to Chrysler's fuel-saving MDS cylinder deactivation technology.


Also: https://www.enginebuildermag.com/wp-content/uploads/46568ChryslerHe_00000019776.pdf

Quote
All of the 6.1L engines came without MDS so there is only one cam used for them. It has some serious lift, about 0.050 Ì‹ more than the 5.7L, so the lobes are almost as tall as the journals. Chrysler says it has 283 degrees of duration on the intake and 286 degrees on the exhaust at.006 Ì‹ and 50 degrees overlap, so it's pretty aggressive compared to the 5.7L cam.


There is also this 2010 Challenger brochure that notes that only the 5.7L, and only backed by an automatic, is available with MDS. The 6.1L does not have MDS:
https://www.dodge.com/en/pdf/2010_challenger.pdf


Originally Posted by JosephA
I can see your theory as well, and it is sound. And you might be right. But to me, if that were the case, I would have seen lifters failing on Bank 1 and not limited solely to bank 2 (again on my engine). The intake lifter for cylinder #2 was slightly wet, and had minimal chaffing. The MDS intake lifter on #4 was twisted and unlocked, with the locking pin shifted to the left side within the lifter. It was soaked heavily with engine oil. The intake lifter for #6 was also shifted in the unlocked position and its locking pin was off to the side as well (off-center), and it too was soaked in engine oil. Then finally, the destroyed lifter on #8 was nearly bone dry and not even the springs were wet. That thus told me that cylinders #2 and #8 intake lifters were not getting enough oil, meanwhile the 2 MDS lifters (#4 and #6) were soaked in engine oil. So careful examination seems to suggest insufficient oil to the non MDS lifters on Bank 2, while more than ample oil on the MDS lifters (Bank 2). This is why my theory concluded that the reason for failure had to do with the MDS lifters robbing engine oil pressure just on the bank 2 valve train system. I did not mean to suggest that the rest of the engine suffered oil starvation; only the valve train system will likely be impacted when an MDS lifter fails to lock. An unlocked lifter when it should be locked will lead to wasted oil pressure on the specific MDS lifter, and thereby reduce the amount of oil pressure to the rest of the valve train on the same bank. Keep in mind this does not mean that the rest of the engine would suffer oil loss.

I will have to look at the plumbing galley for the hemi engine. I know the oil pump is at the bottom and a tube feeds Bank 1, and a separate tube feeds bank 2. The first valve train to receive oil is from the first cylinder to the last cylinder of the applicable banks. Otherwise, it makes no sense trying to understand why 2 lifters on Bank 2 were heavily soaked with oil, but the other 2 lifters (intake lifters) were nearly dry.

Lastly, I have motored this engine at idle with the valve covers off, and I saw the same results. Oil oozed out near the center of the head on Bank 2 (Passenger side), but nothing on Cylinder 8, and very little on cylinder 2.

At the same time, I can see a valve train issue with soft springs, leading to lifter float, and that of course would cause roller damage. I can only surmise that the reason Chrysler engineers chose to use softer spring loads is to minimize the valve seat stress on the aluminum heads, and also decrease drag in order to enhance fuel efficiency.

Maybe this is all the result of flawed lifters from what ever country they were manufactured. But I'm not convinced this is the case because we would see random lifters dropping out all over the engine, and impacting nearly every hemi engine. Thus, I believe this is primarily limited to the MDS engines, and possibly some non-MDS engines suffering failure. But this I am convinced of. So far, all who have upgarded their hemi's to the Comp-Camshaft, Hellcat lifters, oil plugs, and ECM flash, have not had a repeat of camshaft or lifter failure.


If you had a 1 in 10,000 lifter failure rate, you'd likely only have an engine impacted by one lifter, which likely corresponds with the failure rate being observed. Also, it does seem to require a fair deal of mileage/hours before it happens, which, if it was solely due to starvation, you'd think would happen earlier on, particularly since we know it happens on non-MDS engines too, even if not in the same quantity

Regarding the upgrades: Since the failures usually require significant mileage before occurring, how many of those people that have swapped out their parts have since accrued that same amount of mileage? I'm interested to see if any of the HellCat lifters fail once there are enough out there with high miles on them, that'd be a real tell, though the 6.1L failures are pretty [censored] in themselves, as those engines also had billet steel camshafts.

Originally Posted by JosephA
Was it because MDS was deleted? That seems to be the case, IMHO. Then again, it might be as you have suggested....poorly designed lifters using cheap parts. If it had anything to do with the valve springs, I would assume we'd see more lifter failures even with the upgraded lifters and camshafts. So far, I have not read of any upgraded engine failures.

Joe


It's possible it's also a combination of weak springs and needle-bearing lifters that aren't tolerant of anything resembling float. Heck, if we toss a marginal oil delivery system in there it's a potential recipe for a perfect storm that may require all three things simultaneously to propagate. It's definitely an interesting topic.

 

[OVERKILL]

BTW, so far this is the only 5.7L MDS HEMI oiling diagram I could find:

It seems to show that there are four runs up to the heads to feed the rocker shafts and that each of those runs has a solenoid tapped into it for the MDS and would also seem to feed, separately, the non-MDS lifter galleys.

These diagrams from the Jeep site also seem to help a bit:

I'll update if I find anything else.

 

[JosephA]

Originally Posted by OVERKILL
BTW, so far this is the only 5.7L MDS HEMI oiling diagram I could find:

It seems to show that there are four runs up to the heads to feed the rocker shafts and that each of those runs has a solenoid tapped into it for the MDS and would also seem to feed, separately, the non-MDS lifter galleys.

These diagrams from the Jeep site also seem to help a bit:

I'll update if I find anything else.


The images you've provided look good. The bottom image you posted shows the travel path of the engines oil through the tube after the oil filter. The first cylinder lifters to be lubed on bank 2 are #2, then 4, then 6, and finally 8; it's the same with bank 1.

Here's a video showing how the MDS system works.

How MDS works

What's nuts about this technology is the use of oil pressure to expand the lifters on demand. This to me would seem to suggest that even oil pressure throughout the entire Bank 1 and Bank 2 valve train is temporarily reduced as the lifters are forced to expand. Once the MDS lifters expand, even oil pressure to the valve train is restored. However, it is my theory that when an MDS lifter fails to expand and lock, oil pressure is needed to sustain an expanded position. While the lifter expansion isn't as strong as the locked expansion, the lifter might still function, albeit at a degraded capacity, and hence causing the infamous "Hemi-Tick". When the lifter rotates due to internal guide failure (made of plastic unfortunately), the bottom half of the lifter might rotate, and make it impossible for the lifter to lock. The roller is thus subjected to uneven forces and the stress causes the roller to wear out incorrectly. Eventually the roller will fail and break, leaving FOD all inside of the engine and potentially damaging other components.

On my engine, #8 was completely destroyed and it's 1/3 of the roller is missing (inside of the engine), and all of its associated needle bearings were gone (also within the engine). The 2 MDS lifters for bank one had chaffed rollers, and one roller with a great deal of slop (up and down, side to side play); this despite plenty of engine oil. The cause is due to riding the camshaft lobe off-center.

Joe

 

[OVERKILL]

I saw that video on youtube, but didn't find it sufficiently detailed the oil paths as shown in the first diagram, which appears to show four paths that break off from the main gallery that feeds both the mains and cam bearings, which makes sense when you consider the 4 solenoids. I'd like to find a better diagram though to confirm what I'm seeing. And yes, I'd expect, given the size of the feeds coming from the main gallery, that there would be a momentary "blip" in oil pressure (which should be compensated for almost immediately due to the positive displacement nature of the oil pump) at the feeds for the lifters for the remaining cylinders when the solenoids open. I would not however, expect that this would be enough to compromise lubrication. These aren't ultra high stress locations, and this would/should only be an issue if lubrication in these areas was marginal in the first place.

I understand the reasoning behind your analysis, but that doesn't in any way explain the failure on non-MDS engines

I wonder if the 6.1L used the same lifters? I know the 6.4L does.

 

[JosephA]

Originally Posted by OVERKILL
I saw that video on youtube, but didn't find it sufficiently detailed the oil paths as shown in the first diagram, which appears to show four paths that break off from the main gallery that feeds both the mains and cam bearings, which makes sense when you consider the 4 solenoids. I'd like to find a better diagram though to confirm what I'm seeing. And yes, I'd expect, given the size of the feeds coming from the main gallery, that there would be a momentary "blip" in oil pressure (which should be compensated for almost immediately due to the positive displacement nature of the oil pump) at the feeds for the lifters for the remaining cylinders when the solenoids open. I would not however, expect that this would be enough to compromise lubrication. These aren't ultra high stress locations, and this would/should only be an issue if lubrication in these areas was marginal in the first place.

I understand the reasoning behind your analysis, but that doesn't in any way explain the failure on non-MDS engines

I wonder if the 6.1L used the same lifters? I know the 6.4L does.


Good analysis. And thanks for responding.

Under normal operation, the momentary blip is insufficient to cause a lack of lubrication to the lifters. However, if an MDS lifter fails to lock (which seems to be the case, particularly with my engine), likely due to the lower half and the internal parts of the locking mechenism twist/rotate off center, the lifter cannot lock and thus the higher oil pressure needed to keep the MDS lifters expanded is wasted, thus leading to oil starvation on the rest of the valve train. I noted this after tearing into my engine. The 2 inner cylinders on Bank 2 (#4 and #6) were soaked with oil, but were stuck in a rotated unlocked position. I'll post some pictures this evening of the 2 lifters I'm referring to. Meanwhile, the other two intake lifters for the non-mds cylinders (#2 and #8) were nearly dry, as though they were not getting enough oil. #8 was destroyed, and #2 showed minimal wear. #8 intake lifter lost its needle bearings and almost half of the roller. The lifter also showed signs of scaring on its edges. This clearly suggests an oil starvation issue, likely during long idle operations; my wife does have a tendency to idle the engine.

Joe

 

[OVERKILL]

Originally Posted by JosephA
Originally Posted by OVERKILL
I saw that video on youtube, but didn't find it sufficiently detailed the oil paths as shown in the first diagram, which appears to show four paths that break off from the main gallery that feeds both the mains and cam bearings, which makes sense when you consider the 4 solenoids. I'd like to find a better diagram though to confirm what I'm seeing. And yes, I'd expect, given the size of the feeds coming from the main gallery, that there would be a momentary "blip" in oil pressure (which should be compensated for almost immediately due to the positive displacement nature of the oil pump) at the feeds for the lifters for the remaining cylinders when the solenoids open. I would not however, expect that this would be enough to compromise lubrication. These aren't ultra high stress locations, and this would/should only be an issue if lubrication in these areas was marginal in the first place.

I understand the reasoning behind your analysis, but that doesn't in any way explain the failure on non-MDS engines

I wonder if the 6.1L used the same lifters? I know the 6.4L does.


Good analysis. And thanks for responding.

Under normal operation, the momentary blip is insufficient to cause a lack of lubrication to the lifters. However, if an MDS lifter fails to lock (which seems to be the case, particularly with my engine), likely due to the lower half and the internal parts of the locking mechenism twist/rotate off center, the lifter cannot lock and thus the higher oil pressure needed to keep the MDS lifters expanded is wasted, thus leading to oil starvation on the rest of the valve train. I noted this after tearing into my engine. The 2 inner cylinders on Bank 2 (#4 and #6) were soaked with oil, but were stuck in a rotated unlocked position. I'll post some pictures this evening of the 2 lifters I'm referring to. Meanwhile, the other two intake lifters for the non-mds cylinders (#2 and #8) were nearly dry, as though they were not getting enough oil. #8 was destroyed, and #2 showed minimal wear. #8 intake lifter lost its needle bearings and almost half of the roller. The lifter also showed signs of scaring on its edges. This clearly suggests an oil starvation issue, likely during long idle operations; my wife does have a tendency to idle the engine.

Joe


No problem. A few thoughts:

- I would think that if the MDS isn't properly activating, and thus just essentially "pumping in place" with the solenoid open, that you would see a ton of oil on those effected units, because you'd have this motion that you wouldn't have with a regular lifter, which should maintain regular resistance to oil supply.
- I just have a hard time with this leak being large enough to cause starvation unless the gallery feeds are massively undersized, because in this scenario, system-wide pressure would be dropping, and thus visible on a gauge.
- I would also expect starvation on the rocker shafts, since they are the furthest point from that main gallery, and run off what appear to be the same feeds.
- Also, if the non-MDS lifters aren't being sufficiently pressurized, oil through the pushrods would also be significantly reduced/eliminated.

Looking forward to seeing the pictures.

 

[JosephA]

Quote
No problem. A few thoughts:

- I would think that if the MDS isn't properly activating, and thus just essentially "pumping in place" with the solenoid open, that you would see a ton of oil on those effected units, because you'd have this motion that you wouldn't have with a regular lifter, which should maintain regular resistance to oil supply.
- I just have a hard time with this leak being large enough to cause starvation unless the gallery feeds are massively undersized, because in this scenario, system-wide pressure would be dropping, and thus visible on a gauge.
- I would also expect starvation on the rocker shafts, since they are the furthest point from that main gallery, and run off what appear to be the same feeds.
- Also, if the non-MDS lifters aren't being sufficiently pressurized, oil through the pushrods would also be significantly reduced/eliminated.

Looking forward to seeing the pictures.


That is exactly what I found when I first removed the lifters, and that's when I came to the conclusion that the MDS lifters were wasting oil pressure for the valve train on Bank 2 (Passenger side). The 2 stuck lifters (unlocked) were drenched with oil. Meanwhile, the #8 Intake lifter was nearly bone dry and thus the reason for it's total destruction of the roller, which also showed signs of chaffing on its edges. The intake lifter on Cylinder 2 (again bank 2) had some oil, but minor scaring on the roller. I'll post the pictures momentarily.

Cylinder #8 Lifter which was dry and missing all of the needle bearings plus about 1/3 of the roller bearing. It was nearly dry when I pulled out this lifter

MDS Lifter for Cylinder #4 - Notice the severe scarring of the roller. This lifter was stuck in the unlocked position and was also drenched in oil

MDS Lifter for Cylinder #6 - Notice the roller scarring and the lock pin off center - this lifter was also drenched in oil

Cylinder #8 Lifter - Again showing total destruction of the roller and its needle bearings. The debris is somewhere in the engine...

As you can see, the #4 and #6 Lifters were stuck in the unlocked position with the locking pins off center and the lower half of the lifters were rotated, and thus causing severe chaffing of the roller as seen by the damage. And #8 was completely destroyed. I did not include the lifter for Cylinder #2 since minimal damage was noticed. There was minor scaring on the #2 intake lifter but not as severe as the rest.

All the lifters for Bank 1 (Driver side) were very good, with slight exception to Cylinder #1 intake lifter which also had minor scarring. And all the lifters on Bank 1 were very wet with oil.

So the question remains. Why were the solid lifters for Cylinders 2 and 8 nearly dry, while the MDS lifters for Cylinders 4 and 6 were soaking wet? While the photo's do not show oil saturation at the time of removal (naturally I wiped them all down for inspection), my stated oil conditions of the lifters were noted upon removing them. There can only be one explanation, and it is a logical conclusion. For some reason, Cylinders 2 and 8 intake lifters did not receive sufficient lubrication. And it is my strongest opinion that the MDS lifters were hogging up wasted oil volume due to both lifters being stuck in the unlocked position, the poppet hole being left open allowed for additional oil volume to saturate the 2 lifters since they both failed to lock. Had the lifters locked, then no additional oil pressure and volume would have been lost, and the entire valve train would have functioned as usual.

Joe

 

[OVERKILL]

Originally Posted by JosephA
Quote
No problem. A few thoughts:

- I would think that if the MDS isn't properly activating, and thus just essentially "pumping in place" with the solenoid open, that you would see a ton of oil on those effected units, because you'd have this motion that you wouldn't have with a regular lifter, which should maintain regular resistance to oil supply.
- I just have a hard time with this leak being large enough to cause starvation unless the gallery feeds are massively undersized, because in this scenario, system-wide pressure would be dropping, and thus visible on a gauge.
- I would also expect starvation on the rocker shafts, since they are the furthest point from that main gallery, and run off what appear to be the same feeds.
- Also, if the non-MDS lifters aren't being sufficiently pressurized, oil through the pushrods would also be significantly reduced/eliminated.

Looking forward to seeing the pictures.


That is exactly what I found when I first removed the lifters, and that's when I came to the conclusion that the MDS lifters were wasting oil pressure for the valve train on Bank 2 (Passenger side). The 2 stuck lifters (unlocked) were drenched with oil. Meanwhile, the #8 Intake lifter was nearly bone dry and thus the reason for it's total destruction of the roller, which also showed signs of chaffing on its edges. The intake lifter on Cylinder 2 (again bank 2) had some oil, but minor scaring on the roller. I'll post the pictures momentarily.

Cylinder #8 Lifter which was dry and missing all of the needle bearings plus about 1/3 of the roller bearing. It was nearly dry when I pulled out this lifter

MDS Lifter for Cylinder #4 - Notice the severe scarring of the roller. This lifter was stuck in the unlocked position and was also drenched in oil

MDS Lifter for Cylinder #6 - Notice the roller scarring and the lock pin off center - this lifter was also drenched in oil

Cylinder #8 Lifter - Again showing total destruction of the roller and its needle bearings. The debris is somewhere in the engine...

As you can see, the #4 and #6 Lifters were stuck in the unlocked position with the locking pins off center and the lower half of the lifters were rotated, and thus causing severe chaffing of the roller as seen by the damage. And #8 was completely destroyed. I did not include the lifter for Cylinder #2 since minimal damage was noticed. There was minor scaring on the #2 intake lifter but not as severe as the rest.

All the lifters for Bank 1 (Driver side) were very good, with slight exception to Cylinder #1 intake lifter which also had minor scarring. And all the lifters on Bank 1 were very wet with oil.

So the question remains. Why were the solid lifters for Cylinders 2 and 8 nearly dry, while the MDS lifters for Cylinders 4 and 6 were soaking wet? While the photo's do not show oil saturation at the time of removal (naturally I wiped them all down for inspection), my stated oil conditions of the lifters were noted upon removing them. There can only be one explanation, and it is a logical conclusion. For some reason, Cylinders 2 and 8 intake lifters did not receive sufficient lubrication. And it is my strongest opinion that the MDS lifters were hogging up wasted oil volume due to both lifters being stuck in the unlocked position, the poppet hole being left open allowed for additional oil volume to saturate the 2 lifters since they both failed to lock. Had the lifters locked, then no additional oil pressure and volume would have been lost, and the entire valve train would have functioned as usual.

Joe


So does this not beg the question why the rollers that are drenched in oil still experienced massive damage to the rollers?

 

[JosephA]

Quote
So does this not beg the question why the rollers that are drenched in oil still experienced massive damage to the rollers?


At first, I wondered the same thing. The answer was obvious when I recognized the lower end of each of the MDS lifters was rotated, and the locking tabs were off center. This was also the reason for the Hemi-Tick since neither lifter were expanded to the fullest extension. So there was lifter float, and rotated rollers riding the camshaft lobes at a slight angle. In time, the rollers would likely have been destroyed as the #8 lifter had suffered. It was the banging of the MDS lifters that caused roller damage, combined with the rollers rotating at a slight angle.

I'm not convinced the problem is strictly faulty lifters or its design EXCEPT the MDS lifters and its internal locking/unlocking mechanism; the locking mechanism I'm told utilizes plastic keepers...very stupid idea.

Everyone seems to have forgotten that GM is suffering the exact same problem with lifters failing due to the utilization of the AFM technology. As with Chysler's MDS failures, GM's AFM failures are showing the same results...destroyed lifters and camshafts.

Can it be any more obvious as to the reasons why this kind of technology is leading to expensive failures? Instead, Chrysler continues to play their usual legal games, "It's all about oil changes! No receipts or proof of oil changes, then no assistance". THEN, if the customer DOES prove oil changes, they then try resorting to accusations of poor driving habits, i.e. hot dogging, long idle times, blah blah blah.

Chrysler has proven time and time again the consumers are only important when their bank accounts are emptied. And to-date, Chrysler represents the worst of all the automotive industry, and refusing to own up to its costly mistakes, and leaving consumers to pay the bill.

I've been screwed 3 times now by Chrysler, and I promise that will never happen again. NEVER! I've owned 2 prior troublesome Dodge products, both of which failed prematurely. Yet despite routine oil changes, both engines failed far too soon.

I feel Chrysler should pay back the tax payers for all of the bailout money they stole from the American tax payers. And they should absorb 100% percent of the costs associated with these camshaft and lifter failures. Own up to the product they crapped out of their a-holes.

Joe

 

[dave1251]

With the history of the HEMI failure going back pre MDS with the same type of failure it's not MDS.

 

[tiger862]

I looked at these lifters you put and I can guarantee that a new set of lifters will not fix. The lifter bore is out of spec. I see lifter wear at bore so lifter is moving and binding. Your oil loss theory is interesting but I would have to remove engine and have bore fixed as well as cam journal.

 

[burla]

How was the cam lob Joseph? Sorry if you mentioned it already, I didn't catch all of that info.

 

[OVERKILL]

Originally Posted by dave1251
With the history of the HEMI failure going back pre MDS with the same type of failure it's not MDS.


Yes, I've mentioned that a couple of times now.

 

[OVERKILL]

Originally Posted by JosephA
Quote
So does this not beg the question why the rollers that are drenched in oil still experienced massive damage to the rollers?


At first, I wondered the same thing. The answer was obvious when I recognized the lower end of each of the MDS lifters was rotated, and the locking tabs were off center. This was also the reason for the Hemi-Tick since neither lifter were expanded to the fullest extension. So there was lifter float, and rotated rollers riding the camshaft lobes at a slight angle. In time, the rollers would likely have been destroyed as the #8 lifter had suffered. It was the banging of the MDS lifters that caused roller damage, combined with the rollers rotating at a slight angle.

Joe


I need some further clarification here.

Are you saying the lifter body rotated/twisted? Because the body is a single piece, so the only way that is happening is if the (plastic) guide isn't keeping it straight, and that problem wouldn't be MDS-specific, since the same retaining unit/guide is used for both MDS and non-MDS lifters.

Now, as I am sure we can agree, the internals intentionally collapse when MDS is activated, that's how the system works. I agree that in your pictures the internals have obviously twisted, but was the section that engages the pushrod still "up"? I would expect in that situation you'd just end up in a quasi-permanent MDS state, which wouldn't be any more inclined to float than typical MDS operation, unless there was serious internal bind taking place, which, from the design, pictures, doesn't look like it would be easily achievable.

I mean, essentially, you are describing two completely different failure scenarios taking place simultaneously:
- Lifters are being starved of oil, causing them to fail
- MDS lifters are failing internally, bathing themselves in oil, but also failing, the theory being that wear we are seeing is due to float and/or twisting, the latter which would imply an issue with the guide mechanism for keeping the lifters straight.

Is it not possible that the material being shed by the failing lifter is making its way to its neighbours and causing the wear/damage we are observing on these rollers and potentially the reason for the MDS malfunction? I don't think it is out of the realm of possibility. In this case, it would then also explain the presence of the issue on non-MDS engines.

I've mulled this over myself, hence the theories I presented at the onset of this discussion. The problem is that we need a failure mode that works in all situations:
- When a non-MDS lifter, that may look properly lubricated, in an MDS engine fails
- When an MDS lifter in an MDS engine fails
- When a non-MDS lifter in a non-MDS engine fails

What are the common parts?
- The non-MDS lifters
- The lifter guides
- The lube delivery paths (mostly)

What are our potential failure models that could work for all the above?
- I noted it could be float and you seem to have latched onto that somewhat. But I have a hard time picturing that happening on the 6.4L or 6.1L unless Chrysler was cheap with the valve springs. Float hammering the lifters wouldn't care whether they were MDS or not, and needle bearings aren't tolerant of this.
- You noted it could be oil starvation from marginal lubricant system design. This also, assuming that it's a design issue that doesn't care about MDS, is a potential culprit.
- It could be wear of the plastic/nylon lifter guides, allowing them to wiggle/rotate/run off-centre, which could lead to the roller not rolling or skating at an angle, locking up and wiping out both the lobe and lifter
- ?

I think with any of the above theories we need to consider that once a lifter starts failing, it's going to be casting metal bits which are going to end up on adjacent lobes and could lead to cascading failure if not caught quickly.

 

[tiger862]

Originally Posted by OVERKILL
Originally Posted by JosephA
Quote
So does this not beg the question why the rollers that are drenched in oil still experienced massive damage to the rollers?


At first, I wondered the same thing. The answer was obvious when I recognized the lower end of each of the MDS lifters was rotated, and the locking tabs were off center. This was also the reason for the Hemi-Tick since neither lifter were expanded to the fullest extension. So there was lifter float, and rotated rollers riding the camshaft lobes at a slight angle. In time, the rollers would likely have been destroyed as the #8 lifter had suffered. It was the banging of the MDS lifters that caused roller damage, combined with the rollers rotating at a slight angle.

Joe


I need some further clarification here.

Are you saying the lifter body rotated/twisted? Because the body is a single piece, so the only way that is happening is if the (plastic) guide isn't keeping it straight, and that problem wouldn't be MDS-specific, since the same retaining unit/guide is used for both MDS and non-MDS lifters.

Now, as I am sure we can agree, the internals intentionally collapse when MDS is activated, that's how the system works. I agree that in your pictures the internals have obviously twisted, but was the section that engages the pushrod still "up"? I would expect in that situation you'd just end up in a quasi-permanent MDS state, which wouldn't be any more inclined to float than typical MDS operation, unless there was serious internal bind taking place, which, from the design, pictures, doesn't look like it would be easily achievable.

I mean, essentially, you are describing two completely different failure scenarios taking place simultaneously:
- Lifters are being starved of oil, causing them to fail
- MDS lifters are failing internally, bathing themselves in oil, but also failing, the theory being that wear we are seeing is due to float and/or twisting, the latter which would imply an issue with the guide mechanism for keeping the lifters straight.

Is it not possible that the material being shed by the failing lifter is making its way to its neighbours and causing the wear/damage we are observing on these rollers and potentially the reason for the MDS malfunction? I don't think it is out of the realm of possibility. In this case, it would then also explain the presence of the issue on non-MDS engines.

Thank you Overkill as you stated what I noticed. A twist as he called it along with oil starvation you can have bore issues. For this reason engine needs to go to machine shop. Parts for complete overhaul as well as cam and lifters. You could possibly put cam and lifters in but that is only going to be a bandaid without finding root causes.

 

[burla]

There has been guys that change lifters only to still have the tick, some changed lifters because of the tick and before any failures. But, also many guys have just changed lifters and had tick disappear, and cam and lifters and also had tick disappear. There is no uniform block tolerance issue, but it certainly makes sense that is part of it. dyi cam install. Not for you Joseph as you already can do your own, but in case someone else wants to give it a go. Out of warranty cam/lifters have ranged from 3900 to 12,000 from the dealer, most in the 5/6 grand range. More ticks are repoted every week, these things are failing at a high rate, most right out of warrarty, it is usually 70k to 150k miles. Both ram forums have extended info, but it is good to see more discusion here. This problem is just gonna get worse as these trucks age.

 

[JosephA]

Originally Posted by dave1251
With the history of the HEMI failure going back pre MDS with the same type of failure it's not MDS.


Prior to 2007'ish, there were no lifter/camshaft failures with the hemi; this didn't start until the introduction of the MDS. Prior to 2007, the biggest problem they had with the earlier Hemi designs were dropping valve seats, which seemed to be predominately happening on the Chrysler 300's.

Joe

 

[JosephA]

Originally Posted by tiger862
I looked at these lifters you put and I can guarantee that a new set of lifters will not fix. The lifter bore is out of spec. I see lifter wear at bore so lifter is moving and binding. Your oil loss theory is interesting but I would have to remove engine and have bore fixed as well as cam journal.


You might be correct and that is why I have not ordered new parts yet. I told my wife it's best to just yank the engine. Heck I only have to remove the Transmission bolts since the entire engine has been gutted. LOL I thought of going to a jasper engine, but their reputation sucks to say the least.

One thing is for certain. I will NOT be installing the MDS garbage. The technology just do not work, and the little savings you supposedly get from the MDS in fuel, is lost in damage/destruction/repair. Thus, MDS is a wasted technology that is not reliable; so much so that even GM is having the same issues with their AFM (cylinder deactivation) technology.

Joe

 

[JosephA]

Originally Posted by burla
How was the cam lob Joseph? Sorry if you mentioned it already, I didn't catch all of that info.


I will yank the cam out this weekend. But I was able to view the camshaft lobe for #8 and it was damaged. Thankfully I got the problem just in time and told the wife not to drive it anymore just as soon as it lost power and started knocking. So I used an 8mm flex-scope and viewed the cam from the lifter bore, and it's damaged; the same with the MDS bores on cylinders 4 and 6. When I remove the cam this weekend, I'll be sure to post photo's

Joe

 

[JosephA]

Quote
I need some further clarification here.

Are you saying the lifter body rotated/twisted? Because the body is a single piece, so the only way that is happening is if the (plastic) guide isn't keeping it straight, and that problem wouldn't be MDS-specific, since the same retaining unit/guide is used for both MDS and non-MDS lifters.


Yes, the lifter is twisted. Look at the image I posted earlier and you will notice the lock pin is not centered with the hole, and the bottom roller is not quite in line with the top half of the lifter.