Ram Hemi hydraulic lifter failure...oil related?

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OVERKILL is correct on his understanding of the MDS operation. Oil pressure applied to the pins allows the lifter assembly to collapse, but it's simply a regular style hydraulic lifter INSIDE the body of another lifter. The pins remaining stuck in would simply make those cylinders de-activated permanently, and not constitute an oil leak draining the main lifter gallery. Lock pin doesn't HAVE to line up with the hole as shown in the majority of the pics, as the ledge that it locks on is an entire gallery circumferentially around the inside of the "outer" lifter.
 
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Originally Posted by 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.
We have 5x HEMI RAM's at work between 2011 and 2012, all with MDS. We also have a 2014 and 2015. One of those trucks has rod knock, all of them have >240,000Km on them (150K miles) absolutely none of them have had a lifter issue. Every single one of the older trucks has needed to have the exhaust studs and gaskets replaced. Actually, I don't know a single person that has had to have their lifters done shrug I know it happens, but it is infrequent enough that nobody in my circle of hemi owners has experienced it. IIRC, the Comp lifter failures was due to them outsourcing them to China. Ford had excellent service from their OEM lifters, which were made by Eaton I believe.
 
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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.
You are correct. But is the oil pressure maintained throughout the deactivation operation? Or is the oil pressure removed once the pin is unlocked? Get my point? Oil pressure is needed to keep the system unlocked. Now I might be incorrect about the oil pressure being used to the last possible second just prior to MDS deactivation; this is possibly to help ensure the lifter reaches maximum expansion. And as soon as the lock pin is just about to lock, the solenoid is deactivated and oil flow to the lifter through the solenoid is blocked, leading to a locked lifter. Now then, if the oil from the solenoid is cutoff during full engine operation (all 8 cylinders), this would mean that the lifters are receiving lubrication normally by another means; the same means the non-MDS lifters receive oil. And this oil must lubricate both the outside of the lifter (body, rollers, etc.), and likewise as a standard lifter, travel through the inside of the lifter to form a path to the push rods, which in turn lubricates rockers and valve springs, etc. The point is, the lifter must maintain lubrication. And what happens when the lubrication is compromised by a opened hole on the lifter where the lockpin would ordinarily be closed? It's going to leak into the lifter itself. Now using physics 101, would this not equate to a drop in volume flow, and hence a reduction in oil flow velocity? Put it to you like this. Oil pressure can be used to indicate the age of an engine. As bearings and parts where down, oil pressure will drop due to less resistance between the journals, bearings, lifters, cylinder walls, etc. In the case of the Hemi lifters, if the lock pin is stuck open, then that is the same as a worn bearing; oil travel to that specific part of the system will be reduced in speed, while increased in volume. And a drop in oil pressure/volume to any part of the engine will equate to losses else wear as lower RPM's. Now unless you want to explain how the MDS lifters are lubricated both during locked and unlocked operation, I fail to see how you are not grasping or understanding what I'm trying to explain. I will admit my error with MDS operation with regards to the lower half and the upper half of the lifter. I initially assumed the lower end of the lifter is what bobs up and down while the middle half remains stationary. I was wrong. I now understand that the lifter itself remains stationary (through the plastic keepers which might be the culprit causing some slight rotation), and the internals from the top down to the bottom inside the lifter collapse in on itself and the push rod is basically "having sex" figuratively speaking. LOL So then, back to the point. If the MDS oil solenoid only "spurts" oil just long enough to unlock the pin, then the lifter must remain unlocked by some other means. However, this is not the case. Oil pressure from the MDS solenoid must remain opened during the entire cylinder-deactivation operation in order to keep the MDS lifters from locking back into place. And THIS ladies and gentlemen is what I've been trying to explain to you all and this is what's causing lubrication problems throughout the rest of the valve train. Once the solenoid opens oil pressure to unlock the lifter, this pressure is maintained throughout the entire time of MDS operation which prevents the lifter from locking back into place; the video I posted shows this. Once the driver demands more power, the solenoid remains open just long enough as the lifter is expanding, and oil pressure is cut to allow the internal lock pin to lock. If the lock pin does not lock, then oil (normal oil lubrication during extended use) is wasted on those lifters. And THIS is why we do not see lifter/camshaft damage prior to MDS and DOD introduction. Joe
 
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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.
My question wasn't an explanation of how I understand oil or back pressure. It was a question for you as I did not understand where you personally are at with regards to oil operation. As stated, I do understand how the MDS lifter works and that the oil pressure is sustained throughout the entire MDS operation in order to keep the lifter from locking, which also contributes to its expansion on the very last stroke just prior to lifter-lock. And THAT is where the problem is being caused. When an MDS lifter is collapsed, oil pressure must be maintained throughout the entire time the engine is in economy mode. The problem is also compounded when the lifter fails to lock, thereby causing a free-floating lifter, and normal oil losses due to a hole on the lifter, and hence a reduction in oil flow velocity (with an increase in oil volume), and hence degradation to the rest of the valve train. The only thing I was wrong about is what parts move on the lifter until I examined the image you posted. Now we are getting somewhere. Joe
 
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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.
None of the lifters (both the hellcat and the stock 5.7 MDS and non-MDS lifters) are available for at least 2 to 3 months. My apologies for not clarifying this. The dealerships are not modifying the engine. Any Hemi that come in for repair are being repaired to factory level. But those like me, who are doing their own work, are relying on the upgrades recommended by Comp-Cam, Johnson, and MMX, and so the thousands of us who are performing the upgrades are trying to get our hands on hellcat lifters, and they too are on back order. So both the stock lifters and the hellcast lifters are on back order. This means one [censored] of a scramble by the US (and possibly the rest of the Hemi owning world) that we are in a panic to fix our freaking trucks. There is a high demand for these lifters, but insufficient supply to fill them. High demands means high event of failures. This is a fact. Joe
 
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Originally Posted by JosephA
So then, back to the point. If the MDS oil solenoid only "spurts" oil just long enough to unlock the pin, then the lifter must remain unlocked by some other means. However, this is not the case. Oil pressure from the MDS solenoid must remain opened during the entire cylinder-deactivation operation in order to keep the MDS lifters from locking back into place. And THIS ladies and gentlemen is what I've been trying to explain to you all and this is what's causing lubrication problems throughout the rest of the valve train. Once the solenoid opens oil pressure to unlock the lifter, this pressure is maintained throughout the entire time of MDS operation which prevents the lifter from locking back into place; the video I posted shows this. Once the driver demands more power, the solenoid remains open just long enough as the lifter is expanding, and oil pressure is cut to allow the internal lock pin to lock. If the lock pin does not lock, then oil (normal oil lubrication during extended use) is wasted on those lifters. And THIS is why we do not see lifter/camshaft damage prior to MDS and DOD introduction. Joe
Nope...you don't get the operation at all The MDS solenoid, through a lifter that doesn't unlock, nor a lifter that fails to lock in an un MDS state is not an oil leak.
 
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Originally Posted by JosephA
You are correct.
I know, I've been clear on how the system operates from the start.
Originally Posted by JosephA
But is the oil pressure maintained throughout the deactivation operation?
The oil pressure, at the orifice, is NECESSARY to keep the pin unlocked. So it is maintained until the solenoid closes, which in turn shuts off the MDS.
Originally Posted by JosephA
Or is the oil pressure removed once the pin is unlocked? Get my point? Oil pressure is needed to keep the system unlocked.
I've been clear about that the entire time.
Originally Posted by JosephA
Now I might be incorrect about the oil pressure being used to the last possible second just prior to MDS deactivation; this is possibly to help ensure the lifter reaches maximum expansion. And as soon as the lock pin is just about to lock, the solenoid is deactivated and oil flow to the lifter through the solenoid is blocked, leading to a locked lifter.
And this is where you still don't get it. How is the pin about to lock if the system is still pressurized? It isn't! You've got it backwards. It's the solenoid cutting off the pressure to the orifices that enables the pin to slide back into place, disabling the MDS. Oil pressure turns on, and keeps on, the MDS. Once that pressure is removed, the pin slides back into place on the next cycle, disabling MDS.
Originally Posted by JosephA
Now then, if the oil from the solenoid is cutoff during full engine operation (all 8 cylinders), this would mean that the lifters are receiving lubrication normally by another means; the same means the non-MDS lifters receive oil. And this oil must lubricate both the outside of the lifter (body, rollers, etc.), and likewise as a standard lifter, travel through the inside of the lifter to form a path to the push rods, which in turn lubricates rockers and valve springs, etc. The point is, the lifter must maintain lubrication. And what happens when the lubrication is compromised by a opened hole on the lifter where the lockpin would ordinarily be closed? It's going to leak into the lifter itself. Now using physics 101, would this not equate to a drop in volume flow, and hence a reduction in oil flow velocity?
For what must be the 5th time now, where is the oil going to leak to? You keep envisioning the part of the lifter that the solenoid feeds as a black hole, where oil disappears. It's a small hole in the side of the lifter body with a pin, in a cylinder, which it slides in, that, once under pressure, results in that pin sliding backwards a tiny amount to unlock. If the internal mechanism rotates out of alignment with the hole, it doesn't matter, as the small relief in the body that the pin engages is circumferential and when that relief is under pressure, the pin will be displaced.There is no additional path for the oil to follow. Some may squeeze between the body and the bore, but that amount would be quite small. I'm going to try and explain this with a diagram: [Linked Image] 1. This is the standard feed hole present on all 16 lifters that ties into the lifter feed galleries. These are always under pressure providing oil through the body of the lifter, to the roller, and through the pushrod. 2. This is the relief for the MDS pin. It runs around the entire inside of the body, so even if the pin is not aligned with the hole, this is under pressure when the solenoid is live 3. These are the oil paths fed by #1 4. This is the solid block that holds the MDS pin, spring, and the chamber within which this slides. This is essentially the "lifter inside a lifter" that slides up and down when the pin is unlocked. 5. These are the plastic guides we discussed earlier that keep the lifters in-line with the camshaft
Originally Posted by JosephA
Put it to you like this. Oil pressure can be used to indicate the age of an engine. As bearings and parts where down, oil pressure will drop due to less resistance between the journals, bearings, lifters, cylinder walls, etc.
Typically, journals, which are hard, don't wear. It's the bearings that wear, opening up the clearance, resulting in more side-leaking, which in turn lowers oil pressure. Cylinder walls aren't pressure-lubricated, they are lubed with a spray that comes from between the rod and crank. A worn bore will have zero impact on oil pressure.
Originally Posted by JosephA
In the case of the Hemi lifters, if the lock pin is stuck open, then that is the same as a worn bearing; oil travel to that specific part of the system will be reduced in speed, while increased in volume. And a drop in oil pressure/volume to any part of the engine will equate to losses else wear as lower RPM's.
No, it's nothing like that at all. If the pin is stuck open, that lifter simply stays in MDS mode. However, the pin can't be stuck and MDS be on, as the MDS activation depends on the pin being displaced, and thus pressure being provided to the MDS orifice on the lifter body. If the pin sticks, it sticks on MDS disengagement, that is, when the solenoid CUTS OFF, the oil pressure to the lifter, but the pin does not return to the locked position, leaving that lifter in MDS operation.
Originally Posted by JosephA
Now unless you want to explain how the MDS lifters are lubricated both during locked and unlocked operation, I fail to see how you are not grasping or understanding what I'm trying to explain.
You first need to get a handle on how these things function. I've already explained how everything is lubricated, it's your turn to digest that information.
Originally Posted by JosephA
I will admit my error with MDS operation with regards to the lower half and the upper half of the lifter. I initially assumed the lower end of the lifter is what bobs up and down while the middle half remains stationary. I was wrong. I now understand that the lifter itself remains stationary (through the plastic keepers which might be the culprit causing some slight rotation), and the internals from the top down to the bottom inside the lifter collapse in on itself and the push rod is basically "having sex" figuratively speaking. LOL
I still don't think you follow this part. The lifter body is a solid piece, just like a conventional lifter, that, when the engine is rotating, follows the profile of the camshaft. This is the case whether MDS is engaged or not. The entire body moves up and down, kept in alignment by the plastic guide at the top, just like the non-MDS lifters. When the solenoids receive power and pressurize the MDS orifices, the lock pins are displaced and the solid assembly that is inside the lifter body; essentially the "lifter inside the lifter", becomes detached from the main body, remaining stationary while the spring that is below it keeps sufficient pressure on it to keep the pushrod in location and allow for conventional oiling to continue through it.
Originally Posted by JosephA
So then, back to the point. If the MDS oil solenoid only "spurts" oil just long enough to unlock the pin, then the lifter must remain unlocked by some other means. However, this is not the case. Oil pressure from the MDS solenoid must remain opened during the entire cylinder-deactivation operation in order to keep the MDS lifters from locking back into place. And THIS ladies and gentlemen is what I've been trying to explain to you all and this is what's causing lubrication problems throughout the rest of the valve train. Once the solenoid opens oil pressure to unlock the lifter, this pressure is maintained throughout the entire time of MDS operation which prevents the lifter from locking back into place; the video I posted shows this. Once the driver demands more power, the solenoid remains open just long enough as the lifter is expanding, and oil pressure is cut to allow the internal lock pin to lock.
1. The above again assumes there is an oil black hole that results in pressure loss. This is not the case as I've explained. 2. Once something happens, whether it is the driver hitting the pedal or encountering a grade to increase load, the solenoid has the power removed from it, which ceases the pressure being applied to the MDS orifices, which then allows the springs behind the lock pins to push the pins back into their grooves, making the lifters single units again. The solenoid does not, in any part of this, "remain open" when MDS is called to be deactivated. It is the cessation of oil pressure caused by the solenoid being deactivated that allows the pin to seat, thus disabling MDS.
Originally Posted by JosephA
If the lock pin does not lock, then oil (normal oil lubrication during extended use) is wasted on those lifters. And THIS is why we do not see lifter/camshaft damage prior to MDS and DOD introduction. Joe
If the lock pin does not lock, that lifter remains in MDS operation, which would be noticeable. Everything else would operate normally. And I've provided numerous examples that show lifter failure happens on non-MDS engines, you claiming that it doesn't at this juncture is utterly ridiculous.
 
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Originally Posted by Shannow
Originally Posted by JosephA
So then, back to the point. If the MDS oil solenoid only "spurts" oil just long enough to unlock the pin, then the lifter must remain unlocked by some other means. However, this is not the case. Oil pressure from the MDS solenoid must remain opened during the entire cylinder-deactivation operation in order to keep the MDS lifters from locking back into place. And THIS ladies and gentlemen is what I've been trying to explain to you all and this is what's causing lubrication problems throughout the rest of the valve train. Once the solenoid opens oil pressure to unlock the lifter, this pressure is maintained throughout the entire time of MDS operation which prevents the lifter from locking back into place; the video I posted shows this. Once the driver demands more power, the solenoid remains open just long enough as the lifter is expanding, and oil pressure is cut to allow the internal lock pin to lock. If the lock pin does not lock, then oil (normal oil lubrication during extended use) is wasted on those lifters. And THIS is why we do not see lifter/camshaft damage prior to MDS and DOD introduction. Joe
Nope...you don't get the operation at all The MDS solenoid, through a lifter that doesn't unlock, nor a lifter that fails to lock in an un MDS state is not an oil leak.
I disagree. And if I am wrong, then prove it. If the poppet is stuck open, and the solenoid is closed, the lifter still needs lubrication despite the fact that it's not doing much work. Are you assuming that the lifter in MDS mode does not get oil, and that oil only comes from the MDS solenoid? One thing that helps with troubleshooting is understanding the total process of the operation. So I'd like you to explain the entire process of the lubrication of the MDS lifter. Does the solenoid play a factor in lubricating MDS lifters? Or is it soley for pushing in the lock pin so that the internals can free-float via the spring? And if the solenoid does not lubricate the lifter, then the lifter must be getting normal lubrication the same as the non-MDS lifter. And if/since the MDS lifter while in locked mode (solid state) is operating to full capacity, how then is the lifter lubricated? From the bottom up or the top down? I'm trying to get you to understand is oil in a normal valve train travels from the block to the tiny little holes on the side of the lifter. As the lifter slides up and down (say my 5.7 Vortec), oil travels inside of the lifter upward, through the pushrods, and out of the tip of the rod and falls back into the head lubricating also the springs and rockers, where it then falls back into the oil pan. Please explain the entire lubrication process. THEN I think you will see more clearly my point. Joe
 
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Originally Posted by JosephA
I disagree. And if I am wrong, then prove it. If the poppet is stuck open, and the solenoid is closed, the lifter still needs lubrication despite the fact that it's not doing much work. Are you assuming that the lifter in MDS mode does not get oil, and that oil only comes from the MDS solenoid? One thing that helps with troubleshooting is understanding the total process of the operation. So I'd like you to explain the entire process of the lubrication of the MDS lifter. Does the solenoid play a factor in lubricating MDS lifters? Or is it soley for pushing in the lock pin so that the internals can free-float via the spring? And if the solenoid does not lubricate the lifter, then the lifter must be getting normal lubrication the same as the non-MDS lifter. And if/since the MDS lifter while in locked mode (solid state) is operating to full capacity, how then is the lifter lubricated? From the bottom up or the top down? I'm trying to get you to understand is oil in a normal valve train travels from the block to the tiny little holes on the side of the lifter. As the lifter slides up and down (say my 5.7 Vortec), oil travels inside of the lifter upward, through the pushrods, and out of the tip of the rod and falls back into the head lubricating also the springs and rockers, where it then falls back into the oil pan. Please explain the entire lubrication process. THEN I think you will see more clearly my point. Joe
The lifters are all lubricated and the hydraulic lash adjuster component functions the same for both the regular and the MDS lifter. The additional gallery that feeds the MDS pins applies oil to the circumferential gallery inside the lifter outer body, and pushes the pins in causing the traditional lash adjuster component to float in the outer body and not transfer motion to the rockers. It's really VERY simple...and the MDS solenoid does not constitute a leak...
 
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Originally Posted by Shannow
OVERKILL is correct on his understanding of the MDS operation. Oil pressure applied to the pins allows the lifter assembly to collapse, but it's simply a regular style hydraulic lifter INSIDE the body of another lifter. The pins remaining stuck in would simply make those cylinders de-activated permanently, and not constitute an oil leak draining the main lifter gallery. Lock pin doesn't HAVE to line up with the hole as shown in the majority of the pics, as the ledge that it locks on is an entire gallery circumferentially around the inside of the "outer" lifter.
Bingo! We finally got someone to state this. I've been waiting for the others to admit this, and now finally some has. If someone stated this, and I missed it, then my apologies. The lock pin DOES have the line up with the hole for the lifter to "lock". Otherwise, it is not locked. The purpose of the solenoid is to use oil pressure to push the lock pin inwards, thereby enabling the internal part of the lifter to free-float via a spring. And as you correctly stated, the lifter receives its normal lubrication from the "main gallery" as you call it. However, if the hole in the lifter is left open, where do you think that oil is going to go? This all depends on how the MDS lifter gets its lubrication. Are we to assume that MDS lifters are no lubricated in the same way as the solid lifters? If so, then how do the push rods get oil? Or are MDS lifters lubed from the top down, meaning oil comes from the rods, down to the MDS lifters. There are 2 overall points I've been trying to get everyone to understand. These are: 1. All lifters must be lubricated at all times, MDS or non-MDS 2. An MDS lifter with a lock-pin that is off center means that it cannot lock. And my theory is the normal lubrication (if any during MDS mode) cannot travel as it would normally go, and thereby potentially cause premature roller needle bearing failure. In my particular case, the 2 MDS lifters were saturated with oil, but the 2 non-MDS lifters were nearly dry. The only rational reason I could come up with for saturated MDS lifter roller failure is not lack of lubrication, but rather the lifter rotating off center due to faulty keeper design (made of plastic), or the internal part of the lifter is not fully locked, and thus causing a slight free-floating of the lifter during NON-MDS operation. This would result in banging of the roller, and hence damage, and over time, damage camshaft lobe. If the problem were (as some have suggested on here) faulty lifter design, then there would be lifters dropping out all over the place. While I do believe the lifters are partially to blame, the biggest problem is oil. Now here's the big secret I've been holding out on. I have already spoken to one engineer on this matter via telephone, from the Johnson company. And he has informed me that the biggest problem with the hemi engine is oil related. Not the type of oil, or frequency of change, but that some of the lifters were not getting enough oil. This led to Chrysler accusations against consumers for "idling the engine too long" since the oil pump reportedly doesn't put out enough volume and flow during high temps and low RPM. So Johnson has designed a non-oiled based lifter (if that's even possible) while also providing a higher grade lifter that requires oil. But this is what the engineer cautioned me when (or if) purchasing his lifters. And I quote, "make sure the lifters are getting oil because for some reason, some of the lifters are not getting oil, and that's what causing the rollers to fail". No matter how you guys look at it, there is a problem, small (per some on here who believe it to be a rare problem), and the problem must be worked. Fortunately, the Hemi might be coming to its end because neither GM nor Chrysler can satisfy the EPA's fuel efficiency standards. And the MDS and DOD (GM) failed to some extent. So now they appear to want to copy Ford with a twin turbo 6 cylinder...a wise move in my opinion. But that will by no means lead to me buying a future Chrysler product. I'm done with them...forever. My 99 Suburban has done me quite well, having paid more than enough for her service and still going. But my next new truck will likely be a Toyota Tundra, or possibly a Ford ECO-Boost. Back log on standard Hemi lifters as well as the Hellcat lifters. So I'm likely just going to bite the bullet, try to find a used Hemi engine, install it, and dump that blasted thing and cut my losses. I look forward to Chrysler's eventual collapse and bankruptcy. Hopefully Trump stays in office so he can prevent another bail-out for such a failed industry. Joe
 
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NO the lock pin does not have to line up with the oil hole...it locks on the circumferential ledge that's machined into the outer body...that also forms a gallery, so the lock pin can be any angle away from the oil hols and still function
 
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Originally Posted by Shannow
NO the lock pin does not have to line up with the oil hole...it locks on the circumferential ledge that's machined into the outer body...that also forms a gallery, so the lock pin can be any angle away from the oil hols and still function
Interesting. So then, why would the hole even need to be there?
 
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Originally Posted by Shannow
Originally Posted by JosephA
I disagree. And if I am wrong, then prove it. If the poppet is stuck open, and the solenoid is closed, the lifter still needs lubrication despite the fact that it's not doing much work. Are you assuming that the lifter in MDS mode does not get oil, and that oil only comes from the MDS solenoid? One thing that helps with troubleshooting is understanding the total process of the operation. So I'd like you to explain the entire process of the lubrication of the MDS lifter. Does the solenoid play a factor in lubricating MDS lifters? Or is it soley for pushing in the lock pin so that the internals can free-float via the spring? And if the solenoid does not lubricate the lifter, then the lifter must be getting normal lubrication the same as the non-MDS lifter. And if/since the MDS lifter while in locked mode (solid state) is operating to full capacity, how then is the lifter lubricated? From the bottom up or the top down? I'm trying to get you to understand is oil in a normal valve train travels from the block to the tiny little holes on the side of the lifter. As the lifter slides up and down (say my 5.7 Vortec), oil travels inside of the lifter upward, through the pushrods, and out of the tip of the rod and falls back into the head lubricating also the springs and rockers, where it then falls back into the oil pan. Please explain the entire lubrication process. THEN I think you will see more clearly my point. Joe
The lifters are all lubricated and the hydraulic lash adjuster component functions the same for both the regular and the MDS lifter. The additional gallery that feeds the MDS pins applies oil to the circumferential gallery inside the lifter outer body, and pushes the pins in causing the traditional lash adjuster component to float in the outer body and not transfer motion to the rockers. It's really VERY simple...and the MDS solenoid does not constitute a leak...
I may have been misunderstood. I never claimed the solenoid itself causes the leak. I have suggested that the solenoid supplies oil pressure to unlock the MDS lifter by pushing in the lock pin and unlocking the lifter. But here's my question. Once the lifter is unlocked, how is it left unlocked during economy mode? As the internal springs bob and and down (it has to since the roller is still riding the cam lobe), what is keeping the lock pin from locking during economy mode? That is something I've yet to get answers from on here. I understood this to be the direct cause of oil pressure from the Solenoid. The video image seems to show oil pressure applied to the MDS lifter while in economy mode, which prevents the lock pin from locking as the internals reach maximum height. But when the lifter must become solid again (non-MDS mode), the solenoid cuts off oil pressure and that permits the lock pin to re-engage and lock the lifter. Is this correct? If not, please correct me. Joe
 
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If the lock pin does not lock, that lifter remains in MDS operation, which would be noticeable. Everything else would operate normally. And I've provided numerous examples that show lifter failure happens on non-MDS engines, you claiming that it doesn't at this juncture is utterly ridiculous.
The proof I look for is actually witnessing it, or speaking to someone who has experienced. There is not enough reports of non-MDS engines losing lifters and camshafts. The 2000-2005 Hemi's (to the best of my knowledge) did not suffer lifter and camshaft failures. They instead had valve seat issues. It wasn't until the MDS system came about that lifters began crashing. Keep it simple guys. I know what many of you are trying to do. You want to create doubt and squash any idea that MDS is a problem. Here's the simple approach. Did Hemi's lose lifters and cams prior to MDS? No they did not. Did GM's lose lifters and cams prior to MDS? No they did not. Did both start losing lifters and cams after DOD or MDS? Obviously yes. We do not have to agree the cause of the problem. But ignoring it is not the answer either. And that seems to be what some on here are doing...ignoring the problem, acting as though it doesn't matter, and telling the victims that they are just out of luck. And the reason why I know you guys are wrong is because I've seen this personally 3 times before...on a 1997 Dodge Stratus 2.4, a 2002 Dodge Stratus 2.7, and now a 2012 Dodge Ram. In all three vehicles, they all failed catastrophically before hitting 120,000 miles AFTER routine maintenance and repairs performed by Chrysler. And what was I told by Chrysler? "It's rare that this happens, and we are sorry". Well guys...that excuse won't work anymore. Thankfully, the Internet has helped a lot of people out there and that explains why Chrysler is struggling financially, and they should. Many of my friends are all saying the same thing, "we are not buying domestic anymore" since the "top three" don't seem to care about the quality they put out, as long as their bank accounts continue to overflow with money. Don't get me wrong. I love the Dodge Ram truck. But I'm wishing I would have bought the older one with the 5.9 instead of the Hemi. At least that engine (while having had some problems) never lost lifters and camshaft as such an early state. Joe
 
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And the main fact you all are purposefully ignoring is this. Since some of you claim that the failed lifters are rare, you still have not explained why both Chrysler service departments and private customers are on hold for lifters, and up to 3 months? Why is their a large demand for such a short supply? You all already know the answer to this, but you are ignoring it....as expected of course. At least the engineers and mechanics I've spoken to are honest. And some of you on here are honest. But some of you are obvious schills simply trying to protect Chrysler. Joe
 
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1. The above again assumes there is an oil black hole that results in pressure loss. This is not the case as I've explained. 2. Once something happens, whether it is the driver hitting the pedal or encountering a grade to increase load, the solenoid has the power removed from it, which ceases the pressure being applied to the MDS orifices, which then allows the springs behind the lock pins to push the pins back into their grooves, making the lifters single units again. The solenoid does not, in any part of this, "remain open" when MDS is called to be deactivated. It is the cessation of oil pressure caused by the solenoid being deactivated that allows the pin to seat, thus disabling MDS.
Bingo! THIS is what I was looking for. So then, we agree that the solenoid cuts oil pressure by the ECM to engage (lock) the lifter. So then, oil pressure is sustained to the MDS lifter during economy mode. Now taking the solenoid completely out of the picture here, if the solenoid is off during activation, and the lifter is solid again (locked), this means that the lifter receives its lubrication "normally" through the valve-train galley as the other lifters do. Correct me if I'm wrong please.... That being the case, what happens to the normal oil flow if the lock-pin hole is left open during "locked" operation? You already know what my theory suggests....but for the record, I did not come up with this myself.....This came from an automotive engineer. Joe
 
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Originally Posted by JosephA
That being the case, what happens to the normal oil flow if the lock-pin hole is left open during "locked" operation? You already know what my theory suggests....but for the record, I did not come up with this myself.....This came from an automotive engineer. Joe
Nothing. The passages for the conventional oiling don't overlap with the MDS cavity as can be viewed in both cutaway diagrams I posted.
 
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Originally Posted by JosephA
Originally Posted by Shannow
NO the lock pin does not have to line up with the oil hole...it locks on the circumferential ledge that's machined into the outer body...that also forms a gallery, so the lock pin can be any angle away from the oil hols and still function
Interesting. So then, why would the hole even need to be there?
To feed the gallery that supplies the oil to press the lock pins in... And yes, the MDS solenoids must maintain that oil pressure to keep the cylinders deactivated.
 
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The cutaway of the lifter had me scratching my head for a while, so I pondered it as I mowed (where I do my best engineering)... Then it hit me, the hydraulic lash adjuster NRV is upside down, indicating flow from above downward...and in order for the lock pins to unlock there's a cavity behind it with no pressure. A little googling, and YES, the hydraulic lash adjusting mechanism is fed from the pushrod. The regular lifters have the lash adjuster supplied in the regular location...however the lifter body and rollers are lubricated exactly the same way, from the same gallery...can see both details on the second pic lifted from a youtube vid...same gallery and relief for body/roller oiling...just the drilling for the lash adjuster on the non MDS lifter. So - Body is lubed like the others. Roller is lubed like the others The lash adjuster is fed from the pushrod end on MDS lifters, body end on non MDS lifters.

MDS lifter.jpg


Lifters two.jpg
 
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