Best explanation I've seen so far for Hemi cam/lifter failures

New Hemi Engine Swaps

  1. MopaR&D

    MopaR&D Nerd Member

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    I stumbled across this video and after watching it I think this guy has come as close to identifying the issue (and fix) as anyone. He worked as a Dodge/Chrysler/Jeep tech for years so he has tons of experience with these engines. He did mention Uncle Tony's video (without any name-dropping) and says his theory *might* have some validity but not as much as his idea. In a nutshell he claims that because the MDS works by sending oil pressure to the lifter bores to "unlock" the MDS lifters, it's when the MDS mode is NOT engaged that the lifters get insufficient oil. And putting in the MDS delete plugs actually fixes the issue because they leave the MDS passages open allowing constant oil flow to the lifter bores.

    He goes a little long with the intro, doesn't start getting into the "meat" of things until about 11:00

     
    Last edited: Jan 17, 2021
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    • Cuda416

      Cuda416 FABO Gold Member FABO Gold Member

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      i'm told by my eldest who works at a dealership, the ones he's seen fail tend to fail in one of two ways.

      1. The internal pin/lock that's part of the MDS function, gets out of alignment causing the lifter to turn into a solid lifter basically.
      2. When the MDS turns off, the oil slammed into the lifter and it pressurizes extremely fast. The explaination he was given is that it slams into the cam pretty hard and causes the roller pins in the lifter to fail consequently causing the cam to fail.

      i have NO way to validate these, but they make sense to me.
       
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      • 408 swinger

        408 swinger FABO Gold Member FABO Gold Member

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        I haven't watched the video yet. I'm not taking anything away from anyone in thier explanations. I have seen with my own eyes NON-mds lifters fail, too. Everyone is so hung up on the MDS being the issue. It might be for the MDS lifters that fail, but, what about the NON-mds lifters that fail? This has been discussed ten ways from Sunday. I wish someone had a 100 percent explanation. I have theories that seem to get dismissed.
         
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        • Cuda416

          Cuda416 FABO Gold Member FABO Gold Member

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          Yup, totally agree. I should have made it more clear I was thinking about the 6.1 and up. Lots of folks point out how they "never" fail because of billet cams etc. 5.7's fail apparently due to crap material is the casting.

          I'm sure there's a little bit of truth in all of it.
           
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          • 408 swinger

            408 swinger FABO Gold Member FABO Gold Member

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            I was under the impression that the 6.4 stuff didn't fail either. Lately, I've seen some for sale with bad cams. On that note, those seem to be MDS engines. They don't say which lifters had failed, though. In a previous thread about this, I had posted a pic of an Eagle 5.7 cam lobe. That lobe was a non-mds lobe. I'm starting to think that maybe with my "bad metal" theroy, combined with Uncle Tony's theroy, could maybe explain?
             
          • Cuda416

            Cuda416 FABO Gold Member FABO Gold Member

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            I dunno much honestly, only what I'm told/shown. I tend to believe it's a combination of low rpm operation (idling) and either crap cams in the 5.7's and MDS in 6.1 and above. What I CAN say, is I have a 6.1 and a 6.4 in my garage. The 6.1 mileage us unknown and the 6.4 is a 2018 with 18k on it. Both have spun rod bearings. I haven't torn into the 6.4 it to check the lifters yet but at this point it would be impossible for me to determine which happened first if there's a failed lifter/lobe.
             
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            • KosmicKuda

              KosmicKuda FABO Gold Member FABO Gold Member

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              It may not be a single item that causes failures. I tend to think it may be a combination of things.
              Uncle Tony's theory may be a contributor for engines that see a lot of idling. When Chrysler asked Tom Hoover father of the Hemi) for design input he suggested raising the cam in the block. That's a design feature that will NEVER change.
              MDS flaw thories are interesting. Larry Shepherd says in his Hemi book that there is no need to replace those lifters when disabling MDS, just run them as is. I do not have a high opinion of Shepherd after reading his stuff for a few decades.
              FCA, or whatever the company is called these days, has never publicly admitted any fault. If they did, it would open up a huge monetary obligation. But, they have standardized on the heavy duty "Hellcat" replacement lifter across the board.

              Whatever! I'm not deterred and going ahead with my 12,000 mile Eagle 5.7 swap. I have MDS plugs and 16 new factory Hellcat lifters to swap in. Good oil and filters and I'm hitting the road.

              *****
              EDIT: I wrote the above based on my 47 yrs of engineering, design and manufacturing experience. I just watched his video and the first half pretty much agrees with what i said. The G3 is not perfect but so what. Just fix it when it breaks.
               
              Last edited: Jan 18, 2021
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              • MopaR&D

                MopaR&D Nerd Member

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                Guys you're getting ahead of yourselves lol just watch the video. @408 swinger he explains in the video that the oil passages from each solenoid go to both the MDS and non-MDS lifters in that set since each solenoid goes to a set of 4 lifters and the MDS cylinders are staggered. It could very well be that the non-MDS lifters are also failing because they are also not getting oil when the MDS is deactivated.

                And again, the guy in the video reiterates it very well is most likely a combination of factors. He does NOT claim to have the "final answer" more just another perspective on the issue and some new ideas to consider.
                 
              • RustyRatRod

                RustyRatRod I didn't do it. FABO Gold Member

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                IMO, it all stems from people trying to let technology do too much. That's my opinion and I'm stickin to it.
                 
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                • 408 swinger

                  408 swinger FABO Gold Member FABO Gold Member

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                  I did watch the video. He has some valid points. I too, as mentioned earlier, think it's a combination of things that lead to failure. In the end, Mopar left us to just deal with it. Sometimes I wonder why I'm so loyal to the brand?
                   
                • DionR

                  DionR Well-Known Member

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                  I wonder if he knows that the 6M cars don't have MDS. One more reason to buy a manual car, in my mind.

                  :lol:

                  I have an additional theory, not a competing or different one, but something that might contribute to the lifter issue.

                  Everyone has heard of the "hemi tick". My 2015 R/T 6M ended up getting new lifters and pushrods on one side of the motor due to an excessive tick. I think when the pushrods are manufactured, they sometimes end up being a little short, causing clearance between the pushrod and lifter resulting in a "tick". The check per the STAR case was to pull the pushrods and check for bent ones, and if found replace all the pushrods and lifters on that side, and all for free because it was under warranty. Now, I don't believe that I bent the pushrods by over-revving the motor, so why were they bent? I think they were made that way and it is a manufacturing issue.

                  To flesh out the "manufacturing issue" idea, let me share a past experience. Years and years ago I ordered the MP conversion pushrods to put Magnum heads on an LA block. When they came, I opened the package and noticed that one pushrod was bent. So I rolled all of them on my desk and found 4 bent pushrods in total. These were new in the box, direct from MP. So, called the place I ordered them from and they sent me another box of 16 pushrods. Don't remember how many of those were bent, but some were. I ended up with a full set of straight pushrods between the two boxes (that I never ended up using :BangHead:) and went on my way. Remember, both of these boxes were brand new.

                  I think it was the method of manufacturing that caused the pushrods to be bent when new. They are just a tube cut to length with ball ends pressed in. So what happens if the process says "press ends in until they are fully seated" but you start with an end that is slightly off square or for some other reason it takes a bunch more force to press in than it should? Could it maybe bow or "s" curve the pushrod? I think it can, and does, resulting in a pushrod that is below spec for length.

                  Any guesses how the OEM G3 Hemi pushrods are manufactured? Yep, tube cut to length with ends pressed in.

                  How does that relate to the lifter issue? Well, I'm not going to say I have enough experience to say for sure, but to me it seems reasonable that too much gap on the pushrod means it could be hammering on the lifter which could cause the rollers in the lifter to fail. Hey, wait...the guy in the video said the same thing when talking about the 3 springs under the MDS valve in the lifter. :D

                  If so, this would mean that both 6M and 8A cars could have issues. It also means that non-MDS lifters in an MDS motor that isn't seeing enough oil on the lifters could fail.

                  The fix? Buy a 6M car that doesn't have MDS and swap out the OEM pushrods for a quality set of aftermarket ones; then off you go with a quieter Hemi that will last longer.

                  Just some thoughts.
                   
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                  • AJ/FormS

                    AJ/FormS 68 B'cuda fb, Form S clone ... 367/A833/3.55s

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                    I have no idea about this subject matter, but I like your way of thinking
                     
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                    • my5thmopar

                      my5thmopar Life Long MOPAR Owner FABO Gold Member

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                      I didn’t watch the video but, asked a service mgr at the dealership today what he thought about it. I was discussing my 2019 Ram with 5.7. He says they see it at 20k or 150k miles or not at all with nothing consistent. He says change your oil regularly. That’s what you can do to minimize the chance. He says it’s bad metal in the pin for the roller. Nothing official though.
                       
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                      • MopaR&D

                        MopaR&D Nerd Member

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                        Agree on the manual trans and pushrod theory, I have a 2014 5.7L from a Ram 1500 with 137k miles and bad cam lobe/lifter that was replaced under warranty. When removing the rockers it felt like the lifters had barely any preload, certainly less than what I'm used to on a LA/Magnum. I intend to put a factory replacement 6.4L SRT MT cam in it and MDS delete with all new Hylift-Johnson non-MDS lifters, probably also hardened pushrods that are slightly longer (.010-.020") than stock and upgraded valve springs. That project is a ways off for now though my Duster runs awesome with the 5.9L Magnum and I need to save up for all the swap parts... may go for another car/truck to swap it in lol I dunno
                         
                      • MopaR&D

                        MopaR&D Nerd Member

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                        Ok fair enough. I do partly agree it's always shitty when a company decides to screw over the customer like that because it's cheaper. Myself I'm only "loyal" mostly to classic Mopars just in the sense they're my favorite type of car to mess with but when it comes to late models I don't think I'd buy a "Chrysler" product unless it was a truck. Everything that comes with the G3 Hemi and is supposed to be fast weighs at least 4400 lbs.

                        To be honest my next car to use as a daily driver is most likely going to be a 2004-2008 Acura TL. They hold up amazingly well and run forever with excellent fit and finish, can't say that for most (Daimler)Chrysler products of the same years.
                         
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                        • RustyRatRod

                          RustyRatRod I didn't do it. FABO Gold Member

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                          Mopar left all of us when Daimler bought them out. Actually, some before that.

                          My fix for it is snatchin that Gen3 POS out and throwin it in the ditch.
                           
                        • turbofreek

                          turbofreek batcrap crazy racing team

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                          short travel lifters, better pushrods and billet cam core. all good but the oil pump of a stock 5.7 isnt gonna be pusbing the oil needed for the non mds lifters setups. why many lose aftermarket cams in baic 5.7 or 6.4 vvt engines...my theory anyways.
                          my stroked 6.4 idles rather quiet compared to wifes daytona for a 650+hp engine before boost. yet i have high flow/presure hc pump, billet cam.core, the short travel hd aftermarket lifters, locked out vvt, etc..
                           
                        • MopaR&D

                          MopaR&D Nerd Member

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                          What about factory manual-trans setups with the MDS already deleted? They have non-MDS lifters... and wouldn't an oil volume issue (if the pump is too small) show up as lower-than-normal pressure at lower RPMs?
                           
                        • turbofreek

                          turbofreek batcrap crazy racing team

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                          i think its accelerated wear at idle. add on vescocity breakdown from the very very light weight oil used and extended life cycles people puy it through isnt helping. lots of 5k and even 10k oil chage intervels being ignored. leads to premature failures.
                           
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                          • MopaR&D

                            MopaR&D Nerd Member

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                            That makes sense. I've never been a big believer in the extended oil changes for modern cars, I do my mom's 2014 Chrysler 300 V-6 every 5k miles but even that feels like it's pushing it just a tad. I always use full synthetic in her car for that reason.

                            Almost makes me want to get a good-quality low-mileage or stock rebuilt 5.7, fill the sump with ATF (doesn't lubricate as well as motor oil) and start it and let it idle for hours on end. Then maybe after 100 hours or so if nothing has failed yet pull apart the valvetrain and inspect the cam and lifters...
                             
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