For the guys who think deactivating the mds via a tune is a good idea

[mikeru]

I think that leads right back to poor quality cam cores and not enough spring pressure more then anything Mike.I don't really think it's the lifters per say,as it is the cams start to delaminate,and then the lifter wheels start to skid on the lobes.
It's a tough call on the mds system,but there are no solenoids and screens in any of the hellcats,or the 6 speed Challengers,and they still have cam issues as you stated,although the 5.7 stick cars,do appear to have less cam issues then the automatic 5.7's with mds have,but that's just going by whats posted,as we'll probably never get access to Chryslers records.The stick 6.4 cars seem to have more issues then the stick 5.7 cars,and they use a differant cam then the 5.7's use,which leads me back to poor quality cams then anything.It's not unheard to hear of non-mds 6.4's having cam issues,but the non-mds 5.7's don't show up near as often as the 6.4's do. I do know that there's not as many failures after you install a good aftermarket cam,and the new style lifters,and upgraded valve springs.

I think you're absolutely right about this. Too many people see cams worn down to the nub and lifters with damaged bearings and think the lifter took out the cam. I was one of them as well. The photos that @Black1500Ram posted are pretty convincing for me. The cam has had it but the lifters still look pretty good in comparison. An aftermarket cam and MDS delete could be in my future if we end up keeping this truck for the long term.

 

[Black1500Ram]

I think that leads right back to poor quality cam cores and not enough spring pressure more then anything Mike.I don't really think it's the lifters per say,as it is the cams start to delaminate,and then the lifter wheels start to skid on the lobes.
It's a tough call on the mds system,but there are no solenoids and screens in any of the hellcats,or the 6 speed Challengers,and they still have cam issues as you stated,although the 5.7 stick cars,do appear to have less cam issues then the automatic 5.7's with mds have,but that's just going by whats posted,as we'll probably never get access to Chryslers records.The stick 6.4 cars seem to have more issues then the stick 5.7 cars,and they use a differant cam then the 5.7's use,which leads me back to poor quality cams then anything.It's not unheard to hear of non-mds 6.4's having cam issues,but the non-mds 5.7's don't show up near as often as the 6.4's do. I do know that there's not as many failures after you install a good aftermarket cam,and the new style lifters,and upgraded valve springs.

I'd agree with this. Part of my hypothesis is that I don't believe it to be a MDS correlated issue at all.

From examining my personal cam and lifters, as well as doing a great deal of academic / engineering researching on topics such as Hertzian stress, axial load (makes sense why my pin was walking out), needle bearing load and stress, lubrication and fatigue analysis, my hypothesis is poor metallurgy of the cam.

I've seen clear failures of the metal surface on several cam lobes in several engines, with no discernable failure of the corresponding lifters. Usually there is one cam lobe and corresponding lifter that have the worst damage (pics in my other thread).

Here's an academic paper on Skidding Analysis of Exhaust Cam-Roller Unit in the Steady/Startup Operation of Internal Combustion Engine for anyone that's interested.
A quote from the conclusion

"Appropriately reducing the oil viscosity or increasing the initial load can effectively reduce skidding. In addition, the effect is more pronounced during the steady running process than the startup running process."

This leads me to put more weight on the light valve spring load hypothesis as well. My pics in Post 142 show the skidding wear on the base of the cam profile, while the spalling is on the lift section of the cam prifile, where the load and stress is increased and substrate metallurigcal properties have failed.

None of this is conclusive; more investigation is certainly needed.

 

[EriikK]

Towing with the 66rfe I would be more worried about the transmission then fuel savings and or cam lifter failure.

Yeah I hear you. The previous owner of my truck apparently put in a heavy duty rebuild of the 6-speed so maybe I will dodge the bullet on trans problems. If it's shifting a lot I generally put it in T/H. I don't know exactly what rebuild it is, probably a mid-priced one for towing. The case is painted black and the torque converter looks quite different than stock.

 

[HEMIMANN]

Keep in mind there have been a number of failure pictures on here showing rollers that not only skidded but turned in their bores to wipe out cams.

That's not due to a soft cam.

 

[Wild one]

Keep in mind there have been a number of failure pictures on here showing rollers that not only skidded but turned in their bores to wipe out cams.

That's not due to a soft cam.

Usually the lobe is pretty well wore down, by the time the edges of the groove that's wore into the lobe ,catch the edge of the lifter and spin it sideways,and that kind of leads back to a soft cam core.

 

[Black1500Ram]

Keep in mind there have been a number of failure pictures on here showing rollers that not only skidded but turned in their bores to wipe out cams.

That's not due to a soft cam.

I did see that and still believe it has to do with the cam… and the plastic yokes.

If I swap out my MDS lifters, I’ll definitely be getting billet yokes.

 

[HEMIMANN]

I did see that and still believe it has to do with the cam… and the plastic yokes.

If I swap out my MDS lifters, I’ll definitely be getting billet yokes.

I swapped plastic yokes for billet on my Harley when upgraded cam. Plastics have no endurance fatigue limit and age harden. But - they're cheap! Even the more expensive composites, compared to billet metal.
Thr lifter guides in the bike looked like polypheneylenesulfide PPS, which is about as good a plastic as there is, but still.

 

[DeckArtist]

I did this up until my second valve spring broke. Heard it was a good way to avoid the dreaded lifter/cam issue. Found out the hard way it wasn't good after all. I am at 139k right now and have been trouble free since the 56k mark. The drone is non-existent for the most part.

There is extremely little lag time when going from eco mode to full throttle. Mine doesn't stumble or lag but then I have a heavy right foot

 

[ramffml]

I did this up until my second valve spring broke. Heard it was a good way to avoid the dreaded lifter/cam issue. Found out the hard way it wasn't good after all. I am at 139k right now and have been trouble free since the 56k mark. The drone is non-existent for the most part.

There is extremely little lag time when going from eco mode to full throttle. Mine doesn't stumble or lag but then I have a heavy right foot

I'm not sure what you're saying, you turned off MDS until your second valve spring broke?

But what about 95% of lifter/valve spring failures which occur on guys who just get in and drive? This forum is not representative of how these hemis are failing, most people are keeping MDS enabled and still getting failures.

 

[04fxdwgi]

I did see that and still believe it has to do with the cam… and the plastic yokes.

If I swap out my MDS lifters, I’ll definitely be getting billet yokes.

I like these statements on the bottom of their page:

"If you are not qualified to be inside an engine and don't understand things such as that mds lifters are absolutely not the same dimensions as non-mds lifters, please do not purchase these parts. Thank you,

Also, if you are building a stock 5.7 truck motor on a stock cam and stock lifters, all reused-used parts. For god's sake, please leave this page."

 

[markabby]

if turning off the MDS is such a bad idea, then why is that option on the steering wheel? You'd think they would not program that into the truck if they knew it would cause problems.

I still turn it off now and then. Just too many pros and cons to this, and, not only in this forum, but numerous others have the same "for or against" arguments.

 

[Lsujker]

if turning off the MDS is such a bad idea, then why is that option on the steering wheel? You'd think they would not program that into the truck if they knew it would cause problems.

(American) Car manufactures do NOT want you driving the same vehicle for 10 years plus. They want your money right now and later.

There is a conspiracy theory vehicles are built to a "point". Probably some truth to that.

 

[ramffml]

(American) Car manufactures do NOT want you driving the same vehicle for 10 years plus. They want your money right now and later.

There is a conspiracy theory vehicles are built to a "point". Probably some truth to that.

I don't think there is any conspiracy here. All engineering is a compromise, and setting targets for the lifetime of a product is not only normal and expected, there is literally no way to avoid it.

The question is, how long does Ram intend the truck to last?

I refuse to accept that MDS is some sort of conspiracy to reduce the lifetime of the engine. That's way too far out in left field for me. In fact, I see the opposite. Ram has made constant improvements to the quality of the trucks, with these 5th gens being best to date. The transmissions have gotten more reliable as well. No brand wants the weight of "poor quality" hanging around their neck.

 

[Docwagon1776]

(American) Car manufactures do NOT want you driving the same vehicle for 10 years plus. They want your money right now and later.

There is a conspiracy theory vehicles are built to a "point". Probably some truth to that.

Everything is engineered with an expected useful life span. That's not the same as engineered to break at "X" point, but a realization everything breaks at some point no matter what, and that other criteria matter as well.

Of course makers want you buying vehicles, but the number of people buying a *new* car because their current vehicle broke beyond economical repair is miniscule. Those people are buying used cars with few exceptions, especially high profit models. New car buyers trend older and more affluent and are buying the new vehicle because they are bored with their old one, they want a new gadget or gizmo the newer model comes with, etc.

It'd be a lot easier on makers if the car just exploded at X miles and you replaced it like you do dish soap, but that's not the reality of car buying. Hence we get stuff like horsepower wars, bigger screens/more screens, gadgetry like under frame cameras for off roading, etc. as well as all the 'life style' marketing.

 

[markabby]

(American) Car manufactures do NOT want you driving the same vehicle for 10 years plus. They want your money right now and later.

There is a conspiracy theory vehicles are built to a "point". Probably some truth to that.

on the same token, not every Honda, Hyandai, or Toyota runs for 200,000 miles, you only hear of the exceptions doing that. They break down just as much as any other car/truck.

For me, when i lived up north in NYS, it was the salt that ruined any vehicle in a few short years. Now, adding tons of salt each year would make for a better conspiracy theory...lol

 

[Wild one]

I see the opposite. Ram has made constant improvements to the quality of the trucks, with these 5th gens being best to date. The transmissions have gotten more reliable as well. No brand wants the weight of "poor quality" hanging around their neck.

I don't know if i'd agree with "constant improvements" to their longevity,i don't think 0W-20 was an improvement geared towards more longevity,lol
The trucks are geared towards generating profits and not p'ing off the gubberment nannies,not p'ing off the consumer falls well below those 2,lol

 

[mikeru]

The trucks are geared towards generating profits and not p'ing off the gubberment nannies,not p'ing off the consumer falls well below those 2,lol

That's because there are not really any car companies that are known for great customer support or caring about what the customer wants. If there was you can be sure that "not p'ing off the consumer" would move up that list for the other car companies.

 

[Lsujker]

Of course makers want you buying vehicles, but the number of people buying a *new* car because their current vehicle broke beyond economical repair is miniscule. Those people are buying used cars with few exceptions, especially high profit models. New car buyers trend older and more affluent and are buying the new vehicle because they are bored with their old one, they want a new gadget or gizmo the newer model comes with, etc.

I thought about this as well. My comment was short sided. Just thinking, how long does an average new car buyer keep it? Lets say 7 years. The original owner would never know if the lifespan was 10 years. Would think it's a great reliable car and buy again. Not everyone is as educated as you and others or even care to know.

Entire point of this thread is the MDS is not damaging the cam and potentially helping it. Known issue thats been around for some time. Why has ram not fixed it? Because they don't have to. It lasts just long enough.

Honda, Hyandai, or Toyota

LOL. like how you squeezed Hyandai in between those two. Different leagues. (wife has one... don't tell her i said that)

 

[Docwagon1776]

I thought about this as well. My comment was short sided. Just thinking, how long does an average new car buyer keep it? Lets say 7 years. The original owner would never know if the lifespan was 10 years. Would think it's a great reliable car and buy again. Not everyone is as educated as you and others or even care to know.

It depends on who's numbers you believe, manufacturers or marketing groups or who, but there's a pretty broad consensus that a strong majority (say, 2/3rds) of US car buyers swap vehicles within 5 years regardless of if they bought new or used. Nearly everyone swaps before 8 years, again independent of if bought new or used. New buyers swap sooner than used, but lease numbers probably skews that somewhat and whatever percentage of people buy their leases out would be counted as swapping cars in registration data since ownership transfers from the leasing company to the consumer at that point.

So, yeah. The people who care if a vehicle runs to 200k miles are probably 2-3 customers down the chain from what the manufacturer cares about. Dealers, now, they care because they make a big chunk of their profit from used car sales and the service center.

 

[Docwagon1776]

That's because there are not really any car companies that are known for great customer support or caring about what the customer wants. If there was you can be sure that "not p'ing off the consumer" would move up that list for the other car companies.

Isn't Porsche's reputation pretty strong in that arena? I know they aren't really a mainstream company, but the few folks I know who own them are generally pretty strong on the total ownership experience. Much more so than anyone else, anyway.

Of course, that's a game you pay to play. I looked at the Cayenne but ultimately decided I'd rather keep a sports car and a truck vs a performance SUV, especially at the money they want for them.