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

[04fxdwgi]

^^^ ++1
The complete "delete" (cam, lifters, oil galley solenoid delete plugs and tune and bump RPM to 750) is only way to do it completely. Replacing the solenoids with the plugs is a must, as far as I can see. That's how the manual xmission cars are for a reason.

I think the roller failures doesn't have anything to do with the MDS, just a lubrication scheme design for the cam / rollers could be improved.

But, until this engine dies or I hit the lottery and do a 6.4, I still have button options if I desire.

 

[Black1500Ram]

delete

 

[6speed4.7]

Is that the same as the 9-Drive I showed the link for?

The majority of the reviews for the 9-Drive on dot com read as though it's excellent.

For the cost, it seems to be worth a gamble. If it craps out and throws the truck into limp mode, that's not the end of the world.

Plus, many of the products on Amazon offer free returns for 60 days. Like a free testing period.

.

My 9-Drive has worked flawlessly for 3-4years
It’s on its 2nd truck
Has to be removed to install/uninstall a tune, learned that the hard way
Cost hardly anything Canadian- bought locally
Easily my most favourite mod, drive around winter/summer at max 3.9

 

[La Ramie]

Wouldn’t disabling the MDS solenoid i.e. inactive, which would means the oil galleries are open, unrestricted or blocked, be the same as installing the solenoid plug which would replace the solenoid and leave the oil galleries free and open??
Whereas, when the MDS is on and the solenoids are active, it would restrict the oil galleries and reduce the oil pressure to these 4 lifters to minimum just to keep them lubricated.

And yes, if anyone wants to ask, I saw the video. But I think the MDS system and solenoids are being understood and explained backwards.

 

[crackerjack1957]

Nope, not backwards
More pressure when MDS solenoids are open on deactivates lifters

Hemi Engine Tech - Multi Displacement System (MDS) · Help Center

 

[ramffml]

Wouldn’t disabling the MDS solenoid i.e. inactive, which would means the oil galleries are open, unrestricted or blocked, be the same as installing the solenoid plug which would replace the solenoid and leave the oil galleries free and open??
Whereas, when the MDS is on and the solenoids are active, it would restrict the oil galleries and reduce the oil pressure to these 4 lifters to minimum just to keep them lubricated.

And yes, if anyone wants to ask, I saw the video. But I think the MDS system and solenoids are being understood and explained backwards.

Increased oil pressure is used to collapse the internals of the lifter when mds is activated, causing it to stay closed.

 

[Racer9]

I'm no expert, and I didn't stay at a Holiday Inn Express, but seems to me I heard about some bad camshafts or lifters, that were installed. Something about the manufacturing process was not done properly. Also, the failure often happens on the non MDS lifters/cam, which to me rules out MDS as the problem.
Many people are saying "oil changes at proper intervals (or even sooner) with quality oil and limiting idling, will help longevity".

 

[4xdad]

Wow this is a lot of opinions. My personal experience is that I bought my 15 pw with the 6.4 new off the lot. I have 250k kms on my truck. I have always changed. my oil on time with pup 0-40 6 litres and half a litre of Lucas oil treatment. I shut off the mds at about 60k kms with a phazer tuner when I changed the tire size from 33-35s I only let my truck idle as long as I have to in the winter. No discernible tick yet

 

[Sherman Bird]

Nobody wants to read or research, just jump on the wagon of who's yelling loudest.

'Technology bad, me want dinosaur'

I dunno! When I watch videos of someone driving around in some ancient car touting the "good ole days", I do tend toward those simpler times, albeit briefly.

Then, thoughts of my own close calls in horrific accidents 40+ years ago, and my daughter's close call in 1999,
I am less maudlin about how " good" those cars were.

The progress of how cars have evolved to save us from ourselves has truly and remarkably improved these past few decades.

People love to gripe; that's just human nature. They tend to bemoan their current condition and go back to the past and pine for some emotion borne of nostalgia. I guess most aren't happy in the moment, and must view a dim future and pine for yesteryear. Just a thought.

One cute ad I see on TV has a family stuck in the 60's or 70's in technology and aren't going to contemplate anything new or modern. The ad has to do with electricity providers.

My luck with dinosaurs might just be that I'd be eaten or trampled by one! Who knows about that purple dinosaur, Dino?

 

[gears49]

So disabling MDS via the gear selector is bad ?
Not looking forward to listening to the drone, but would rather do that than damage my motor.

I have a 2018 2500 with the 6.4 which is used primarily as a tow vehicle. Tow/Haul mode will deactivate the MDS. Hmmmm......Probably a good thing I don't like to use the Tow/Haul mode. I get better fuel mileage without it.

 

[mikeru]

I have a 2018 2500 with the 6.4 which is used primarily as a tow vehicle. Tow/Haul mode will deactivate the MDS. Hmmmm......Probably a good thing I don't like to use the Tow/Haul mode. I get better fuel mileage without it.

I suspect your fuel economy is affected more when using tow/haul from the more aggressive shift points than MDS being deactivated.

 

[EriikK]

Yeah in my 2015 6.4 2500 tow haul mode basically means one gear lower all the time. It pretty much never goes into top (6th) gear. No wonder the fuel economy suffers. If tow haul mode changes the MDS, I can't tell. Frankly I was surprised at the graph of MDS coming on at higher speeds, I didn't know it does that. Driving on the freeway if MDS is coming on it's so subtle I can't detect it. So I'd let it do its thing.
Towing a 25' 6000 lb toyhauler , I use tow haul mode in town, it just feels happier. But out on the freeway I often turn it off and let it upshift. IDK if that's really good for the engine or not but lower RPM's seems like a good idea at least for economy.
Of course saving a few percent on fuel at the cost of a cam and lifter job would be a very bad decision. Any opinions here?

 

[Wild one]

Yeah in my 2015 6.4 2500 tow haul mode basically means one gear lower all the time. It pretty much never goes into top (6th) gear. No wonder the fuel economy suffers. If tow haul mode changes the MDS, I can't tell. Frankly I was surprised at the graph of MDS coming on at higher speeds, I didn't know it does that. Driving on the freeway if MDS is coming on it's so subtle I can't detect it. So I'd let it do its thing.
Towing a 25' 6000 lb toyhauler , I use tow haul mode in town, it just feels happier. But out on the freeway I often turn it off and let it upshift. IDK if that's really good for the engine or not but lower RPM's seems like a good idea at least for economy.
Of course saving a few percent on fuel at the cost of a cam and lifter job would be a very bad decision. Any opinions here?

Letting it go into mds mode like you're doing on the highway,is what you want,so you're doing things right. More oil is fed to the lifter bores when it's in 4 cylinder mode,when it's firing on all 8 cylinders is when the oil to the lifters is restricted

 

[White six four]

Yeah in my 2015 6.4 2500 tow haul mode basically means one gear lower all the time. It pretty much never goes into top (6th) gear. No wonder the fuel economy suffers. If tow haul mode changes the MDS, I can't tell. Frankly I was surprised at the graph of MDS coming on at higher speeds, I didn't know it does that. Driving on the freeway if MDS is coming on it's so subtle I can't detect it. So I'd let it do its thing.
Towing a 25' 6000 lb toyhauler , I use tow haul mode in town, it just feels happier. But out on the freeway I often turn it off and let it upshift. IDK if that's really good for the engine or not but lower RPM's seems like a good idea at least for economy.
Of course saving a few percent on fuel at the cost of a cam and lifter job would be a very bad decision. Any opinions here?

Towing with the 66rfe I would be more worried about the transmission then fuel savings and or cam lifter failure. If you're transmission is down shifting a lot I would either not let it go into 6th or just leave it in tow haul. These trans apparently don't like higher throttle downshifts. If you're not experiencing a lot of downshifting then disregard. I don't tow often with mine but I always manually downshift when I know the truck is going to need to anyways loaded or unloaded.

 

[ramffml]

Yeah in my 2015 6.4 2500 tow haul mode basically means one gear lower all the time. It pretty much never goes into top (6th) gear. No wonder the fuel economy suffers. If tow haul mode changes the MDS, I can't tell. Frankly I was surprised at the graph of MDS coming on at higher speeds, I didn't know it does that. Driving on the freeway if MDS is coming on it's so subtle I can't detect it. So I'd let it do its thing.
Towing a 25' 6000 lb toyhauler , I use tow haul mode in town, it just feels happier. But out on the freeway I often turn it off and let it upshift. IDK if that's really good for the engine or not but lower RPM's seems like a good idea at least for economy.
Of course saving a few percent on fuel at the cost of a cam and lifter job would be a very bad decision. Any opinions here?

With your transmission I'd be giving it every chance it has and using TH 100% of the time when towing. I don't know too much about your 6 speed but I know other transmissions make changes to the line pressure for the clutches etc.

And as for as lifter failure goes, well higher rpms means more oil from the crank. I think it's a win win to use TH when towing. Just my pair of pennies.

 

[mikeru]

Letting it go into mds mode like you're doing on the highway,is what you want,so you're doing things right. More oil is fed to the lifter bores when it's in 4 cylinder mode,when it's firing on all 8 cylinders is when the oil to the lifters is restricted

I would agree with the first part that more oil goes to the lifter bores while MDS is active, but I think it'd be more accurate to say that oil flow to the lifter bores goes to normal when it's firing on all 8 cylinders, not that it's restricted. Subtle difference maybe, but to say it's restricted may cause some people to conclude that oil flow to the lifter bores is less than they were designed to receive.

 

[Wild one]

I would agree with the first part that more oil goes to the lifter bores while MDS is active, but I think it'd be more accurate to say that oil flow to the lifter bores goes to normal when it's firing on all 8 cylinders, not that it's restricted. Subtle difference maybe, but to say it's restricted may cause some people to conclude that oil flow to the lifter bores is less than they were designed to receive.

I don't think i'd agree with the "normal" oil flow,lol. The plugs open up the oil flow,on the factory non-mds engines,there is no solenoid or screen to restrict flow with the non-mds plugs Mike. Which would lead me to think full flow is the "normal",not the other way around. The solenoids when closed ,like they are when all 8 cylinders are working is when oil is restricted,and pressure in the lifter bores takes a drastic drop

 

[mikeru]

I don't think i'd agree with the "normal" oil flow,lol. The plugs open up the oil flow,on the factory non-mds engines,there is no solenoid or screen to restrict flow with the non-mds plugs Mike. Which would lead me to think full flow is the "normal",not the other way around. The solenoids when closed ,like they are when all 8 cylinders are working is when oil is restricted,and pressure in the lifter bores takes a drastic drop

And that is the crux of the this discussion for me Rick. What is normal oil flow for the Hemi? I don't know the answer to that. But I would like to think the engineers who designed this engine would have taken oil requirements into consideration, both with and without MDS active. You always design for worst case normal operation.

My argument in this thread has been all along that the oil flow that's seen during 8 cylinder operation is sufficient. Otherwise we'd be seeing a heck of a lot more engine failures. I would argue that "normal" oil flow is what the lifter bores see when MDS is inactive. If the cause of the lifter/cam failures on Hemi engines is caused by MDS solenoids being closed, why are there lifter/cam failures on non MDS Hemi engines which utilize the plugs?

 

[Wild one]

And that is the crux of the this discussion for me Rick. What is normal oil flow for the Hemi? I don't know the answer to that. But I would like to think the engineers who designed this engine would have taken oil requirements into consideration, both with and without MDS active. You always design for worst case normal operation.

My argument in this thread has been all along that the oil flow that's seen during 8 cylinder operation is sufficient. Otherwise we'd be seeing a heck of a lot more engine failures. I would argue that "normal" oil flow is what the lifter bores see when MDS is inactive. If the cause of the lifter/cam failures on Hemi engines is caused by MDS solenoids being closed, why are there lifter/cam failures on non MDS Hemi engines which utilize the plugs?

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.

 

[Sillygoose]

My argument in this thread has been all along that the oil flow that's seen during 8 cylinder operation is sufficient. Otherwise we'd be seeing a heck of a lot more engine failures. I would argue that "normal" oil flow is what the lifter bores see when MDS is inactive. If the cause of the lifter/cam failures on Hemi engines is caused by MDS solenoids being closed, why are there lifter/cam failures on non MDS Hemi engines which utilize the plugs?

this.