MDS hemi lifters

[raven3]

Would there be any interest in discussing the design features and operation of the Hemi MDS lifter?

Seems like folks complain about their noisy hemi.

Believe the noise stems from the lifters.

There are several engine cut a way views of the lifter & engine location, posted by Chrysler.

Understand the oil is supplied from the rockers and oil flow is from the rocker through the lifter to the camshaft lobe
with a hole in the push rod.

The oil supply to activate the lifter release pin and disable the lifter must be from the side of the lifter ,
since the pin access hole is located in the side of the lifter body.

Noticed the head of the pin and the oil supply hole in the lifter body are slightly off set, to capture the compression spring loaded pin.

 

[R.L.K.]

Subscribed !

 

[R.L.K.]

I'm posting a short and poor video of my ECO Light . What I'm doing in the video is : ECO lt. On , then I shift down a gear ECO immediately goes off . Shift back up via button on column and ECO comes back immediately.
ECO still on , turn on tow/hall ECO goes out immediately, turn off tow/hall ECO comes on immediately.

I've heard downshifting one time and tow/hall will turn off the MDS , looks like the ECO indication on dash is directly related to MDS aka 4 cylinders only mode .
I've heard the two systems are separate but the parameters are very close to initiate each ?

What say you MDS experts and motor heads ?



https://vimeo.com/150112412

Thanks for any response .

 

[raven3]

Understand the MDS can be turned off with a programmer.
Like to learn more about this programmer.

First year for MDS in RAM was 2006 and automatically shut off at 65 mph.
2009 MDS shuts off automatically at 70 mph.

If the internal plunger in the lifter gets jamed from sludge, small solid particular, varnish, combustion soot, the partially extended plunger will leave the corresponding valve in a partially opened position and burn the valve, if it is the exhaust valve and or if intake valve, the flow rate will be reduced.

According to info on the PP oil bottle, average USA mileage is 13,476 miles\year...that's 10 years with 134,760 average miles on a 2006 hemi.
Power train was warranted for 100,000 miles.
Has therebeen any recalls or TSBs on the lifters or MDS?

 

[GoldDot]

There is alot of info in the jeep forums on the hemi tick.

Cant find the thread but one guy took his lifters out and on a few that pin on the side was not aligned with the hole correctly.

 

[raven3]

Golddot,
Believe the pin center line is supposed to be off set from the lifter body hole center line to keep the spring loaded pin captured inside the body.

These lifters are mass produced , probably with quite wide tolerances and tolerance stack ups.
Lots of moving parts in this lifter.

 

[SyN]

I posted an article months ago within the forum on exactly how these lifters work mechanically... I really am in no mood to search and find it... I do know it is Very Complex and Stupid! With Many Very small holes and openings just waiting to be plugged or blocked with any form of sludge or contamination and Maybe causing some type of oil flow blockage and maybe a malfunction...

Even though the fuel mileage savings is nice with this system... I don't know if it is worth the headache of worrying about it and detail to maintenance is critical...

I feel I need too use an oil with good Moly/Zinc/Calcium/Magnesium count... I need to keep this upper valve train Very Clean and Lubricate the **** out of every moving part the best I can... I have said this many times through out these threads... Also don't over extend your OCI to far! Clean Fresh Oil along with the Use of the Oil Filters we have discussed hundreds of times... Also a Good Filtering Air Filter--->Any dirt particles or any type of contamination that gets past that air filter will eventually end up in your oil...This makes the oil filter have to work twice as hard...

If you chose to keep your MDS system active---> Just try to keep the system Clean and Well Lubricated with the right oil.... And Cross your fingers! Worrying about how it works just wore me out and I really have No time for that..

I personally can't afford to remove these MDS lifters and replace them with the non MDS lifters so the potential malfunction will always be here... I don't think disabling the system with a Tuner will totally eliminate the potential malfunction... From what I have read removing the MDS lifters & replacing with the Non MDS lifters and a Tuner is the only real solution...

 

[Hemi395]

I'm posting a short and poor video of my ECO Light . What I'm doing in the video is : ECO lt. On , then I shift down a gear ECO immediately goes off . Shift back up via button on column and ECO comes back immediately.
ECO still on , turn on tow/hall ECO goes out immediately, turn off tow/hall ECO comes on immediately.

I've heard downshifting one time and tow/hall will turn off the MDS , looks like the ECO indication on dash is directly related to MDS aka 4 cylinders only mode .
I've heard the two systems are separate but the parameters are very close to initiate each ?

What say you MDS experts and motor heads ?



https://vimeo.com/150112412

Thanks for any response .

From what I understand the Eco light comes on when you're driving in an "economical manner". It doesn't necessarily mean MDS is activated. I know in my truck the Eco light is on a lot more than the MDS is active. I really wish it only came on when MDS is active...

 

[R.L.K.]

From what I understand the Eco light comes on when you're driving in an "economical manner". It doesn't necessarily mean MDS is activated. I know in my truck the Eco light is on a lot more than the MDS is active. I really wish it only came on when MDS is active...

Sir , you say "" I know in my truck the Eco light is on a lot more than MDS is activated "" or something really close to that ..

I ask you sir : how do you know that for sure ?

I've read the parameters are very close ; however, I've seen no real data that the two are not directly related ? ( or at least ment to be )

Nevertheless I think and I say ( I THINK ) The ECO light is ment to be a visual representation to the operator that he/she are running on 4 cylinders?

What say you Sir ?

 

[jwheeler]

Sir , you say "" I know in my truck the Eco light is on a lot more than MDS is activated "" or something really close to that ..

I ask you sir : how do you know that for sure ?

I've read the parameters are very close ; however, I've seen no real data that the two are not directly related ? ( or at least ment to be )

Nevertheless I think and I say ( I THINK ) The ECO light is ment to be a visual representation to the operator that he/she are running on 4 cylinders?

What say you Sir ?

He is correct. I have confirmed with a scan tool that the mds is not always activated when the Eco light is on.


Sent from my iPhone using Tapatalk

 

[Hemi395]

Sorry I didn't word that very well. I have a Magnaflow that makes it very obvious when my truck is in MDS. It's borderline annoying actually. Anyways my Eco light is on when I'm giving it very light throttle but it is running on 8 cylinders. Shortly after I can hear it kick down to 4. I do believe that the Eco light has to be on for MDS to activate...

 

[JaredRAM2015]

I just wish manufacturer's gave consumers the option to purchase a vehicle with or without fuel saving technology like MDS. (I know the Government is the reason behind the MPG push and this can't happen)

Every time I buy a vehicle lately is has "engine noise" problems. My 5.3 in the Sierra had piston slap, the LS1 in my Trans-am had piston slap bad. These engines did not have any fuel management, they were just noisy by design!

One of the reasons I loved my 96 Jeep Cherokee 4.0 was how simple the engine was. With the lifter setup on that engine, we ran Rotella 15w-40 or 10w-30 with high zinc, engine loved it!

I guess I just always follow "simple is better"

My 2015 has about 300 miles on it so far. No noise yet, but I assume it is coming!

 

[R.L.K.]

I just wish manufacturer's gave consumers the option to purchase a vehicle with or without fuel saving technology like MDS. (I know the Government is the reason behind the MPG push and this can't happen)

Every time I buy a vehicle lately is has "engine noise" problems. My 5.3 in the Sierra had piston slap, the LS1 in my Trans-am had piston slap bad. These engines did not have any fuel management, they were just noisy by design!

One of the reasons I loved my 96 Jeep Cherokee 4.0 was how simple the engine was. With the lifter setup on that engine, we ran Rotella 15w-40 or 10w-30 with high zinc, engine loved it!

I guess I just always follow "simple is better"

My 2015 has about 300 miles on it so far. No noise yet, but I assume it is coming!

It's coming ... imo change the oil NOW to Redline 5W - 30 with a 100% synthetic filter with a silicone ADBV , such as the Royal Purple 10-48 . Maybe even add a mos2 molly additive .
You'll likely never hear a lifter or valve noise in your ****** ENG.
Disclaimer : This is simply my opinion . I've been running Redline 5W -30 for about 4k , no noise , no issues. ..

 

[Hemi395]

I just wish manufacturer's gave consumers the option to purchase a vehicle with or without fuel saving technology like MDS. (I know the Government is the reason behind the MPG push and this can't happen)

Every time I buy a vehicle lately is has "engine noise" problems. My 5.3 in the Sierra had piston slap, the LS1 in my Trans-am had piston slap bad. These engines did not have any fuel management, they were just noisy by design!

One of the reasons I loved my 96 Jeep Cherokee 4.0 was how simple the engine was. With the lifter setup on that engine, we ran Rotella 15w-40 or 10w-30 with high zinc, engine loved it!

I guess I just always follow "simple is better"

My 2015 has about 300 miles on it so far. No noise yet, but I assume it is coming!

Man you said it. I had a 1987 Jeep Cherokee with the 4.0 I6 and that thing was bulletproof. It had 195k on it when I traded it in and it ran like a champ. The rear main seal went and when I had it replaced my mechanic said the bottom end still looked good.

I agree simpler is better for longevity. I went with a Hemi because I thought it was a pretty simple design. A naturally aspirated pushrod V8. I knew of the MDS system but I figured it simply shut the fuel and spark off. Didn't realize the lifters basically collapsed on cue...

 

[JaredRAM2015]

It's coming ... imo change the oil NOW to Redline 5W - 30 with a 100% synthetic filter with a silicone ADBV , such as the Royal Purple 10-48 . Maybe even add a mos2 molly additive .
You'll likely never hear a lifter or valve noise in your ****** ENG.
Disclaimer : This is simply my opinion . I've been running Redline 5W -30 for about 4k , no noise , no issues. ..

For cost and availability, I was hoping I could get by with Mobil1 and a RP filter... But everywhere I read I see that people have had the same issues with M1...

I will have to shop around locally for the RedLine or order it from amazon or something... I have heard awesome stuff about it. That and Amsoil!

 

[JaredRAM2015]

Man you said it. I had a 1987 Jeep Cherokee with the 4.0 I6 and that thing was bulletproof. It had 195k on it when I traded it in and it ran like a champ. The rear main seal went and when I had it replaced my mechanic said the bottom end still looked good.

I agree simpler is better for longevity. I went with a Hemi because I thought it was a pretty simple design. A naturally aspirated pushrod V8. I knew of the MDS system but I figured it simply shut the fuel and spark off. Didn't realize the lifters basically collapsed on cue...

I sold my Cherokee to my mother in law with a little over 100k miles... I bet that thing will outlast my Ram to be honest!

A little off topic, but man... it is rare that you find a vehicle with a solid engine, transmission AND rear end. Usually you get two, but rarely all 3!

The days of the simple engine are over!

 

[R.L.K.]

For cost and availability, I was hoping I could get by with Mobil1 and a RP filter... But everywhere I read I see that people have had the same issues with M1...

I will have to shop around locally for the RedLine or order it from amazon or something... I have heard awesome stuff about it. That and Amsoil!

Imo ,.Mobil 1 is a good oil , not great but good enogh in most cases , only because they don't come completely clean with what they actually contain in there oil and what generation they should really fall under ...

Amsoil is also a good & maybe great oil choice.
Penzoil Ultra platinum plus ( PUP ) is likely your best OTC and easier to find oil you can use .
Imo and others high Molly &zinc and a robust cleaning agent is highly regarded , an Ester base oil definitely prevails on testing .
You could decifer lots of test results and read thousands of post on chemical contents and what type of lubricity different oil bases and additives provide under an endless cenarios of piston / lifter & valve operations ......or you could just go with an Ester base high molly, zinc and a great additive package for cleaning type oil like Redline .
I personally would go with 30 weight. I have with no issues with MDS or.lifter / valve noise .
Like I've said before the above statements are simply my opinion .
However , my opinions are from countless hours of reading a tremendous amount of boring material.

A few members here that I think are much better versed than myself are : Syn , Burla and raven3

 

[Hemi395]

Redline by far is the best oil you can put in a Hemi. Soaking those lifters in a Ester with high Moly and zinc is the best thing you can do for them. Whether you go 20 or 30 wt, go Redline. Amsoil I would say is a close second although my only experience is with OE.

Just ordered Redline for my next change this afternoon Jegs.com is the best price I could find.

 

[raven3]

This thread took a turn to oil, rather than the mechanical aspects of the MDS lifter & non MDS lifter that cause a noisy hemi.
Get it , you all would rather talk about oil than mechanics.

Have not calculated the shear velocity of the lifter plunger in the lifter sleeve as yet
But would guess the velocity is not sufficient to support a hydrodynamic film.

Not even sure the lifter in v8 mode will take up any pushrod slack like a conventional hydraulic lifter with flat bottom or roller type.
Thinking the POE ester based Redline with high dosage of moly frees up the scuffed up plunger sufficiently, so it starts occilating again.

This lifter has two nested compression springs at the roller end. What's that for , have no clue.
Know the purpose of compression spring on the release pin & the compression follower spring under the plunger.

Agree with Hemi395
Did not figure this hemi had "pogo stick" lifters!
The fuel savings will not even come close to replacing two pairs of MDS filters on one side, if even lifter plunger gets scuffed up and seizes.

In the older vintage type v8's would use Reslone or Marvel Mystery oil to free up stuck lifters and it usually did the trick.

Trying to find the source of the smoke from the internal engine noise & not the leaking exhaust manifold with the broken bolt thing.

 

[Hemi395]

Somewhere online I read about the MDS lifters sometimes failing because the internals move slightly off center from the oil port on the side of the lifter. Pretty sure this was a police Charger that had a lot of idle hours on it. There were pictures showing a normal good lifter and one that that the internals had moved off center. I guess when they move like that it causes the lifter to be solid instead of hydrolic like it should be. This in turn quickly wears out the needle bearing in the roller which causes that to seize and then wear the cam lobe down. If I can find this again I'll post the link.

This is why I don't let my truck idle for more than a few minutes. And if I do let it idle I try to apply slight pressure on the gas pedal to raise the rpm up and oil pressure up slightly. Its also the reason I change the oil much more often than is recommended.