Who runs with their MDS off?

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Wild one

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MDS is inactive when in tow/haul mode, which is when the engine will likely be working the hardest. Can you imagine anyone designing an engine in such a way as to provide no oil flow when the engine is under the most demanding conditions?
You're missing one point though Mike,when the engines working hard,the rpms are up,and so is the oil pressure,throw in the fact there's more oil flung off the crankshaft onto the bottom of the lifter body,which is the way the system is designed to be used,it wasn't designed to be deactivated at low rpms when the engine is under a lighter load cruising down the road with the rpms under 2,000. I think alot of guys miss that fact,and that's when you need as much oil flow to the lifters as you can get.
 

Kickboxer

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Where did you get your information about the oiling of the
lifters and those details.?
 

Wild one

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Where did you get your information about the oiling of the
lifters and those details.?
Spend the time to watch these video's,and you'll know more about the hemi's oiling system then most guys




 

mikeru

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You're missing one point though Mike,when the engines working hard,the rpms are up,and so is the oil pressure,throw in the fact there's more oil flung off the crankshaft onto the bottom of the lifter body,which is the way the system is designed to be used,it wasn't designed to be deactivated at low rpms when the engine is under a lighter load cruising down the road with the rpms under 2,000. I think alot of guys miss that fact,and that's when you need as much oil flow to the lifters as you can get.
I see your point Rick. But you aren't necessarily running higher rpm's when tow/haul is active. And MDS will be off as long as that switch is turned on. Good designers take into account the fact that users aren't always going to be predictable. If someone can turn on tow/haul they will turn it on under all sorts of conditions. Good designers wouldn't design something to possibly fail if not used exactly as they expect. Maybe they didn't have good designers when they built the Hemi?

As I brought up in an earlier post, there are several conditions when MDS is not active, some of which can occurs below 2k rpm's. So the engine will be running in 8 cylinder mode under more conditions than just higher rpm's. Just for the fun of it I left MDS enabled on one of my commutes last fall, both to and from work, to see how often MDS comes on. The altitude at work is about 300 feet higher than where I live. And predictably, MDS comes on more on the drive home. In either direction MDS didn't even kick in until I was about 10 minutes into my drive. Likely it waited for oil temps to come up enough. There are small hills and decents in the 25 minute commute. None of the hills is steep enough for the trans to down shift but are enough to kick MDS off. Even when MDS does activate it's only for maybe a mile at a time, then it shuts off for a bit. I would estimate it is active for less than 10% of my commute to work and maybe 20% on the drive home. I can't believe that anyone would have designed an engine to have insufficient oil flow to the valve train for eighty to ninety percent of the time it's running.

I know there is a lot of speculation about this, along with claims that idling causes lifter/cam failures, but I have yet to see actual data which supports that (anecdotal evidence is not data). I mean, I'm a reasonable person. I try to limit my idle time for several reasons. But I'm not buying any claims that disabling MDS is causing lifter damage. I won't argue against the claim that more oil flow a good thing. But I will argue that the designers of this engine took into account the oiling requirements of the valve train under normal conditions...ie, when all 8 cylinders are firing. And I will never believe that disabling MDS is causing engine failures unless someone can show me hard proof otherwise.
 

Dave2015Hemi

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I see your point Rick. But you aren't necessarily running higher rpm's when tow/haul is active. And MDS will be off as long as that switch is turned on. Good designers take into account the fact that users aren't always going to be predictable. If someone can turn on tow/haul they will turn it on under all sorts of conditions. Good designers wouldn't design something to possibly fail if not used exactly as they expect. Maybe they didn't have good designers when they built the Hemi?

As I brought up in an earlier post, there are several conditions when MDS is not active, some of which can occurs below 2k rpm's. So the engine will be running in 8 cylinder mode under more conditions than just higher rpm's. Just for the fun of it I left MDS enabled on one of my commutes last fall, both to and from work, to see how often MDS comes on. The altitude at work is about 300 feet higher than where I live. And predictably, MDS comes on more on the drive home. In either direction MDS didn't even kick in until I was about 10 minutes into my drive. Likely it waited for oil temps to come up enough. There are small hills and decents in the 25 minute commute. None of the hills is steep enough for the trans to down shift but are enough to kick MDS off. Even when MDS does activate it's only for maybe a mile at a time, then it shuts off for a bit. I would estimate it is active for less than 10% of my commute to work and maybe 20% on the drive home. I can't believe that anyone would have designed an engine to have insufficient oil flow to the valve train for eighty to ninety percent of the time it's running.

I know there is a lot of speculation about this, along with claims that idling causes lifter/cam failures, but I have yet to see actual data which supports that (anecdotal evidence is not data). I mean, I'm a reasonable person. I try to limit my idle time for several reasons. But I'm not buying any claims that disabling MDS is causing lifter damage. I won't argue against the claim that more oil flow a good thing. But I will argue that the designers of this engine took into account the oiling requirements of the valve train under normal conditions...ie, when all 8 cylinders are firing. And I will never believe that disabling MDS is causing engine failures unless someone can show me hard proof otherwise.
I have questions about the idling scenario also. Being from Upstate NY literally millions of people remote start their vehicles of all makes and let them idle to warm up when it's between 30 and minus 20 degrees. Also add in traffic jams where one might be idling for an hour such as where I am now by Charlotte NC where it's commonplace to get stuck in traffic for an hour or more sometimes either idling or moving at 5mph. I would think if idling was that big of an issue there would be way more vehicles broke down. ( My truck has 1227 idle hours and 6608 driving hours )
 

Kickboxer

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Spend the time to watch these video's,and you'll know more about the hemi's oiling system then most guys





It seems like reignited is trying to sell higher flow oil pumps.
I suppose you can read lots of things, free world..........
I got that from the internet.......;)
 

Wild one

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I see your point Rick. But you aren't necessarily running higher rpm's when tow/haul is active. And MDS will be off as long as that switch is turned on. Good designers take into account the fact that users aren't always going to be predictable. If someone can turn on tow/haul they will turn it on under all sorts of conditions. Good designers wouldn't design something to possibly fail if not used exactly as they expect. Maybe they didn't have good designers when they built the Hemi?

As I brought up in an earlier post, there are several conditions when MDS is not active, some of which can occurs below 2k rpm's. So the engine will be running in 8 cylinder mode under more conditions than just higher rpm's. Just for the fun of it I left MDS enabled on one of my commutes last fall, both to and from work, to see how often MDS comes on. The altitude at work is about 300 feet higher than where I live. And predictably, MDS comes on more on the drive home. In either direction MDS didn't even kick in until I was about 10 minutes into my drive. Likely it waited for oil temps to come up enough. There are small hills and decents in the 25 minute commute. None of the hills is steep enough for the trans to down shift but are enough to kick MDS off. Even when MDS does activate it's only for maybe a mile at a time, then it shuts off for a bit. I would estimate it is active for less than 10% of my commute to work and maybe 20% on the drive home. I can't believe that anyone would have designed an engine to have insufficient oil flow to the valve train for eighty to ninety percent of the time it's running.

I know there is a lot of speculation about this, along with claims that idling causes lifter/cam failures, but I have yet to see actual data which supports that (anecdotal evidence is not data). I mean, I'm a reasonable person. I try to limit my idle time for several reasons. But I'm not buying any claims that disabling MDS is causing lifter damage. I won't argue against the claim that more oil flow a good thing. But I will argue that the designers of this engine took into account the oiling requirements of the valve train under normal conditions...ie, when all 8 cylinders are firing. And I will never believe that disabling MDS is causing engine failures unless someone can show me hard proof otherwise.
Most of the information is to counteract the guys who swear MDS is the cause of lifter issues Mike,when it has nothing to do with the cam issues. Personally i think 90% of the issues are because they used to soft a cam,not mds as most guys claim. I'm also a firm believer what ever the average owner can do to mininiumize the oiling issue is a good thing,and running with the mds disabled probably isn't the best way to do things. What the video's miss is the lifter body should be a mini pump everytime it goes up and down the lobe,and should actually drip more oil,how much of that oil actually makes it onto the roller will be tough to document,but the more pressure in the lifter galleries feeding the lifter body,the odds of more oil being pushed past the lifter body under a wee bit of pressure to where it might make it onto the roller probably doesn't hurt. Hoover knew there'd be cam issues when he redesigned the block for vvt,and spec'd a billet cam,which would of probably took care of 99% of the issue,but the bean counters took care of that idea when they went with a cast core cam. Once you go to a billet cam,you don't usually have anymore issues with the cam.
I think the stupidest thing they did was move the cam tunnel farther away from the crank and stick the vvt tunnel under it,hell they had to come up with new block cores ,so why not put the vvt tunnel above the cam,and keep the cam closer to the crank,and wide open to recieve all the oil flung off the crank,but oh-no Hoover had to design a valvetrain capable of 8,000 rpm.That's the problem with bringing a retired race engineer back in to design the block,they should of left him at home enjoying retirement in my opinion. I have alot of respect for Hoovers abilities as a race engineer,not so much for his abilities at designing an engine for the average everyday owner who's never gonna race their vehicle,or take it above the factory set 5600 rpm cut off point. To me a little common sense would of had the tunnel above the cam,not below the cam,anybody with an eye and a s s hole would be able to tell blocking the crank splash and moving the cam farther away from the crank isn't the smartest way to design a block,but what do i know,lol
 

Wild one

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It seems like reignited is trying to sell higher flow oil pumps.
I suppose you can read lots of things, free world..........
I got that from the internet.......;)
Yea his theory of using the Hellcat pump isn't really a great theory,i think his video on the mds system is good,but his video about the hellcat pump being the cure all is a bit out in left field as it still doesn't put more oil onto the cam lobe and roller where it's actually needed. You're better off sticking with a stock pump and upping the idle rpm to 750+
 

mikeru

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Most of the information is to counteract the guys who swear MDS is the cause of lifter issues Mike,when it has nothing to do with the cam issues. Personally i think 90% of the issues are because they used to soft a cam,not mds as most guys claim. I'm also a firm believer what ever the average owner can do to mininiumize the oiling issue is a good thing,and running with the mds disabled probably isn't the best way to do things. What the video's miss is the lifter body should be a mini pump everytime it goes up and down the lobe,and should actually drip more oil,how much of that oil actually makes it onto the roller will be tough to document,but the more pressure in the lifter galleries feeding the lifter body,the odds of more oil being pushed past the lifter body under a wee bit of pressure to where it might make it onto the roller probably doesn't hurt. Hoover knew there'd be cam issues when he redesigned the block for vvt,and spec'd a billet cam,which would of probably took care of 99% of the issue,but the bean counters took care of that idea when they went with a cast core cam. Once you go to a billet cam,you don't usually have anymore issues with the cam.
I think the stupidest thing they did was move the cam tunnel farther away from the crank and stick the vvt tunnel under it,hell they had to come up with new block cores ,so why not put the vvt tunnel above the cam,and keep the cam closer to the crank,and wide open to recieve all the oil flung off the crank,but oh-no Hoover had to design a valvetrain capable of 8,000 rpm.That's the problem with bringing a retired race engineer back in to design the block,they should of left him at home enjoying retirement in my opinion. I have alot of respect for Hoovers abilities as a race engineer,not so much for his abilities at designing an engine for the average everyday owner who's never gonna race their vehicle,or take it above the factory set 5600 rpm cut off point. To me a little common sense would of had the tunnel above the cam,not below the cam,anybody with an eye and a s s hole would be able to tell blocking the crank splash and moving the cam farther away from the crank isn't the smartest way to design a block,but what do i know,lol
I couldn’t agree more Rick. MDS can’t be the cause of cam/lifter failures. I had my suspicions with my first Hemi with MDS but a little research was all it took to ease those concerns.

We’ve discussed the soft cam suspicion in other threads, which I also agree with you on. I’m leaning towards installing a billet cam and a proper MDS delete if we’re planning to keep this truck long term. But it’s actually the wife’s truck and she’s been taking about getting rid of it recently and downsizing our stable. Now that we’re retired (as of Jan 1) we don’t really need two trucks anymore. Not to mention that we both have our own cars too. Lol

Like I said in my last post, I can’t argue that more oil flow to the lifters is a bad thing. But I’m not convinced that higher than normal oil flow part of the time is going to do much to make the cam/lifters last longer.
 

Wild one

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I couldn’t agree more Rick. MDS can’t be the cause of cam/lifter failures. I had my suspicions with my first Hemi with MDS but a little research was all it took to ease those concerns.

We’ve discussed the soft cam suspicion in other threads, which I also agree with you on. I’m leaning towards installing a billet cam and a proper MDS delete if we’re planning to keep this truck long term. But it’s actually the wife’s truck and she’s been taking about getting rid of it recently and downsizing our stable. Now that we’re retired (as of Jan 1) we don’t really need two trucks anymore. Not to mention that we both have our own cars too. Lol

Like I said in my last post, I can’t argue that more oil flow to the lifters is a bad thing. But I’m not convinced that higher than normal oil flow part of the time is going to do much to make the cam/lifters last longer.
Personally i think one of the best things i did to my truck,was replace the cam with a good one ,along with the non-mds aka Hellcat lifters,plus use the mds aluminium block off plugs from Roger Stanke,and install the Mopar hi-po 0.625 lift valve springs,and also up the idle rpm to 750.Being a Canuck it made my rear pucker from the cost though,lol. It was over $4,000 Canuck to do it the way i did almost 10 years ago,but that also included Trend pushrods / Ma Mopars valve train stabilizing steel tie bars which they don't make anymore / ARP head bolts etc.
But 700 nitrous fueled dragstrip passes ,shifting at 6600 rpm,and 50,000 mile of spirited driving later,and the engine was still rock solid when i sold the truck
 

Marshall

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I find the easy way to turn off MDS is just put your foot into it, plus at my age , I can't hear the exhaust unless I really get into it , or open windows, and in winter in Canada , I an't opening no windows.
I mainly use the buttons to keep the RPM's up when diddling around town at 20mph on the ice, or behind all the minivans from the seniors condo up the street.

PS, On a good day on good road, I have had the ecno light come on at 120KM/ 70+mph, but a little hill will turn it off, I can't feel the difference, and the green gauge don't really care.
I just lit it do it's thing most of the time.
 

Dodge 1500 4X4

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I disable mine every time W gear - + on steering wheel, higher idle rpm would put more oil splash on lifter/ rollers that would help allot, I don't remote start my truck and don't let it idle excessively, I also use a Lubrication Strategy for peace of mind.
 

Wild one

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Driving a Hemi like you're 16 again,is one of the best things you can do to keep it happy,lol
It's driving them like Grandma Jones that they don't like,lol
They might not pass as many gas stations,but they usually don't have as many cam issues either ;)
 

Dave2015Hemi

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Driving a Hemi like you're 16 again,is one of the best things you can do to keep it happy,lol
It's driving them like Grandma Jones that they don't like,lol
They might not pass as many gas stations,but they usually don't have as many cam issues either ;)
Ha Ha That's the way I drive mine most of the time!
But also, I think what is missed a lot too is pretty much every video you see of the lifters being replaced shows a bad lifter that "failed" and took out a lobe and either seized or the bearings got loose but they always show the other lifters and most of the ones that didn't actually seize and take out a cam lobe are also 80% gone and either wobbly or super loose and just haven't seized yet. I think that is a main part of the issue. I hear other people talk about "squirters" on other brands and am surprised Chrysler hasn't come up with some retrofit of something to put inside the block to get more oil dripped or squirted on the cam directly. More volume or flow would always be better but only if it actually gets to where it needs to be. Why not bigger needle bearings for all lifters like some picture shows vs the tiny ones that we all know will not last 6000 rpm for years! Or some completely new design. Do they not have outside the box thinkers like Johnson?
 

Wild one

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Ha Ha That's the way I drive mine most of the time!
But also, I think what is missed a lot too is pretty much every video you see of the lifters being replaced shows a bad lifter that "failed" and took out a lobe and either seized or the bearings got loose but they always show the other lifters and most of the ones that didn't actually seize and take out a cam lobe are also 80% gone and either wobbly or super loose and just haven't seized yet. I think that is a main part of the issue. I hear other people talk about "squirters" on other brands and am surprised Chrysler hasn't come up with some retrofit of something to put inside the block to get more oil dripped or squirted on the cam directly. More volume or flow would always be better but only if it actually gets to where it needs to be. Why not bigger needle bearings for all lifters like some picture shows vs the tiny ones that we all know will not last 6000 rpm for years! Or some completely new design. Do they not have outside the box thinkers like Johnson?
The wrist pin / piston squirters they use in the 6.1's / 6.2's and 6.4's could easily be reconfigured to spray oil onto the cam lobes
 
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