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

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mikeru

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Thinking about it more: if increasing idle to 750+ helps, then why does disabling MDS matter? Either it gets lubed enough at 750 rpms, or it doesn't. If disabling MDS is damaging the lifters at 1200 driving down the road then there is no point in increasing your idle rpms.

Either the crank throws enough splash at a given RPM or it doesnt, so those 2 ideas kind of conflict with eachother, right?

Same with combining "no idle" with increase idle rpms. If raising your idle helps, then it should be able to idle for hours with 0 issues.

Just the more I think about it the more confused everything seems.

I still think this is like a wheel bearing; some wheel bearings fail at 50k miles, and the others on the truck fail at 150k miles. Nobody starts thinking there is not enough cooling/air flow to the wheel (or whatever), we just accept its a bad/poorly made part that failed before its time. Yet with lifters we're all so eager to find overly complicated theories and solutions.
As stated several times throughout the thread, it's a theory. No one has been able to prove that disabling MDS causes more lifter wear. Just like it's a theory that MDS is the cause of lifter failures. People come out with videos to present their theories on lots of stuff. And may provide some anecdotal evidence. But they rarely provide conclusive supporting data. Sometimes theories are all we have to go on. All you can do is base your decisions on what make the most sense to you.
 

Black1500Ram

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That's good to know. Not surprising either. That would help explain why the cam wears to a degree, but it doesn't explain the lifter rollers failing. From what I've seen it's the lifters which fail first, then taking out the cam.
Can’t say this to be 100%

I just looked at my failed cam again and a number of lobes have wear, pitting etc.

The only lifter that wasn’t free rolling, and showed any sign of wear is on the one that corresponds to the severely chewn lobe (cyl 5, non mds).
IMO the lifter failing is the result not the cause.
 

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ramffml

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Can’t say this to be 100%

I just looked at my failed cam again and a number of lobes have wear, pitting etc.

The only lifter that wasn’t free rolling, and showed any sign of wear is on the one that corresponds to the severely chewn lobe (cyl 5).

That looks pretty terrible. What was your oil choice (brand + viscosity) and change/interval when that happened?
 

mikeru

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Can’t say this to be 100%

I just looked at my failed cam again and a number of lobes have wear, pitting etc.

The only lifter that wasn’t free rolling, and showed any sign of wear is on the one that corresponds to the severely chewn lobe (cyl 5, non mds).
IMO the lifter failing is the result not the cause.
That would certainly support the inferior cam theory. Why no pics of the lifters?
 

ramffml

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Pup 5w20 fram xg10060 5k religously from 27k to 117k when i did the replacement. Idle hours are 15% of total

In that thread you mentioned getting excessively hot temps (260) and having to reduce towing speed, that may have been part of the problem in your case, that's one reason I run a 30 weight and keep temps down at all costs.

Edit: Burla has posted a report from an engineer who looked at these cams, and that engineer noted how the cam was damaged due to the inability of the oil to reduce the friction - or something to that effect. Forget the exact wording. So the engineers view was that the oil was there (getting lubed), but the oil didn't have the right additives or whatever to do its job.

Have to admit I find that theory very plausible as well, but still it doesn't explain why 1 lifter fails and 15 in the same engine don't.
 
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Wild one

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In that thread you mentioned getting excessively hot temps (260) and having to reduce towing speed, that may have been part of the problem in your case, that's one reason I run a 30 weight and keep temps down at all costs.

Edit: Burla has posted a report from an engineer who looked at these cams, and that engineer noted how the cam was damaged due to the inability of the oil to reduce the friction - or something to that effect. Forget the exact wording. So the engineers view was that the oil was there (getting lubed), but the oil didn't have the right additives or whatever to do its job.

Have to admit I find that theory very plausible as well, but still it doesn't explain why 1 lifter fails and 15 in the same engine don't.
Makes me think that once a lifter goes,it's usually only a matter of miles before it's gouged the cam to the point you get a misfire,and if you were to keep driving it,the rest of them might also go .Check out BR1500's pics in post 142,there was more then one lifter getting ready to go south,which seems to be fairly common. It would only be a matter of a bit more time before he would of had a bunch of bad lifters
 

Black1500Ram

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Makes me think that once a lifter goes,it's usually only a matter of miles before it's gouged the cam to the point you get a misfire,and if you were to keep driving it,the rest of them might also go .Check out BR1500's pics in post 142,there was more then one lifter getting ready to go south,which seems to be fairly common. It would only be a matter of a bit more time before he would of had a bunch of bad lifters
Here’s the crazy part… I had no codes no misfires
 

Dan Topp

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Reading all these horror stories reminds me of the scary stories I was bombarded with when all the GM LS7 trunion bearings were falling apart and now any aftermarket valve train uses bushings instead of needle bearings. So I’m requesting a cam and hellcat lifters ect.when I do the headers on the 5.7.No way I’m gonna grind up my hemi knowingly. So Thanks Wild one
 
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Bmags

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This. The truth is out there.

That said, I personally hate loss of power, crappy sound and generally not having the V8 I paid for… which is why I’ve disabled DOD/MDS/whatever in every truck I’ve owned since this became a “feature.” Shame it’s such a big deal for our trucks.

Taking the middle road now and only selectively disabling when it particularly bothers me until I can do a proper (expensive!) delete.

No excuse by now for not being aware of the impact it can have!
So many people keep using this buzz word of “proper delete”… and seem to completely disregard the fact that factory non-MDS engines also suffer from cam/lifter failure.

The issue with cam/lifter failure is therefore not tied to MDS activation or a lack of oil from MDS never turning on, otherwise we wouldn’t see the factory non-MDS engines have failure!

Also, just to be clear, in my truck I only turned MDS off, I didn’t mess with my idle speed at all.
 
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Wild one

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So many people keep using this buzz word of “proper delete”… and seem to completely disregard the fact that factory non-MDS engines also suffer from cam/lifter failure.

The issue with cam/lifter failure is therefore not tied to MDS activation or a lack of oil from MDS never turning on, otherwise we wouldn’t see the factory non-MDS engines have failure!

Also, just to be clear, in my truck I only turned MDS off, I didn’t mess with my idle speed at all.
That appears to be working for you,but for the next guy it might not work. As in why do some trucks last 200,000+ miles with no manifold or cam and lifter issues,but the next guy with the identical truck has done exhaust manifolds twice by a 100,000 miles,and a cam and lifters at 60,000 miles.
There's really no ryhm or reason to why some trucks have no issues,and some do,so to use your personal experiences and claim everybody will have no issues,because you haven't had any,doesn't really stand the testment of time.
 

Dan Topp

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So many people keep using this buzz word of “proper delete”… and seem to completely disregard the fact that factory non-MDS engines also suffer from cam/lifter failure.

The issue with cam/lifter failure is therefore not tied to MDS activation or a lack of oil from MDS never turning on, otherwise we wouldn’t see the factory non-MDS engines have failure!

Also, just to be clear, in my truck I only turned MDS off, I didn’t mess with my idle speed at all.
Hellcat oil pump?
 

Bmags

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That appears to be working for you,but for the next guy it might not work. As in why do some trucks last 200,000+ miles with no manifold or cam and lifter issues,but the next guy with the identical truck has done exhaust manifolds twice by a 100,000 miles,and a cam and lifters at 60,000 miles.
There's really no ryhm or reason to why some trucks have no issues,and some do,so to use your personal experiences and claim everybody will have no issues,because you haven't had any,doesn't really stand the testment of time.
You’re missing the point of my post, let me try again. I agree, my results are irrelevant… it’s a sample size of 1 compared to the million of engines out there.

I’m saying there is no such thing as a “proper delete”. ALL Hemi engines have had some amount of cam/lifter failure, and I see no conclusive evidence out there that says I’m any MORE likely to have a failure with my MDS turned off compared to a stock engine running with MDS as intended… or for that matter a stock engine that never had MDS to begin with!

That’s what this whole post is about right? You warning people not to delete/bypass MDS with a tune, but to instead do it “properly”…

Yes these engines may have a design flaw that chews up cams, but it’s not the MDS oiling that’s causing it.
 

BlackSheepRebel

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So many people keep using this buzz word of “proper delete”… and seem to completely disregard the fact that factory non-MDS engines also suffer from cam/lifter failure.

The issue with cam/lifter failure is therefore not tied to MDS activation or a lack of oil from MDS never turning on, otherwise we wouldn’t see the factory non-MDS engines have failure!

Also, just to be clear, in my truck I only turned MDS off, I didn’t mess with my idle speed at all.
“Proper delete” means replacing the hard parts not just pushing a button to disable solenoid activation. Based on videos I’ve seen that open up the engine and trace oil paths, this is the only way to disable MDS (which I hate for the record) without starving the lifters of oil.

 

Bmags

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“Proper delete” means replacing the hard parts not just pushing a button to disable solenoid activation. Based on videos I’ve seen that open up the engine and trace oil paths, this is the only way to disable MDS (which I hate for the record) without starving the lifters of oil.

Oh, so if I do that I won’t have cam and lifter failure?!?!

Wait a minute… doesn’t this mean you are making it look like a factory non-MDS engine? Don’t those also have cam and lifter issues?

Oh they do? So that makes this proper because…
 
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Wild one

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You’re missing the point of my post, let me try again. I agree, my results are irrelevant… it’s a sample size of 1 compared to the million of engines out there.

I’m saying there is no such thing as a “proper delete”. ALL Hemi engines have had some amount of cam/lifter failure, and I see no conclusive evidence out there that says I’m any MORE likely to have a failure with my MDS turned off compared to a stock engine running with MDS as intended… or for that matter a stock engine that never had MDS to begin with!

That’s what this whole post is about right? You warning people not to delete/bypass MDS with a tune, but to instead do it “properly”…

Yes these engines may have a design flaw that chews up cams, but it’s not the MDS oiling that’s causing it.
The post is more about educating guys of how the system operates ,then it is about deleting the mds.
Nobody can really comment about whether the mds is the issue or not,but if you have one of the trucks with tolerances not as good as say your truck,they might be the guys that shouldn't be defeating it via the +/- buttons or a tune,as it might contribute to an earlier lifter failure on their truck.
I'm not here to argue the point,all i'm trying to do is give guys more information to work with,as evidenced by this thread.
If you can find anything that says it's good to defeat the mds via the buttons or tune,please post that info,as the whole purpose of the thread is information to learn from,nothing more / nothing less. Not to argue or be confrontational.
 
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Lsujker

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I for one have been running with my MDS on sense reading this thread. However, the driving dynamic has been unpleasant. My thought. Keep turning it off every drive. Assuming a 12k average every year with an estimate lobe destruction at 120k, I have 10 years. Thinking I will be making more money by then with carrier growth, a cam replacement should be within my budget… crap, forgot about inflation.

Look, y’all need to figure this out.
 
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Black1500Ram

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Has anyone got any knowledge of oil flow in an mds engine when functioning in 8 cyl?
It is far more often than not that the engine operates with 8 cyl. so the mds solenoids are closed limiting pressurized oil to the lifter bore.
There HAS to be oil still getting to the lifters for proper lubrication of the engine.

I'm honestly contemplating buying a block just to study all this.
 
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