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Re: 2012 ram MDS delete thoughts on this kit [Re: Tay] #3271669
11/21/24 12:14 PM
11/21/24 12:14 PM
Joined: Jan 2005
Posts: 12,501
Kalispell Mt.
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HotRodDave Offline
I Live Here
HotRodDave  Offline
I Live Here
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Joined: Jan 2005
Posts: 12,501
Kalispell Mt.
Originally Posted by Tay
Originally Posted by HotRodDave
Originally Posted by Tay
Delete MDS , install plugs Win Win. as for Pros/Cons , honestly I think it's all subjective , we've had customers say gas mileage was better when towing, ...went to crap when towing, I think some of it has to do with driver habits
for me, personally , I do a lot of short hop driving, 3 miles here, 10 miles there 90% suburbs , mileage went up by 2 , lost 2 on high way , my current daily is a 09 RCSB 4x2 , irony is I got it real cheap because it had a lifter issue

The Lifter issue is a combination of the VVT function, keep in mind certain scenarios the cam is being pulled away from the lifter or snapping back to lock position.
FCA had Comp cams and a private company run a test on a spintron to figure out the issue.



I would love to see any evidence to back that claim up, i seriously doubt it has anything to do with VVT, it is just advancing and retarding it, same thing as increasing or decreasing RPM.


Common sense alone should tell you VVT has something to do with it,....G3 never had a MDS lifter issue before VVT, but after VVT it does,

One of the things discovered during the spintron testing was that when the VVT SNAPS the cam back to lock position there is roughly 3x load on the Camshaft lobe. When retarding the cam they found that in certain situations the plunger in the lifter expands to the point where the contact pressure on the lobe decreases by 50-60% then valve spring pressure takes up that "slack" which creates a bounce

you don't need a masters in Automotive Engineering from University of Wisconsin and 6 years experience working for Stellantis to be able to grasp the root cause.




If you ever opened up a phaser and studied how it works in relation to the complete oil system all together you would see that there is a really big volume of oil in those chambers and you would know that it can only be vented so fast because of basically an orifice allowing it to empty at a certain speed, it can not "snap" back, it takes time for that oil to be vented from the phaser. The FACT is the needle bearing size on the lifter was significantly reduced in 2009 and so a smaller particle of anything can stop one from rolling just like how a penny on the floor in the grocery store can stop your buggy wheel from rolling and it will get a flat spot on the wheel that keeps getting worse as it stops intermittently and skids on the flat spot even more but a train wheel will just keep rolling over one like it wasn't even there. That's why the lifters fail and throwing more oil at it will not do anything to stop it.

I would love to see someone with actual spintron data backing up your claim. Maybe you worked there and couldn't figure this out and that would explain why they are still wiping lobes 15 years after the problem surfaced, if it was snapping back and causing this problem it would be super easy to solve with a computer software update to slow it down even more... Engineers really do some stupid stuff the ordinary everyday man can see is a huge problem but the engineer with his "special education" is clueless.


I am not causing global warming, I am just trying to hold off a impending Ice Age!



Re: 2012 ram MDS delete thoughts on this kit [Re: gtx6970] #3271670
11/21/24 12:19 PM
11/21/24 12:19 PM
Joined: Jan 2003
Posts: 8,105
Tulsa OK
Bad340fish Offline
master
Bad340fish  Offline
master

Joined: Jan 2003
Posts: 8,105
Tulsa OK
I don't see how VVT could cause lifter problems. All it does is move the camshaft a few degrees. It was likely a supplier or design change on the actual lifters that caused the issues.


68 Barracuda Formula S 340
Re: 2012 ram MDS delete thoughts on this kit [Re: HotRodDave] #3271880
11/22/24 03:32 PM
11/22/24 03:32 PM
Joined: Aug 2024
Posts: 23
Quakertown PA
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Tay Offline
member
Tay  Offline
member
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Joined: Aug 2024
Posts: 23
Quakertown PA
all I know is what we found during the sprintron tests.

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