MDS elimination?

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67Dart273

67Dart273

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Someone give me an overview?

When was this implemented in hemis, and can you eliminate it? I'm speaking of course EG buying a used engine, going through it, and changing it to full time V8 operation

So what parts, strategy, "if" etc, can you eliminate MDS?
 
MDS started in 2006 on most vehicles, with the exception of 2500 Ram trucks and a few others. MDS is activated by solenoids in the valley, under the intake. You could simply turn MDS off with tuning and they will never act to deactivate the cylinders. Basically the solenoids hold the exhaust valves open and the ECM cuts fuel and spark to those cylinders.

To fully remove MDS you will need to pull the solenoids, replace them with the truck non MDS block off plugs, then pull the heads And replace the lifters with non MDS and push rods.

I've seen many do just fine by simply turning the MDS system off with a tune, but that's up to the owner of the car.
 
Thanks. There's a '06 hemi for sale locally, torn down, and they said it was running fine with a tick. They said the mechanic found some fine dust in an MDS solenoid. Evidently the entire engine was replaced on warranty. I haven't called them, / don't know if this is a 5.7 or 6.1, or if it has VVT
 
2009 was the first year for the vvt . The 6.1 was the srt performance engine and was never available with mds .
 
My 5.7 is set up with the MDS stuff from the factory, it's an 05/06. I run FAST XFI and therefore cannot just "turn-off" the system. But leaving it unhooked is the same, which is what I have done. From what I understand the MDS lifters do not do well with really big cams, so if your goal was a big ol cam, you need to swap the exhaust lifters and the MDS solenoids with non MDS stuff (plugs from a 2500 truck). I run a moderate cam, (comp cams 268xfi) and have had zero issues with it at all.

Joe
 
Also, just for reference, the solenoids can easily be replaced with plugs by pulling the intake; however, the lifters cannot be replaced without pulling the heads.

Joe
 
Those MDS solenoids in these older engines with high miles are easy to break . The plastic becomes very brittle and the tops break off very easy, the last one I did I ended up drilling a small hole and inserting a small self tapping screw to give me something to pry it out with.
 

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Sounds like if it's torn down it would be easy to remove that stuff anyway.
 
Thanks for the info. Like everything else I do I'll probably screw around and miss the "deal." Suddenly there is a PAIR of hemis available locally. Of course you guys know, these are an expensive swap. I already have one I got into cheap but it also needs a lot of work.
 
There was another thread on here about pace and their new hemi. They disabled VVT through a new timing chain (which also helped with the slop and skip some guys have experienced) and some other mods I can't remember off the top of my head. I think johnnymac was posting in there and could give you more info on how they did it. It sounded like a solid setup.
 
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