Another ticking 5.7L Hemi

[HEMIMANN]

The MDS plugs virtually copy cat the engine being in full time MDS mode Mike.They supply constant oil pressure to all the lifters all the time. Fast forward the video to about the 24:30 minute mark Mike,and he explains the plugs a bit better. I've been running the billet Stanke block off plugs for about a 1/2 dozen years,and they work good,buy either the Mopar or Stanke billet plugs,don't buy the cheapy Chinese knock off plugs,as they've been known to give issues

How difficult are those solenoids to get at? Remove intake manifold and you're there? If so, that would be a much handier band aid than a higher flow oil pump, wouldn't it?

 

[Wild one]

How difficult are those solenoids to get at? Remove intake manifold and you're there? If so, that would be a much handier band aid than a higher flow oil pump, wouldn't it?

Pretty much,but that would put the engine in MDS mode all the time,unless you swapped out the MDS lifters,at least that's my thinking. For awhile i was a fan of the Hellcat pump,but now i'm not so sure where i stand on the Kitty's pump,i think i'd be more inclined to use Mellings high volumne pump,with their 60 psi spring instead of the Hellcat pump.But that's only my thoughts,and they don't go very far,lol

 

[HEMIMANN]

Pretty much,but that would put the engine in MDS mode all the time,unless you swapped out the MDS lifters,at least that's my thinking. For awhile i was a fan of the Hellcat pump,but now i'm not so sure where i stand on the Kitty's pump,i think i'd be more inclined to use Mellings high volumne pump,with their 60 psi spring instead of the Hellcat pump.But that's only my thoughts,and they don't go very far,lol

Ah, duh! I didn't think it through (again). Yep - a good fix would get rid of MDS lifters and block the solenoid ports. It might have a chance of lubricating lifter roller & cam like a normal engine then.

Which makes me wonder - did the pre-MDS engine block not have an oil galley for the lifter bore (because no MDS push-pin to actuate)? i.e. - were they relying 100% on splash-up oil for the cam?

Your thoughts carry a lot of weight around here, so don't sell yourself short. The dude's video said the Hellcat oil pump was a direct fit on post-2009 model year Hemi's. It implies Melling wouldn't fit, to me.

Basically, these two major mods are about re-designing the Hemi as it should have been in order to be sufficiently lubricated. What a terrible thing to say about a base engine design!

 

[Wild one]

Ah, duh! I didn't think it through (again). Yep - a good fix would get rid of MDS lifters and block the solenoid ports. It might have a chance of lubricating lifter roller & cam like a normal engine then.

Which makes me wonder - did the pre-MDS engine block not have an oil galley for the lifter bore (because no MDS push-pin to actuate)? i.e. - were they relying 100% on splash-up oil for the cam?

Your thoughts carry a lot of weight around here, so don't sell yourself short. The dude's video said the Hellcat oil pump was a direct fit on post-2009 model year Hemi's. It implies Melling wouldn't fit, to me.

Basically, these two major mods are about re-designing the Hemi as it should have been in order to be sufficiently lubricated. What a terrible thing to say about a base engine design!

They added an extra oil galley for the VVT,and that also moved the cam tunnel up in 09,and that's when we really started to see the lifter issues. Prior to moving the cam tunnel,the Hemi didn't really have a rep of chewing up lifters. The Melling pump is a direct fit to,he was working with the earlier 5.7 with-out VVT and that's why he had to modify the timing cover to fit the Hellcat pump.The timing cover also changed in 09 to allow room for upper VVT cam sprocket. Apparently the engineers spec'd a billet camshaft for the redesigned VVT Hemi's,so i'm guessing they knew there'd be issues with the relocated cam tunnel,but of course what the engineers spec,doesn't always make it past the bean counters.

 

[HEMIMANN]

They added an extra oil galley for the VVT,and that also moved the cam tunnel up in 09,and that's when we really started to see the lifter issues. Prior to moving the cam tunnel,the Hemi didn't really have a rep of chewing up lifters. The Melling pump is a direct fit to,he was working with the earlier 5.7 with-out VVT and that's why he had to modify the timing cover to fit the Hellcat pump.The timing cover also changed in 09 to allow room for upper VVT cam sprocket. Apparently the engineers spec'd a billet camshaft for the redesigned VVT Hemi's,so i'm guessing they knew there'd be issues with the relocated cam tunnel,but of course what the engineers spec,doesn't always make it past the bean counters.

Thanks for info - this all adds up.

I doubt the billet camshaft made much difference with the cam surfaces hardened into the high Rc's regardless. Just a little less surface porosity is all for sintered or cast.

I recall one of the lifter / cam failures I read in the forum had the intact cams hardness tested, and the result was Rc 59 - definitely a hardened cam surface. We don't know whether it met the design spec, but this level of hardness is definitely in the upper echelon of material hardness. It proves that there wasn't an issue with improperly hardened cam surfaces. It's lack of lubrication.

Specifically, what I'm wondering is if the MDS actuator oil galley was added. Prior to VVT and MDS, with the cam bore lower and the valve bore angle less flat, maybe oil drainback down the lifter bore was just good enough not to have so many failures?

 

[Black1500Ram]

Ah, duh! I didn't think it through (again). Yep - a good fix would get rid of MDS lifters and block the solenoid ports. It might have a chance of lubricating lifter roller & cam like a normal engine then.

Which makes me wonder - did the pre-MDS engine block not have an oil galley for the lifter bore (because no MDS push-pin to actuate)? i.e. - were they relying 100% on splash-up oil for the cam?

Your thoughts carry a lot of weight around here, so don't sell yourself short. The dude's video said the Hellcat oil pump was a direct fit on post-2009 model year Hemi's. It implies Melling wouldn't fit, to me.

Basically, these two major mods are about re-designing the Hemi as it should have been in order to be sufficiently lubricated. What a terrible thing to say about a base engine design!

You also need to turn off mds in the pcm which needs a tune. Can’t just pull the hardware without changing the software.

 

[Wild one]

You also need to turn off mds in the pcm which needs a tune. Can’t just pull the hardware without changing the software.

I wonder about that,sure it would throw a code,but would it actually affect how the truck would run.Only downside with a code ,you have no cruise or remote start,and that would leave a bit to be desired,lol

 

[Black1500Ram]

I wonder about that,sure it would throw a code,but would it actually affect how the truck would run.Only downside with a code ,you have no cruise or remote start,and that would leave a bit to be desired,lol

when in mds mode, valves aren’t opening in 4 cylinders, so the pcm shouldn’t be spraying fuel or igniting the spark plug in those cylinders. That’s what turning mds off in the pcm should be accounting for.