MDS hemi lifters

[raven3]

RLK
Before adding Redline was your hemi noisy just at start up , during warm up period, or continuous after warm up or all of the above situations?
And
What is model year of the engine?

Still looking for the source of the hemi noise.

Thank you in advance

 

[R.L.K.]

2014 5.7L 4x4 QC 6 speed xsmn with 3.55 differential gear ratio .
Driven miles per year avg . 16,500

My 5.7 has never had the " hemi tick " at any spectrum .
I felt the eng was just loud during normal operations. Start , during warm up and while @ operating temp.

 

[raven3]

Piston slap could be a source of hemi noise.
Weisco manufactures pistons for the 4th generation hemi engine.
The piston has a very short skirt.
The skirt only covers two sides, while the forward and aft regions are void of skirt material.
Weisco mentions noise in the piston description .
The piston skirt surface is coated to reduce noise and reduce friction and associated scuffing against the cylinder wall.
The Weisco piston material is 2618 aluminum which allows a .004" piston clearance to piston wall.
Other piston materials include, hypereutectic and cast aluminum.
If the OEM piston is standard non performance cast aluminum material, clearance is a minimum of .008" .
The Morpar OEM piston may not include a coating to reduce noise and friction.
The large piston clearance combined with a partial short skirt design could cause noticable noise.

A high moly additive concentration in the motor oil could reduce the impact scuffing noise associated with piston slap or rattle
by cushioning the metal to metal

 

[raven3]

Found a graphic of used 2009 OEM hemi 5.7 piston on e-bay.
The piston has a protective anti scuff coating on the small partial skirt.

 

[raven3]

If piston slap is a source of hemi noise, all eight pistons would generate equal noise.

If a stuck lifter was another source of noise the frequency of the metal to metal impact would 1\2 the chankshaft rpm.
So at idle engine of ~700 rpm the frequency of impact between roller and camshaft lobe would be ~ 350 times\minute or once\ second.
Chances are only one or two MDS type lifters would get stuck when transitioning between 4 to 8 cylinder mode.
The top hydraulic lifter section could jam when sliding within the outer main lifter body.

 

[Hemi395]

I'm pretty sure my Hemi some piston slap. Here's a thread I started over the summer of a noise my engine makes when it's cold. It's only gotten louder since its gotten cold here. Dealer said its "normal startup noise".

http://www.ramforum.com/showthread.php?t=72239

 

[R.L.K.]

I'm pretty sure my Hemi some piston slap. Here's a thread I started over the summer of a noise my engine makes when it's cold. It's only gotten louder since its gotten cold here. Dealer said its "normal startup noise".

http://www.ramforum.com/showthread.php?t=72239

Most dealers are idiots, and there go to analysis of most customer complaints are " that's normal" or " I don't hear anything " or sorry but you haven't documented all routine & factory scheduled maint With reciepts so your warranty may be voided ....
There are good dealers out there but good luck finding one .
I believe I've found a good one .

 

[Hemi395]

Most dealers are idiots, and there go to analysis of most customer complaints are " that's normal" or " I don't hear anything " or sorry but you haven't documented all routine & factory scheduled maint With reciepts so you warranty may be voided ....
There are good dealers out there but good luck finding one .
I believe I've found a good one .

Yeah mine is definitely not the greatest. Not terrible but not great. The next closest one is 75 miles away and I'm debating going there...

 

[R.L.K.]

Damn ! I bet i.have 10+ in 75 miles

 

[raven3]

Found a really qualified RAM service representative that was an air force jet mechanic, understands that RAM inside & out.
If the noise is more of a Clatter sound would guess the source is either piston slap or valve stem wobble.
If the noise is more like bang bang thing would guess the source is a stuck lifter.

 

[Limeybastard]

It's the lifters 100%

Had that issue with my truck every cold crank, would sound horrible.

Replaced the lifters with non-MDS and longer pushrods with my cam swap, sound is completely gone. No more ticking and cold starts are quiet.

Lifters...

Most vehicles I've owned made lifter noise on cold start up especially high mileage ones. , a very light clackety top end noise, duration would he longer if freezing weather was present.
I think my Ram does it also on start up a slight top end rattle noise that goes away after a few seconds. Oil starvation on top end perhaps. Who knows.
With cold temp I'm referring to 64 F ambient temp over night or if the vehicle has been stationary for a few hours. I'm sure the duration of the noise will get longer as mileage creeps higher.

Sent from my SM-N910T using Tapatalk

 

[raven3]

Have a theory on top end, so called, oil starvation upon start up.
What if the anti back flow valve(rubber flapper) in the spin on oil filter, leaks, while the vehicles is non operational.
I know the filter is in a vertical position and the oil from the filter canister will not gravity flow out of the canister, as with a horizontally mounted filter.

Oil could "siphon" from the oil filter canister to the bottom of the sump through a leaky rubber flapper , since the surface of the oil sump is lower than the oil filter.
The flow passage is from the exterior of the filter media through the rubber flapper, through the office holes in the base plate, through the engine passage to the oil pump , through the engine passage to pick up tube in sump and finally through the pick up tube submerged in the oil sump. If this flow path is not vented to atmosphere, then the oil could then siphon upward out of the filter through the engine , then downward into the sump.

Now, the filter must fill with oil before any oil is pumped to the top end. The hemi lifters are feed from the top rocker assembly. Mean while, the MDS lifters are floating with push rod slack causing clatter. Maybe all eight MDS lifters are noise makers, causing the clatter, rather than just one stuck lifter.

The high end filters use a silicone rubber flapper rather than a nitrile rubber flapper which is less flexible and hardens with oil temperature.

 

[R.L.K.]

This is exactly the reason why so many are recommending synthetic high flow filters with a silicon ADBV .
Such as but not limited to RP 10-48 Filter

 

[raven3]

If the oil actually siphons from the filter to the sump something must trigger or cause the oil to flow.
Would guess the thermo gradient created between the hot oil when it cools is sufficient to cause the flow.
That is ,A temperature difference of the oil is created between the filter and the sump.
The oil in the filter would cool faster than the oil in the sump.
Was always a student of physics.

 

[Nutshell]

What about the weight of the oil above the sump? Due to the difference in height, one would assume the oil level would try to find its equilibrium once pump operation has ceased. Again, my assumption would be that the height of that point is below the lifters.

 

[Nutshell]

Lifters have bled down and lost preload. That is the issue.

Correct. The question is why???

 

[raven3]

Some folks complain of clatter type noise even relitively newer engines.
Could be a clearance tolerance issue
between the plunger and outer body
on MDS & non MDS lifters.
The MDS lifters have two side holes &
two pins on opposite sides of the main body. The two spring loaded pins maintain the lifter in solid mode with no pressure applied to the two side holes. When oil pressure is applied to the two holes, the pins unlatch allowing the top hydraulic lift to side within the main body of the lifter.
Affective my closing both intake and exhaust valves. When the air is compressed the engine perform work and when the piston moves downward the work is recovered, resulting in net zero work , except the work of friction.

 

[SyN]

The nature of MDS lifters, they have a hole in the side to activate or deactivate. So they are more common to bleed down, adding a longer pushrod will give more preload and prevent lash even if they bleed down a little.

I have read about this and when they do replace the cam and MDS lifters with non-MDS lifters they also replace the pushrods with longer ones...

Everyone that I have read about-->After doing this the Tick or Noise was gone... At start-up and during cold Idle as well as operating temp idle...

I just hope I don't ever have to go through all of that...

 

[raven3]

The top section on the MDS lifter is built like a hydraulic lifter, except oil feed is from the top rocker assembly.

Noticed the MDS lifter part # for 2014 & 2015 is different than 2010 -2013.
2006 -2009 is different than 2010-3013.

 

[raven3]

TheHack
On the engine with all non MDS replacement lifters
Did the OE engine have chatter at start up, warm up period & operating temperature or all of the time periods?
What was the build year of the engine?

On the MDS lifter there is only two flow paths for oil to exit the top hydraulic lifter,
perimeter between plunger & retainer body
and
hole at top of lifter(push rod cap).
The top section of the lifter that slides inside main outer body has a flat bottom with no holes.