StateOfMind
Senior Member
- Joined
- Oct 3, 2023
- Posts
- 231
- Reaction score
- 391
- Location
- Orange County CA
- Ram Year
- 2018
- Engine
- 5.7 Hemi
This might be the most entertaining thread to date
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If you delete the lifters,your hemi isn't going to run very good,lifters are kind of essential to a hemi,lol. You replace the mds solenoids with the block off plugs,and swap the mds lifters to non-mds lifters,you should also replace the cam with a non-mds cam.I would surmise that most of the over all failures to date are statistically owners who have either not deleted the lifters or never turn off mds. So im doubting this one. Ill be the guinea pig. Been turning mine off everytime i get on the highway and always will. 20K miles with it being off as of now. I also pretty much never idle. If im going to sit more than a minute, im in neutral at 1200 or so.
and merely leaving the truck parked in the driveway will cure lifter/cam failures! LOL!Modern Muscle Xtreme
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We have added a new section to the website for Hemi Tech articles! Below is our latest addition regarding Lifter failure in the G3 HEMI engine.
Gen 3 Hemi Lifter Failure, Hemi Tick, and P0300.
First, I would like to start off by saying, there is a large quantity of misinformation and BS on the internet regarding the Gen 3 Hemi’ s lifter issues. I have seen all sorts of theories, and “install this part to CURE your hemi engine” posts in forums and all over YouTube. Let’s first look at how the Hemi engine oils to better understand this failure. The main hydraulic lifter feed in the G3 Hemi oils backwards from most every other conventional pushrod V8 engine on the market. The oil travels up through a passage at the deck of the engine block, through a restrictor in the head gasket, up around the head bolts, up through a passage in the head, into the rocker shaft, from the rocker shaft through the rocker body to the pushrod, down the pushrod and finally into the lifter. In terms of how the MDS system operates, when the 4 solenoids located on top of the block open, this sends oil flow and pressure around the body of the MDS lifters to compress the plunger/check ball located on the side of the MDS lifter. When this is compressed, the hydraulic portion of the MDS lifter collapses, and the engine runs in 4-cylinder mode. Unlike GM DOD engines, the typical failure is not the actual hydraulic portion, it’s the lifter axle bearings that fail. When this occurs, the roller wheel starts to skid on the lobe of the camshaft and grind through it sending metal all through the engine. The early signs of lifter failure are a slight tick that can be audibly heard when the engine is running at idle. Later signs of failure include a P0300 code indicating a misfire. Further engine damage can be prevented by CEASING TO RUN THE ENGINE AFTER THE P0300 CODE POPS UP. Many shops and customers will unfortunately waste time/money by trying to replace a coil pack or injector for the cylinder that is misfiring, but 95% of the time P0300 code is present, a lifter axle bearing has already failed and is griding away into the camshaft. This leads us to the question, why does this system fail?
In my opinion the root cause of failure is a two-part problem. Issue #1 is the design of the needle bearings of the lifter. The very early HEMI engines had large roller bearings (and a smaller axle) on their lifters. For some unknown reason, Chrysler went away from this design, and made the needle bearings much smaller, and the axle larger. These small bearings do not seem to take the load of being constantly activated and deactivated as well as the early design lifters. The second issue is lubrication. As I mentioned earlier, the only way the actual lifter bore in these engines receives any oil is when the MDS solenoid opens to deactivate the 4 cylinders worth of lifters. This means that during idle, and when the MDS is not active, the body of the G3 Hemi lifter receives NO OIL! (Mild caveat here, the lifter does receive some splash lube up from the crankshaft, but it is VERY minimal as the main oil galley blocks a very large portion of the potential splash lube. Combine this with the very high cam/crank centerline (7.464 Inches-compare that to a small block chevy at 4.521”) and the potential for the lifter to get any splash lube is near zero.
The next logical question is, how to we fix it? We address the two issues I mentioned earlier (Needle bearing Size, and Lubrication). The Latest design 8784AD NON MDS lifters (Hellcat Lifters) have larger roller bearings, so this takes care of problem number one. To remedy problem number two, we simply need to install MDS plugs into the block. Installing the MDS plug allows for full flow of pressurized oil to go around the body of the lifter, and drip down on to the roller wheel to properly lubricate the bearings.
In summary, the fix is an MMX MDS Delete Kit. Our kits include the NON MDS Camshaft, NON MDS Hellcat Lifters, MDS Plugs, and other supporting hardware. This fully takes care of the needle bearing issue, and the lubrication issue. Buying quality oil and having a frequent oil change interval also helps tremendously with keeping the factory MDS system functioning for as long as possible.
-Byron Walker
The best thing you can do to a hemi,is drive it like you stole it,babying them doesn't do the engine any good.Owned since new, 67K and always put it in "8th gear" from the start. The last 20K+ on the tune with MDS deleted.
I run the truck regularly to 5K+ rpm, no issues to date...*Knocks on wood*
The best thing you can do to a hemi,is drive it like you stole it,babying them doesn't do the engine any good.
Only problem with driving like you stole is the transmission doesnt like to be beat on. The engine always handles it just fine but trans not so much. At least the lazy shifting 6 speed anyway. I will say the sonnax valvebody has made a difference but it still gets sloppy at moments. Mainly when it happens it gets caught between gears from red light to red light like it doesnt know what gear to be in. Either way I agree with running the engine hard and letting it work.
The 8 speed doesn't care ,it's twice the transmission the 5/6 RFE is. The 485 hp 6.4 cars get the same 8 speed,and even behind 485 hp the 8HP70 doesn't care how you drive itOnly problem with driving like you stole is the transmission doesnt like to be beat on. The engine always handles it just fine but trans not so much. At least the lazy shifting 6 speed anyway. I will say the sonnax valvebody has made a difference but it still gets sloppy at moments. Mainly when it happens it gets caught between gears from red light to red light like it doesnt know what gear to be in. Either way I agree with running the engine hard and letting it work.
Rub it in why don’t ya! LolThe 8 speed doesn't care ,it's twice the transmission the 5/6 RFE is. The 485 hp 6.4 cars get the same 8 speed,and even behind 485 hp the 8HP70 doesn't care how you drive it![]()
I still smile like a little kid when the tcm/ecm gods bless me with a shotgun crack upshiftThe 8 speed doesn't care ,it's twice the transmission the 5/6 RFE is. The 485 hp 6.4 cars get the same 8 speed,and even behind 485 hp the 8HP70 doesn't care how you drive it![]()
Yes it will. Put truck up on blocks, cover and never start up!!!and merely leaving the truck parked in the driveway will cure lifter/cam failures! LOL!![]()
1500s yes as they started mds in 06. 2500s didn't have it in 07 if I'm remembering right.Do the ‘07 model 5.7’s have the MDS system? I have approximately 230,000 miles on mine and haven’t had any problems with it since I bought it with about 150,000 miles on it. Fingers crossed.
Agreed!The 8 speed doesn't care ,it's twice the transmission the 5/6 RFE is. The 485 hp 6.4 cars get the same 8 speed,and even behind 485 hp the 8HP70 doesn't care how you drive it![]()
...and don't forget to spoil your truck with timely visits to the Spa, er carwash for it's beauty treatments!Agreed!
Best thing to ensure longevity and a happy transmission is to install the @caulk04 transmission cooler bypass valve (with the newly designed end plug, too), and perform regular transmission fluid and filter changes.
These transmissions enjoy spirited driving, but lack the happy helpfulness when they are really hot and especially have old fluid in them.
The engines, well, frequent spirited acceleration taking it past 5K rpm to get the VVT going, they really enjoy, too.
Best thing for a happy HEMI is to use quality synthetic oil, preferably with a better viscosity than what the OEM puts in as recommended, and a quality synthetic media oil filter. Coupled with timely OCI's as well.