I've always worked on Chevy engines and now that I've built (2) 2004 Ram 5.7 Hemi engines, I find the valvetrain oil flow path interesting and a bit complicated.
I couldn't find this information anywhere else online, so figured I'd add it here for reference for anyone interested.
For some odd reason, oil info is hard to find for these G3s,
I personally think it's one of the better thought out systems out there today....
The oiling tricks are harder to find, not that there is a lot of them, not like the old school Mopar’s where every engine family has its special tricks to survive.
The Top end is feed separately (so to speak) but the lifters are feed at the same time, the passage that comes up from the main galley, between 1/3 2/4 5/7 6/8 feeds the MDS(and NON MDS) off of the passage that goes to the heads. Each set of 4 lifters is feed by it’s own passage and drains back thru lifter bore clearance.
The passage to the MDS solenoids is very small and hard to find,
Oil comes up from the pump hits the 1st main and then main oil galley above the crank and below the cam tunnel, feeds Cam Bearing #1 travels down the main galley feeds the 1st Top end passages and the 2nd Main and cam bearing, so on and so forth.
One of the things That I like about these engines is the lifters banks are separated in to 2 separate sets of 4 .
(Oil trick if you want to block off oil to the lifters you just block off the passage in the MDS hole where it taps into the head feeds)
Another thing I really like about these G3s is you can modify the oil system to feed more oil to the top end without affecting the mains and cam bearings.
Also if you have a catastrophic lifter failure it’s not going to drop oil pressure and wreck Main and rod bearings.
Oil from the Rocker's and pushrods feed the rocker cup, kind of over kill if you ask me but I was told it was designed that way to have a secondary source of oil to the lifters to insure that the bore was lubricated if there was an issue with the MDS solenoid
Now if these bright engineers didn’t straight cross drilled the 03-08 cranks they way they did there would be no high RPM oil issue.
Oil from the Rocker's and pushrods feed the rocker cup, kind of over kill if you ask me but I was told it was designed that way to have a secondary source of oil to the lifters to insure that the bore was lubricated if there was an issue with the MDS solenoid.
My engines are 2004 non-MDS and the only source of oil to the inside of the lifters is from the pushrods above.
Which is what led me yesterday to cut a lifter in half to begin figuring out how the oil flows through the drivetrain.
Do all 16 lifters in the MDS engines receive oil from the side of the lifter or only 8?
In the pictures I've seen online of the MDS engines it appears that for each group of 4 lifters, only 2 have holes on the side.
The only oil related trick I've heard of is the clocking the rear cam bearing orifice to 5 o'clock with the thought it is a lower pressure area at that point allowing oil to enter the bearing surface with greater flow.
Here's an 04 with the plug removed(crappy photo) , at the bottom you can see the oil passage , it's a small hole I know.
I have a few 03/04 section block photo's I'll try and dig one up be the end of the week.
I've cut up and sectioned about 20 some odd 03-2016s 5.7s 6.1s 6.2s 6.4s I have cross sections, Oil passages, bore thickness(2nd Photo) Drain backs, Main oil Galley, water jackets , you name the section and reference point of a G3 hemi And I'm 99% positive I have it , if not I have a bunch of scrap blocks I can get it from.