Thanks Joe for showing us the bad news. When you are in the fold of the hemi circus, you realize how prevelant this is, I can't even tell you how many hemi cam lobs I have seen like this. You talk to a bunch of randon hemi owners for a period of 5 years, and it just so happens that 10% of them end up this way? You watch the online mechanics like Motor City Mechanic and many others that see Rams and you see how they talk about the hemi cam issues. It is a very prevelant issue in the hemi world, more common then anyone knows. I was watching this one when they brought a ram in for this issue but the guy had all 3 of his bays full of 3 trucks with the same issue. Sometimes they can't get the cam out = total loss. Do you have any idea how many times I have heard cams or lifters on backorder? Why do you suppose that is? I think if every guy that had this happen put the work you put in, we would have a better handle of this thing. Thanks again, I have some guys reading this thread to see if they have anything to add that may be helpful. In the end you and OK likely helped them understand about the issue more then they have to contribute back.
Thanks for the complement. And I do hope that someone that you might know with extensive experience in repairing the Hemi can offer some solutions. My wife is getting ticked off at me because I have not yet begun to fix her truck; it's tore down but not yet repaired. She doesn't understand the complexities involved. Sure I could buy stock parts (assuming I could even acquire them in sufficient time) and get the darn thing running again. But all it will do is happen again. Heck my son debated with me on this and asked, "Why not just go to a junk yard and pull parts from another Hemi"? LOL I explained to him that:
1. Junk yards will not usually sell you engine parts (internal that is); they prefer to sell the entire engine
2. Installing a similar MDS style engine would only lead to the same problem
It's my strongest opinion that the primary reason why the exact cause cannot be found on the web is because of the large amount of censorship, misinformation, and disinformation flooding the web by pro-Hemi folks who are either working as Chrysler trolls, or just trolls in general, flooding the net with false failure rates (claiming the number of failures is low based on the total number of produced Hemi's), pointing the finger at lifters, and my favorite one is blaming the driver for long idle times or inadequate oil changes. These excuses to cast blame away from Chrysler engineers is laughable to say the least. Claiming low failure rate compared to a huge back log of stock lifters is contradictory, to say the least. LOL
I've examined this engine inside and out, not that I'm perfect, but I consider myself to be a very good mechanic. I work on all kinds of different machines and it doesn't take a rocket scientist to figure out what's going on here. So here is my belief on the cause of the problem.
I believe the primary problem is insufficient oil volume due to the EPA's CAFE standards on fuel efficiency which forced automotive engineers to find every way possible to safe a few micro-gallons of fuel per 10 feet of driving. LOL I'm exaggerating of course. Some claim that the problem happens on non-MDS vehicles, and siting that the reason for lower failures with non-MDS systems has to do with lower ownership of non MDS systems. This to me, while difficult to prove, is untrue. I see more Challengers and Chargers on the road than I do RAM's. Yet most of the vehicles I see at the local dealership having engine lifter/camshaft repairs being done to them are RAMS. The few non-MDS Hemi's that are failing are likely due to stress from owners of these fast machines have a difficult time keeping their food off the gas pedal. I don't know how many Charger owners I see romping their pedals and spinning tires. And logically, anytime you build a high performance engine using low performance parts, you're going to see these kinds of failures. Thus, it is my personal opinion that the low lifter failure rates of the non-MDS Hemi's are from abuse. But for the RAMS, I firmly believe it is directly tied to insufficient lubrication. And the oil starvation is exacerbated by the MDS itself. Oil pressure is required during the entire time the MDS is on operation to keep the MDS lifters from locking. Even though MDS only does this during cruising speeds and at higher RPM's, the current chain-driven oil pumps, in my opinion, are not putting out enough pressure.
The primary culprit with regards to oil starvation is the use of non-weighted engine oil. During hot days and long idle times, coupled with a very weak oil pump, insufficient oil volume exists, thereby leading to over heated needle bearings in what might also be poorly designed lifters. Another factor to consider are the lifters (more specifically MDS lifters) getting stuck and not allowing the push rods to sink into the lifter as they are supposed to. This might be evidenced by the heavy damage seen atop of the valve spring caps denoting heavy wear from the extra forces being applied.
From my engine, the only side that suffered both cam and lifter failure is Bank 2 (passenger side). The drive side denote zero indications of abnormal wear. The differences between Bank 1 and Bank 2 after careful examination were this:
1. All of the lifters appeared to be well lubricated on Bank 1 (driver side).
2. Most lifters on Bank 2 showed abnormal wear patters, i.e. severely worn rollers, rollers worn at a taper pattern, cam lobes being ground down, and one lifter completely destroyed #8).
3. 2 of the MDS and 1 non-MDS lifter were completely frozen, and did not allow the push rods to spring/pump atop of the lifter as they are designed to do. This did not happen on Bank 1.
So based on my findings, to me the problem was caused by lack of lubrication on Bank 2, likely caused by the locked/failed lifters which led to too much oil for the MDS lifters, and not enough oil for the non-MDS lifters. There will be those who do not agree, and that is okay. Whether or not their motives for objection are genuinely true, or simply misguided. But this one fact remains. Chrysler has had several decades of producing horrible unreliable vehicles even as far back as the 1980's. This is why many of us with lesser incomes might be inclined to buy a Dodge vehicle; especially poverty stricken people with poor credit. So there really is no incentive for Chrysler to build a high quality vehicle. And as I've stated before, I've owned a total of 4 Dodge vehicles, and 3 of the 4 all crapped out below or slightly above 100K miles, despite religious upkeep and routine maintenance. It's gotten to the point now that no matter how much you baby your Dodge, the [censored] thing is going to break on you, whether you like it or not. Some do last longer than 300K; I've seen it. But most do not seem to make it. Stratus sucks, Neon's were horrible, Intrepids catching fire, Durango's killing occupants from failed ball joints while traveling at highway speeds, 2.7 liter pump failures destroying the chain and the coolant systems, 2.0 and 2.4 liters losing head gaskets and oil, 3.1 liters also losing oil, and now Hemi's losing valve seats (earlier Hemi's) and modern Hemi's losing lifters and cams.
While other vehicle manufacturers have had their share of problems, NONE and I do mean NONE can compare to the large history of failures Chrysler continues to have. Thus in my strongest opinion, and anyone can take this to the bank, Chrysler needs to close down and let them fade away into history. Ford has had their fair share of problems, but they seem to have bounced back with the eco-boost and the fusion. GM has held strong for a while, until they had initial problems with the LS engine designs (piston slap), and now they too are facing problems with DoD (Displacement on Demand). Hmmmm? Both GM and Chrysler having issues with their cylinder on demand technology...Now if that doesn't leave everyone at the logical conclusion as to the cause of the problem, I do not know what else will.
FACT: Displacement on Demand or MDS (what ever you want to call it) is a complete failure. It failed in the 1920's with the early model Ford's; it failed in the 1980's when cadillac tried it, and now it is failing again.
Sorry for the long post. I'm frustrated to say the least, and Chrysler has a huge FU headed their way. LOL