The good and the bad of a roots supercharger.

[DC3]

Did you find the wrong lifters on one side as well?

Frankly, I don't love the looks of the low lift roller lobes either, such as where I marked in red.

And, like asked already, were the correct lash adjusters installed for the intake?

(Front solenoids control the front cylinder on each bank, rear head mounted solenoids control the rear two cylinders on each bank. )

I honestly don't think the wrong lifters are installed on the intake side. I believe the intake lifters (lash adjusters) have been revised, and the new design's top hat is a bit different. The intake lifters differ dramatically from the exhaust lifters in height and design.

I am really puzzled by the failure because of the driver's side wear pattern. The intake lobe failure does not align with the solenoid/lifter relationships. I wonder if this is a failure of the intake rockers not kicking out of high lift?

Do I misunderstand the lifter design and the belief that the intake lifters are wrong?


Exhaust vs Intake lifter (both removed from head)

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[ShadowsPapa]

I think you have it right. The intake lash adjuster has two oil ports. And yes, if it stays in high lift mode due to lack of oil pressure to shove the pin back, then it's running high lift all the time.
Still disheartening because these should be able to run in that mode without any destruction or abnormal wear.

 

[DAVECS1]

That head on the follower definitely makes a difference. My friend who works at chrysler definitely was concerned with that follower with the grooved head being in my engine.

 

[DAVECS1]

I am doing an install right now on an engine that has 40k and it has wear and the vvL solenoids were dirty and jammed up.

 

[DC3]

It

I think you have it right. The intake lash adjuster has two oil ports. And yes, if it stays in high lift mode due to lack of oil pressure to shove the pin back, then it's running high lift all the time.
Still disheartening because these should be able to run in that mode without any destruction or abnormal wear.

It would be interesting to know their design criteria for the service life of the cams and expected time above ~2,800 rpm (high lift mode). If our motors are stuck in high lift more 100% of the time and we have 30k miles, that could be the same as 300k miles on the motor assuming high lift @10% of the time, for example.

If this were a design flaw, you'd think we'd be seeing 3.6 JL wranglers dropping like flies.... maybe the issue isn't accentuated enough with naturally aspirated engines? I attached an interesting technical document explaining the VVL in high lift mode and corresponding diagnostics. I have have only skimmed the document. This is from Alldata DIY, I don't maintain an annual Mopar tech subscription but may just get month subscription to review their tech literature on the topic.

 

[DAVECS1]

I hVe probably helped at least 250 ppl since I made my first post. 40% of those being JLs.

 

[ShadowsPapa]

It

It would be interesting to know their design criteria for the service life of the cams and expected time above ~2,800 rpm (high lift mode). If our motors are stuck in high lift more 100% of the time and we have 30k miles, that could be the same as 300k miles on the motor assuming high lift @10% of the time, for example.

If this were a design flaw, you'd think we'd be seeing 3.6 JL wranglers dropping like flies.... maybe the issue isn't accentuated enough with naturally aspirated engines? I attached an interesting technical document explaining the VVL in high lift mode and corresponding diagnostics. I have have only skimmed the document. This is from Alldata DIY, I don't maintain an annual Mopar tech subscription but may just get month subscription to review their tech literature on the topic.

There's some good added information in there - especially about the symptoms and so on.

 

[ShadowsPapa]

I find this bit especially interesting. I should have known or seen this already because it's totally logical that they would do this - you'd not let one cylinder be in one mode when the others are not and cause a serious imbalance so if one or more are at fault - stuck in high lift, then default to all high lift.
But that sort of contradicts the physical findings I've see so often where it was just ONE side that had extreme wear - the right bank.
Why the right bank would be toast but the left not? If 1 or 2 on the right side stick in high lift, the PCM puts them all in high lift, so if it's a matter of running in high lift mode causing wear - no, I don't see that. Makes no real sense.
If the wrong lash adjusters were used, those would be in high lift - the PCM would kick all into high lift meaning there should be trashed lobes on the left, so this sort of contradicts the idea that running in high lift mode is the trouble, IMO -
Besides, there's a lot of engines running flat tappet-like designs and rubbing followers or rocker arms.

So right side stuck in high because of incorrect lash adjusters or other faults - all go into high lift, then why are only the right side shot in many cases we've seen here (present company excluded as there's problems on the left here)

My gut is pointing to more than one cause or trigger for the damage being seen on these engines.

 

[DAVECS1]

The JL I am working on know had so much dirt in the solenoids

 

[jsalbre]

Something (several somethings really) just doesn’t make sense here.

There are some consistencies (worn cam profiles) and a lot of inconsistencies (varying levels of wear, different/incorrect components installed, one side or both sides worn) between different cases.

I’m wondering if the cams themselves weren’t manufactured properly. Maybe a bad heat treat or wrong metallurgy?

 

[ShadowsPapa]

Something (several somethings really) just doesn’t make sense here.

There are some consistencies (worn cam profiles) and a lot of inconsistencies (varying levels of wear, different/incorrect components installed, one side or both sides worn) between different cases.

I’m wondering if the cams themselves weren’t manufactured properly. Maybe a bad heat treat or wrong metallurgy?

That touches on my "wonderings".
Example - right bank has incorrect lash adjusters installed. Intake valves on right bank (odd numbered cylinders) never ever go to low lift mode because there's 0 oil pressure to force the plunger back. It requires 20 psi+ to push the pin back and allow low lift mode. Exhaust lash adjusters have no oil passage so 1, 3 and 5 never, from day one, never get low lift mode.
Result - PCM does its test to determine if any followers are stuck in high lift mode. IF it finds even 1 stuck in high lift, it defaults all of the rest to high lift mode.
And yet - only the right bank cams were impacted (at least in most cases)
If all 12 intake rockers/followers are forced to high lift because the PCM determined some were high lift, AND if the cause was "always being in high lift mode" then all should be scored or at least worn.

If the reason is being on high lift mode for 20,000 miles, then why only the right bank (in most cases)?
And why did FCA have a TSB stating that the right bank intake cams should be replaced and the PCM flashed after the right bank cam replacement? What was wrong with those right bank cams that FCA said they should be replaced if A, B or C were true on their TSB?

I now believe there is more than one "root cause" for intake cam failures.

This being true - it's very telling -

If any Rocker Arm is detected as being stuck in High Lift Mode, the in-¦eld diagnostic (by the PCM)
will fail and quickly default to commanding all of the Rocker Arms to High Lift mode.
The engine will have some roughness and mis¦re may be felt.
A single Rocker Arm stuck in high lift mode typically mis¦res at idle.
The PCM will illuminate the MIL on the second trip.

 

[21Moja]

I have a strange question but I think some of us who are at the beginning of modding our JTs would find this relevant...If I want to go to 37s, looking at regearing and doing ball joints at the same time. Im wondering if this moves towards a warranty item will all the work done screw me on the warranty work? If this becomes a bigger found issue I have little doubt they will be looking for any reason to deny the work...

 

[ShadowsPapa]

I have a strange question but I think some of us who are at the beginning of modding our JTs would find this relevant...If I want to go to 37s, looking at regearing and doing ball joints at the same time. Im wondering if this moves towards a warranty item will all the work done screw me on the warranty work? If this becomes a bigger found issue I have little doubt they will be looking for any reason to deny the work...

They can't. Tires and ball joints are totally unrelated to engine wear like this.
They might fuss if you go in with death wobble, a pull, or any instability, etc. because honestly, taller tires introduce a whole slew of other things into the steering and suspension, having effects no one ever bothers to think about (because they look cool) but regearing and tires can't cause engine warranty issues. The fact you are thinking of gears along with the tire size change means you are likely not changing the engine RPM much on the road.
IF a dealer balks - don't push it, go to a different dealer. You are protected.

 

[21Moja]

They can't. Tires and ball joints are totally unrelated to engine wear like this.
They might fuss if you go in with death wobble, a pull, or any instability, etc. because honestly, taller tires introduce a whole slew of other things into the steering and suspension, having effects no one ever bothers to think about (because they look cool) but regearing and tires can't cause engine warranty issues. The fact you are thinking of gears along with the tire size change means you are likely not changing the engine RPM much on the road.
IF a dealer balks - don't push it, go to a different dealer. You are protected.

Cool, thanks...I think the gear swap was the biggest key...I have known guys in the past TJ and JK, that had serious issues with anything warranty related when the pumpkin was cracked open...Almost like a gear swap has moved the planet out of axis.

 

[ShadowsPapa]

Cool, thanks...I think the gear swap was the biggest key...I have known guys in the past TJ and JK, that had serious issues with anything warranty related when the pumpkin was cracked open...Almost like a gear swap has moved the planet out of axis.

LOL - yeah, once that cover is popped loose, the laws of the whole universe change, and you enter a quantum world.

Ironically, I've had a local dealer cover stuff that wasn't even Jeep's fault and I told them so going in.

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