Gladiator is not the only one suffering

[DAVECS2]

I am over on the Duranho forum now, and I just thought I would share an observation.

They have almost identical and as many engine complaints as we do over here. The latest iteration is giving Durango owners fits as well.

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[Charles 236]

I have just torn down a 3.6 upgraded Pentastar in a '22 Ram Promaster for a top end noise. I found a oddly worn intake camshaft on the right bank. One high lift lobe was worn down on each cylinder (two lobes for each cylinder). So cylinders 1, 3, and 5 each have lost one of two high lift lobes. So the upgrade doesn't seem to really help durability, but when you consider the number of Pentastar engines out there they are still relatively reliable engines.

 

[DAVECS2]

The high lift and cam phasing is an issue

 

[ShadowsPapa]

I have just torn down a 3.6 upgraded Pentastar in a '22 Ram Promaster for a top end noise. I found a oddly worn intake camshaft on the right bank. One high lift lobe was worn down on each cylinder (two lobes for each cylinder). So cylinders 1, 3, and 5 each have lost one of two high lift lobes. So the upgrade doesn't seem to really help durability, but when you consider the number of Pentastar engines out there they are still relatively reliable engines.

That's a very odd pattern of wear - one per cylinder worn? Why not both? Both lash adjusters, etc. for each cylinder come from the same source so can't blame oil supply for that one.

Consider these have been around since 2015 - the 2016 model year, yeah, there's problems but there's hundreds of thousands more with no problems.

 

[Charles 236]

That's a very odd pattern of wear - one per cylinder worn? Why not both? Both lash adjusters, etc. for each cylinder come from the same source so can't blame oil supply for that one.

Consider these have been around since 2015 - the 2016 model year, yeah, there's problems but there's hundreds of thousands more with no problems.

True about the odd pattern of wear on this particular one. I have seen both high lift lobes worm off for a single cylinder before, but this is odd indeed. As for oil issues causing the high lift lobes to wear, I am positive that it is not caused by oil system design flaws. There are hundreds of thousands, maybe millions, of these Upgraded Pentastar engines with no mechanical problems. I believe the problems are caused by metallurgy issues, such as heat treatment or inclusions in the camshaft itself.

 

[DAVECS2]

It's not oiling as in bad passages and stuff. There are two high lift solenoid actuators per cylinder and a new cam phaser for the intake cam that is different starting with the the VVL motor.

CAM position is controlled via calculated air charge. Aircharge is calculated using throttle position and a number of tables that complete coefficients for calculated aircharge based on engine displacement, intake volume, and throttle opening.

If you look at the cam tables, there are atheist 6 for most models. They all have an emissions dip off idle, they have a large shift for the moment VVL kicks in then there is a mid to high rpm shift for dynamic compression.

My Theory, with some anecdotal evidence mixed in, the VVL solenoids get dirty. It doesn't take much. Once dirty they no onger snap all the way shut as intended once above 2000-3200 rpm. They get leaky causing the high lift cam lobes on the followers to dither. This creates an un anticipated duty cycle for that metal on metal contact that was not designed for.

This malfunction could be captured by having in oil pressure sensor in the heads, to confirm VVL oil is off and on when it is suppose to be.

This issue is compounded by the new large displacement phaser on the intake cam, it shares oil volume with the front VVL Solenoid in each cylinder head. The phaser makes some large moves from 5000 to 3000 rpm. In order to execute those moves and be were the airflow model is expecting it to be the oil pressure need to be bang on. If you have a solenoid bypassing oil or the oil is just dirty and not filling the phaser as fast as it should it lags.

This lag gets flagged as many things as cam position is a feedback channel. Instead of using it for self correction, it logs nuisance faults about uncorrected airflow. This also cause momentary cylinder pressures that can cause detonation or just plain old misfire, as the afr and cylinder pressure is way off for those couple revolutions.

The reason I assumed my tunes to be pretty robust, is I was using cam positioning to waste gate air, for high cylinder pressure events, bad fuel or bad air. This works great when that system is working, when it's not..... well it gets complicated FAST.

 

[Charles 236]

There are two high lift actuators per cylinder head. The one in the valve cover controls high lift on the front cylinder, the rear actuator is at the upper rear corner of the head and controls the high lift on the rear two cylinders on that bank. In the Pentastar that I tore down yesterday, only one high lift lobe was damaged on each cylinder. Look at the rockers in this picture closely and you can see that every other rocker is damaged.

 

[DAVECS2]

So my

There are two high lift actuators per cylinder head. The one in the valve cover controls high lift on the front cylinder, the rear actuator is at the upper rear corner of the head and controls the high lift on the rear two cylinders on that bank. In the Pentastar that I tore down yesterday, only one high lift lobe was damaged on each cylinder. Look at the rockers in this picture closely and you can see that every other rocker is damaged.

So my take on that is the VVL solenoids were leaking. The lobes with wear, were the air purge for the excess cylinder pressure as they were no locked out all the way. Here are some pictures of when I lost a single lobe on cylinder 6, I was able to see it in the data. Sure enough the rear VVL Solenoid was all sludgy.

 

[FloridaMan655321]

Well this isn't the best thing to view
Curious, any possibility this being caused by excess engine turnover? Such as constant start/stop in traffic?
FYI, I'm kind of dumb, so apologies for any stupid questions

 

[Hootbro]

So my

So my take on that is the VVL solenoids were leaking. The lobes with wear, were the air purge for the excess cylinder pressure as they were no locked out all the way. Here are some pictures of when I lost a single lobe on cylinder 6, I was able to see it in the data. Sure enough the rear VVL Solenoid was all sludgy.

Was wondering what your thoughts are that caused the VVL solenoid to have sludge? Does oil grade play into it?

 

[ShadowsPapa]

My Theory, with some anecdotal evidence mixed in, the VVL solenoids get dirty. It doesn't take much. Once dirty they no onger snap all the way shut as intended once above 2000-3200 rpm. They get leaky causing the high lift cam lobes on the followers to dither. This creates an un anticipated duty cycle for that metal on metal contact that was not designed for.

That would explain BOTH for a cylinder, but not ONE wearing.
Plus - they are supposed to leak to keep the galleries and passages charged with oil. It's in the documentation that they keep the passages charged for fast change in modes.

Rear solenoid on left head handles cylinders 4 and 6 on that bank, rear solenoid on right head handles 3 and 5.
The front ones handle the front cylinder on their respective bank.

High lift mode is when the solenoid is closed.
Since the lock pin is either released (no/low oil pressure) to enable high lift mode, or retracted by oil pressure for low lift mode, there's really no in between.
So if there's pressure, it's in low lift, if there's no pressure, it's in high lift.
Leaking solenoid would cause the pin to stay retracted and keep it in low lift mode. But there's always oil flow to keep the passages charged. Too much only means it's in low lift mode.

Well this isn't the best thing to view
Curious, any possibility this being caused by excess engine turnover? Such as constant start/stop in traffic?
FYI, I'm kind of dumb, so apologies for any stupid questions

Not a thing to do with anything. Cranking the engine, hot starts, don't contribute to anything with oiling or valve train.

 

[DAVECS2]

That would explain BOTH for a cylinder, but not ONE wearing.
Plus - they are supposed to leak to keep the galleries and passages charged with oil. It's in the documentation that they keep the passages charged for fast change in modes.

Rear solenoid on left head handles cylinders 4 and 6 on that bank, rear solenoid on right head handles 3 and 5.
The front ones handle the front cylinder on their respective bank.

High lift mode is when the solenoid is closed.
Since the lock pin is either released (no/low oil pressure) to enable high lift mode, or retracted by oil pressure for low lift mode, there's really no in between.
So if there's pressure, it's in low lift, if there's no pressure, it's in high lift.
Leaking solenoid would cause the pin to stay retracted and keep it in low lift mode. But there's always oil flow to keep the passages charged. Too much only means it's in low lift mode.

Not a thing to do with anything. Cranking the engine, hot starts, don't contribute to anything with oiling or valve train.

In my mind it explains one lobe pretty good. How much oil pressure is to much? When does the high lift pin disengage? What happens if it engaged early? There's a control here with basically no controls on it. In my mind I had a low tolerance follower and it was getting engaged when it shouldn't and it failed first.

Shure leak some old, but leak too much and all the sudden you have a disease gage mental when you don't want one.

It never works good when it is all floppy

 

[ShadowsPapa]

Since it goes to low lift mode when there's oil pressure, it sounds more like it wasn't enough pressure to disengage the pin and let the high lift rocker loose.
Meaning - oil pressure was leaking off, not allowing the high lift to disengage.
A sludged solenoid that won't open - you are in high lift mode.
Maybe the thing was waffling and not making up it's mind like it sounds you are suggesting is possible.
Just pop some Isky cams in it and keep those valves open high and long and move on.

 

[DAVECS2]

Since it goes to low lift mode when there's oil pressure, it sounds more like it wasn't enough pressure to disengage the pin and let the high lift rocker loose.
Meaning - oil pressure was leaking off, not allowing the high lift to disengage.
A sludged solenoid that won't open - you are in high lift mode.
Maybe the thing was waffling and not making up it's mind like it sounds you are suggesting is possible.
Just pop some Isky cams in it and keep those valves open high and long and move on.

Isky cams would be a 2fer. Superior metallurgy and better performance. If any one needs cam stuff I have two engines worth.

 

[Uparms]

Isky cams would be a 2fer. Superior metallurgy and better performance. If any one needs cam stuff I have two engines worth.

Tell us more. Do yuu have part nubers for ISKY and the rest of the cam job if ( IF) someone wanted to do it themselves?.

Furthermore, how difficult and unintrusive would it be to at least get down to the inspection and noninterference/non-disturbance of parts phase? Note pad and an iPhone, it might be worth and fun it to get in and take a look?

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