Engine Noise - Clatter at 3,000 RPM

[syreeves]

About a month ago i noticed a distinct relatively high pitched and fast clatter or chatter coming from my engine. From the driver's seat it definitely sounds like it is coming from the far right side of the engine. I was able to determine that the sound comes on just below 3,000rpm and is present till at least 3,200rpm. I can't tell if it fades away at higher engine speets because at higher engine/road speed there is too much other noise. Here is all the info I think would be remotely relevant:

I have a 2021 JT Rubicon, 3.6L gas engine with the 6MT, 35s and mopar 2 inch lift. I have just over 21K miles and have performed dealership oil changes at 5K, 12K and 19K miles. Except for the wheels and suspension lift everything related to the drivetrain is bone stock e.g. 4.10 gears etc. The engine makes this sound in in 2H and 4H. I do not think it is related to the transmission- the sound is definitely tied to engine speed.

The best way for me to generate the sound is in 2nd gear which for me is about 25mph. At that speed the tire noise and wind noise are still low enough to catch the sound. I can faintly hear the same noise in 3rd but at that engine speed in 3rd I'm doing about 40mph and the wind noise starts to drown out the clatter.

I have a hard top in good condition but no head liners etc.

Do you experience any kind of noise that is like a clatter or chatter like this? Is it normal? I may take it to the dealership because I can reproduce the noise now but it tends to be a bit louder (i think) when the engine is colder (oil temp less than 150F for me which is about 15 mins of driving in 0F weather here in MN).

Any thoughts would be appreciated.

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[DocMike]

What octane are you running?

 

[Gumidaka]

Have a read through here, sounds like same issue many have had.

rattle-from-engine-when-accelerating-sounds-like-keys.36157

 

[syreeves]

What octane are you running?

87 like the manual says... i thought about knocking but it doesn't sound like that... also the clatter is there even when I am off the gas eg decelerating... thanks!

 

[syreeves]

Have a read through here, sounds like same issue many have had.

rattle-from-engine-when-accelerating-sounds-like-keys.36157

Thank you. I am reading now!

 

[DocMike]

Ok. Mine sounded like a diesel under load. Like it was lugging. I upped my octane and it went away.

87 like the manual says... i thought about knocking but it doesn't sound like that... also the clatter is there even when I am off the gas eg decelerating... thanks!

 

[Aonarch]

87 is for marketing.

These engines really should be running 91-93. The compression is too high for 87.

This is dumb. Higher octane gas in these engines will fix the pinging.

 

[syreeves]

87 is for marketing.

These engines really should be running 91-93. The compression is too high for 87.

This is dumb. Higher octane gas in these engines will fix the pinging.

Thanks. Pretty sure it is not pinging. On down hills when I am off the gas pedal I still get the clattering sound above 3K RPM. I'm beginning to think I have something loose that is just vibrating...

 

[DAVECS1]

Well I have dug into this issue, I believe, as I am getting the same noise now at 28k. Sounds like a faint rocker rattle around 3000 rpm.

My first reaction was OH No! The dreaded rocker arm failure in the 3.6L. I actually ordered all new followers and lifters.

Then I started thinking this engine has variable lift and the rockers are vastly different and have lockpin passages for low/high valve lift. There is a solenoid that directs oil pressure to the rocker for low valve lift, this usually is on below 3000 rpm. As your load and rpm increases the solenoid shuts of the oil around 3000 and a spring engages the high rpm lobe on the rocker.

I know the engagement points cause I have tuned them in my software.

Looking at the design I don't think these rockers can hurt the cam like the old ones.

I changes my oil and sent it off for analysis, my magnets picked up fine particles but nothing shocking to the naked eye. No glitter was present.

My current guess is the VVL solenoid is not sealing shut when it turns off and there is oul getting past and it is messing qith the lock pin and keeping the rocker from going to solid full lift.

Another scenario is the spring for full lift actuation in one of the rockers is bad and the lifter flops around until high rpm throws everything into place.

 

[syreeves]

I found the problem. Bad rocker ground my camshaft down.

See: Star Case Number: S1309000016 which I found here:
chrome-extension://efaidnbmnnnibpcajpcglclefindmkaj/viewer.html?pdfurl=https%3A%2F%2Ff01.justanswer.com%2Fdodgetech77%2Fd05b3bac-6fb9-4bc5-b2b0-cbb8a3172e0c_3.6%2Bissue.pdf&clen=169012&chunk=true

And also

 

[DAVECS1]

I swapped my control solenoid on the passenger side and no improvement. I am worried a rocker is broke. I have new ones ordered.

 

[syreeves]

As noted by my local dealer - when the rocker went bad it ground up the camshaft. This is a known issue since this engine came out in 2011. Best of luck to you. Sorry

 

[DAVECS1]

This camshaft is different than the 2011 model. It has variable lift. Though it is looking like a bad rocker at this point. I bought all new lifters and followers and now a new intake camshaft. Might have to start running Schafer's. All this talk about oil here is were it shows itself, when your valvetrain is sketchy

 

[Hootbro]

This camshaft is different than the 2011 model. It has variable lift. Though it is looking like a bad rocker at this point. I bought all new lifters and followers and now a new intake camshaft. Might have to start running Schafer's. All this talk about oil here is were it shows itself, when your valvetrain is sketchy

Just my 2 cents from following the Pentastar rocker arm issue for a few years is that basically past mid 2014 or so when they addressed the rocker arm with a redesigned larger hole in the cup for better oil flow, that took care most of the needle bearing failure issues. After that to include the new upgrade Pentastar in our Gladiator, the main problem with rocker arm failures and cam lobe wiping is due to bad human assembly quality control and not so much a bad design.

 

[DAVECS1]

Yeah I just posted in my other thread. It is a completely different design. It will be interesting what I find when I pull the valve covers.

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