The good and the bad of a roots supercharger.

[CerOf]

Atropine! Atropine! Charge to 300!!!

Totaly respect for you Dave. I wouldn’t know where to even start in diagnosing something like that.

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[ShadowsPapa]

Peoria, we have a problem!

Sad that anyone would equate or even try to connect any valve train issues to your mods. If you were over-revving and smacking the valve spring coils against each other, or getting into valve float........... ok but geesh, you don't need 6,000+ RPM to get your power.

Hmmm I think BEER is the answer!

Ah, alcohol injection! Worth a try.

 

[SteveInOrlando]

Ok, your Knock reduction is crazy high there. I would be freakin out!

Do you know when they put that rocker change into production? The difference in those parts is pretty dramatic! I am wondering if that should be a preventative change for those of us on the old style.

I know several people that have had this problem with 2020 models.

 

[DAVECS1]

Any JL or JT 3.6L will have the new style varialble lift cam and rockers.

I probably went a bit crazy posting data, but I am pretty stoked how well my engine is protected. I knew I had put it in there, but to see it work so well, I was quite pleased. I will quit trying to break my own arm.

As for the timing reduction, I have seen trucks with injector and coil problems take way more timing than that, before my tune is installed. It is actually qhat helped me with these strategies. Look at the intake charge, at that boost level. The fuel goes way rich, and the cam position moves on the exhaust to release all the pressure, and it is 100 degrees or less, on the intake charge. Not gonna tempt fate but at those temps and pressures , the conditions are pretty safe. Worse case scenario the oil gets some fuel in it and the plugs take a beating. Way better than lunching a ring land.

I got most my parts in, so I am hoping to dive in tommorow.

My wife took my jeep today with all the limits on it, and she did not even notice anything was wrong. She actually commented on how smooth and quiet it was and she drives a 4xe!!!

It was running really well today, I don't think my rocker is totally messed up, but I don't wanna take chances.

 

[DAVECS1]

Well look what I just found on Facebook. It is happening folks, and the sad thing is it is almost undetectable until the damage is done. If you are having a rattle you need to have misfires logged on your Engine for each individual cylinder when ot is revved beyon 3500 rpm at 50-75 percent load.

Here is what I found. There is a variable lift oil solenoid in the front of the valve cover. At Idle to 2800 rpm it is off and supplies oil to the number 1 intake rocker. Once you get over 2800 RPM it turns off and the rocker is spring loaded to go to full lift. The problem I had, is the ECM turned it off but the oil kept flowing so the high lift lobe was never getting activated and I imagine has done this to my cam. There is no diagnostic or sensing measure for this failure. The 3 and 5 cylinders are on a different solenoid.

So rocker problems as they where in the old 3.6 may be solved, but this is a whole new level of mess.?

 

[jsalbre]

What are we looking for in those pics, Dave? I don’t see anything with chunks taken out, no shards or shavings, and no major scoring, so I can’t see where the problem is. Enlighten us less educated Neanderthals please!

 

[ShadowsPapa]

What are we looking for in those pics, Dave? I don’t see anything with chunks taken out, no shards or shavings, and no major scoring, so I can’t see where the problem is. Enlighten us less educated Neanderthals please!

No major scoring? Maybe the problem is you need to open the pic on a computer and not a phone? Seriously, the lobe I've pointed to with red arrow is toast, worn badly and some scoring showing it was under a lot of pressure with no lube, or had crazy forces acting on it (like a bound valve spring. This used to happen when performance builders used high-lift cams but didn't allow for the spring compression and the coils bound up)

Here is a pic I have from the web showing similar, but worse, damage - in both pics the cam lobes are toast - the upper is smoother but note the sides are what the lobe should look like, the middle is gone.

 

[DAVECS1]

Look at the top righthand highlift cam lobe.

 

[DAVECS1]

Man your freaking me out SP, cause in these pictures it does not look like it is relegated to one cam lobe. Yours looks to be on the opposite side of the engine!!

 

[ShadowsPapa]

Man your freaking me out SP, cause in these pictures it does not look like it is relegated to one cam lobe. Yours looks to be on the opposite side of the engine!!

Luckily that is not mine.
I was looking for examples of modern 3.6 cam lobe damage.
It took only seconds with Google and found that example - and yes, I thought -HOLY XXXX batman! I'd better pay really close attention to the sounds mine makes!
I believe I was looking for such damage as someone said it was ok to replace the cams and not change the oil.

I've done enough engine work over the years - granted on old-school engines - but I still recognize worn cams at 100 yards LOL

 

[jsalbre]

No major scoring? Maybe the problem is you need to open the pic on a computer and not a phone? Seriously, the lobe I've pointed to with red arrow is toast, worn badly and some scoring showing it was under a lot of pressure with no lube, or had crazy forces acting on it (like a bound valve spring. This used to happen when performance builders used high-lift cams but didn't allow for the spring compression and the coils bound up)

Here is a pic I have from the web showing similar, but worse, damage - in both pics the cam lobes are toast - the upper is smoother but note the sides are what the lobe should look like, the middle is gone.

Oh man, my eyes skipped right over that. I wasn’t looking for damage that extreme. That’s not scoring, that’s shaved clean down. I’d imagine that thing is nearly circular at this point.

So while there’s no direct indicator to watch for this, I take it that logging for misfires and coming up clean is a good sign that you *aren’t* suffering from the problem?

 

[DAVECS1]

Luckily that is not mine.
I was looking for examples of modern 3.6 cam lobe damage.
It took only seconds with Google and found that example - and yes, I thought -HOLY XXXX batman! I'd better pay really close attention to the sounds mine makes!
I believe I was looking for such damage as someone said it was ok to replace the cams and not change the oil.

The kicker is, it is almost undetectable, until you go to really use your engine and then it shows up as misfire, with a rattle. Yeah, that won't get misdiagnosed at all!!!!

 

[NachoRuby]

I'm getting a rattle occasionally, but no misfires, nothing that shows up often enough to log, or reproduce at the dealership. But it sounds like it could be this. Hopefully it gets worse (weird thing to say) before warranty ends.

 

[DAVECS1]

I'm getting a rattle occasionally, but no misfires, nothing that shows up often enough to log, or reproduce at the dealership. But it sounds like it could be this. Hopefully it gets worse (weird thing to say) before warranty ends.

If it was me I would try to insist the dealership pop the valve covers, and replace the VVL solenoids. The noise is probably the VVL solenoids not working, and when you hear it, that is metal on metal hammering contact to your cam, at high rpm. Chances are one or more of your 4 VVL solenoids is malfunctioning intermittently and you hear it. When it completely goes it will finish wiping out parts.

If I was an argiuing man, this is definitely recall, litigation worthy failure mode stuff

 

[ShadowsPapa]

The kicker is, it is almost undetectable, until you go to really use your engine and then it shows up as misfire, with a rattle. Yeah, that won't get misdiagnosed at all!!!!

I believe what you are saying is that this sneaks up on you............ they can tolerate a lot of wear and not "misfire" - but I'd bet the trim tables would have to be off? I mean, if you aren't letting in the air, or letting out the exhaust, aren't you going to see the thing trying to compensate by changing the fuel going in? Intake lobe badly worn, valve not opening like it should, less air going in so the normal injector spray would be too much for the air that did get in - and the PCM would try to trim it back?
Time for another coffee - maybe it doesn't work like that - but if you can't get the exhaust out (in cases of worn exhaust lobes) or in these cases, the intake valve isn't opening and letting enough air in, won't that trigger a mixture change? The O2 sensor readings would have to be off.
On old engines if there was a badly worn lobe or the lifter caved, it would pop - BANG - back through the carburetor.

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