Intake Cam Failures - Materials, Design, or both?

[bmpcamry09]

I’ve talked about this in my other threads, but I want to start a fresh one as those are super crowded. This is in an effort to educate people and make the JL community more aware of what I believe is the root issue

I’d like opinions on what people think is causing this. Is it materials? Design? Tuning? A combo of all 3?

I think it could be all 3, with tuning and design at the top of the list

Cam failure…..EVERYONE keeps talking about it. Everyone gets it fixed. Then they all fail again. Something I find unique is on nearly every failure people post about, there is a common theme: the failure is on the intake cam, and the cam damage is on the center cam lobes.

Some people make it 150,000 plus without issue. Some people make it 5000 miles.

This is different than the cam/lifter wear on the first gen 3.6 from the JK days. I mean, yes, crap materials, but I’m not convinced the PUG pentastar 3.6 failures are only from crap materials.

If you guys look into the Variable Valve Lift system on these PUG 3.6 engines (2018 and newer) and look at its design and use, you’ll see why these could be having so many cam and lifter failures. At least, this is my take on it. Mind you I’ve probably done more research and study on this than the average Joe.

Almost every camshaft/lifter failure I have seen on these newer engines post 2018 is the center lobe (high lift) and not the two outer lobes (low lift). The two smaller outer lobes of the cam shaft are what are used 80 percent of the time the engine is running. Most of the damages on these newer engines are the big center lobe/high lift lobe.

The high lift side doesn’t use a traditional roller/rocker. It uses a pin and its engagement is a very abrupt event. Ironically, when I developed tuning on these I actually discovered that “high lift” mode isn’t even used for high power and that high lift is used more like a way to add airflow for emissions purposes at lower load. Think of the engagement points as being very similar to when Eco/MDS/V4 mode kicks in on the hemis and GM V8 engines. The people who have been saying for years high lift kicks in over 2800 RPM are straight up wrong.

I made a whole video about this debacle, and I am confident this hi lift system is partially causing premature cam wear, in addition to less than quality materials.





You’ll probably never see a formal fix from Jeep in the USA for this because it will effect emissions and they won’t jump through the hoops for that, even though everyone running my fix for this is reporting same or even better MPG.

I don’t have any long term proof yet guys that this is the issue. But with all the years I’ve been messing around with these engines and the amount of research and looking into them I’ve done, it just makes sense to me. These advanced emissions management systems hurt more things than do good across all manufacturers.

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[mwilk012]

It’s disproportionately bank 1. I don’t want to say “always” because only fools speak in absolutes, but there is clearly a problem with bank 1 intake cams. The center high lift love using the sliding shoe instead of a roller rocker is part of the problem, but clearly not enough.

 

[Remorseless]

I don’t want to say “always” because only fools speak in absolutes

But this is an absolute...

 

[azjl#3]

My gut feeling, poor engineering design and poor metallurgy control or systems control issues.

You know they tested their design, right, i mean to the 250,000 miles point to detect flaws. It passed.

That leaves the metallurgy issue, i think they lost control of the process by outsourcing. Sure the first million or so, then they stopped checking the lots.

However, they could have easily spent another $40 per engine, used roller rockers and solved all this, and made a 150,000 mile engine.

But, $40 per, at 16 mil built, thats like 640 million, real cash they saved.

 

[bmpcamry09]

It does seem like bank 1 is the most common side. I have a feeling the 3.6 is on its way out over the next 5 years. Doubt they change anything

 

[Matt878]

Bank 1 …13,000 miles. Switched to Amsoil Signature 5w-30 no issues since

 

[bmpcamry09]

Bank 1 …13,000 miles. Switched to Amsoil Signature 5w-30 no issues since

I'm a Amsoil fan boy and have spent loads of money with them over, but I've really been loving the newer products from Valvoline. Restore and Protect in my 220,000 mile 5th Gen 4Runner has been wonderful and my 25 JL 3.6 seems to love the Advanced Synthetic 5W30. Was thinking about trying Amsoil SS 0W30 on the next one.

 

[Matt878]

I'm a Amsoil fan boy and have spent loads of money with them over, but I've really been loving the newer products from Valvoline. Restore and Protect in my 220,000 mile 5th Gen 4Runner has been wonderful and my 25 JL 3.6 seems to love the Advanced Synthetic 5W30. Was thinking about trying Amsoil SS 0W30 on the next one.

may eventually switch to that as the motor ages… I use Amsoil on my Harley 114 as well and it runs noticeably cooler than the regular Harley Syn3, so I switched from Pennzoil Ultra Plat to Amsoil in all my cars now too

I’ve been seeing a ton of ads lately for “Prolube”

father son type brand that they swear works better than all the additives out there. Any experience?
I

 

[bmpcamry09]

may eventually switch to that as the motor ages… I use Amsoil on my Harley 114 as well and it runs noticeably cooler than the regular Harley Syn3, so I switched from Pennzoil Ultra Plat to Amsoil in all my cars now too

I’ve been seeing a ton of ads lately for “Prolube”

father son type brand that they swear works better than all the additives out there. Any experience?
I

Never heard of them. I like Lake the Oil Geek guys videos on YouTube. He stays up to date on what’s the best out there.

 

[mwilk012]

Bank 1 …13,000 miles. Switched to Amsoil Signature 5w-30 no issues since

This is about as statistically relevant as someone who says “I got sunburned every summer, I never got cancer.”

The prevalence of failure of the intake cam on bank 1 is well documented and appears to be at least 15-20x more common than bank 2. This cannot be a coincidence at scale.

 

[mwilk012]

But this is an absolute...

 

[roaniecowpony]

I'm not buying into a defective material (metallurgy) or condition (heat treat, hardness, finish, etc.). First, the metallurgy for camshafts, lifters, rockers, etc., are pretty basic and a well worn path (no pun intended). Then the fact that it really hasn't changed over the years, and even carried over from the 1st gen Pentastar, indicates that there is a continuity between the 1st gen Pstar and the PUG on this problem. If it were materials or condition, it could have been easily tracked down and fixed. My suspicions point to the hydraulic lifter function in those few locations that we see failing over and over. There's a trend on which position (cylinder #) cam lobes/rockers fail more than others. I suspect it's about oil pressure, or more specifically, delayed or reduced oil pressure at these locations feeding the lifter, causing the rocker to collapse and beat/hammer on the cam lobe, and it's repetitive.

 

[mwilk012]

I'm not buying into a defective material (metallurgy) or condition (heat treat, hardness, finish, etc.). First, the metallurgy for camshafts, lifters, rockers, etc., are pretty basic and a well worn path (no pun intended). Then the fact that it really hasn't changed over the years, and even carried over from the 1st gen Pentastar, indicates that there is a continuity between the 1st gen Pstar and the PUG on this problem. If it were materials or condition, it could have been easily tracked down and fixed. My suspicions point to the hydraulic lifter function in those few locations that we see failing over and over. There's a trend on which position (cylinder #) cam lobes/rockers fail more than others. I suspect it's about oil pressure, or more specifically, delayed or reduced oil pressure at these locations feeding the lifter, causing the rocker to collapse and beat/hammer on the cam lobe, and it's repetitive.

There is no oil pressure at the sliding cam lobe. I can attest that 100% without question there are problems with many suppliers metal composition with regard to engine internals. Especially during Covid, one of our engine suppliers was having problems with camshafts and bearings not having the proper finish or alloy composition across multiple engine lines as tested in a lab. It is a problem when the source is not properly controlled.

 

[roaniecowpony]

There is no oil pressure at the sliding cam lobe. I can attest that 100% without question there are problems with many suppliers metal composition with regard to engine internals. Especially during Covid, one of our engine suppliers was having problems with camshafts and bearings not having the proper finish or alloy composition across multiple engine lines as tested in a lab. It is a problem when the source is not properly controlled.

I think you must have read something else besides my post.

 

[azjl#3]

If I keep this long enough, I'm going 5w40. I'm in Az, the 5 lets it work fine cold, the 40 lets it pur at 120 degrees road temp.

I'm not buying into a defective material (metallurgy) or condition (heat treat, hardness, finish, etc.). First, the metallurgy for camshafts, lifters, rockers, etc., are pretty basic and a well worn path (no pun intended). Then the fact that it really hasn't changed over the years, and even carried over from the 1st gen Pentastar, indicates that there is a continuity between the 1st gen Pstar and the PUG on this problem. If it were materials or condition, it could have been easily tracked down and fixed. My suspicions point to the hydraulic lifter function in those few locations that we see failing over and over. There's a trend on which position (cylinder #) cam lobes/rockers fail more than others. I suspect it's about oil pressure, or more specifically, delayed or reduced oil pressure at these locations feeding the lifter, causing the rocker to collapse and beat/hammer on the cam lobe, and it's repetitive.

not seeing an oil pressure issue, if it was, you would definitely hear it all the time, everyone would hear it all the time. But, we don't, until it turns into a tick for some people, not all.

I also don't buy some engineer stating to rev it to properly lube the top end. Thats a band aid to a problem not identified and a comment made with no support. 30 psi is plenty to lube everything in that motor, if it wasn't, they would have designed it for 70psi.

The problem is the components wearing. I don't think it's the oil viscosity, although even I am trying 5w30, because if it was mopar would tell us to use 5w30-40. And because not all engines are tapping, it's a segment of some, an obvious imo manufacturing problem, and since it's metal on metal, its a metallurgy 101 failure, not hardened enough, wrong metal, etc.

But, no one will know unless mopar tells us whats behind their curtain, because, they know what it is.

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