3.6 pentastar 2020 major problems - Is the newer engine better in 2025 etc.

[Hoss63]

Yeah, you'd better use that trailer to carry a spare engine.

She's gonna blow, cap'n!

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[Hoss63]

Guess I've past my time as had right bank replaced under warranty at around 20,000 miles and last week with 51,000 miles right bank went bad again. Engine light on and sounds like a diesel. wish they would figure out issues this will get costly.

 

[Stan H]

I am almost ready to turn 130k will tomorrow or next day and I was running mine 3k-4k alot going to and coming home. I have exclusively used Amsoil signature series 0W-20 and Wix filters. 1 or 2 times I used an Amsoil filter . The most unique thing I do is when the oil minder gets to 50% I change filter . Then when it gets to 10-15% oil and filter . Then reset the oil minder. I see 220-230 alot (antifreeze) 197 transmission 203-217 oil alot . It isnt unusual for me to do 4.5-5k a couple times a week. I haven't put it to 6k since back in the fall . That was only because I go to pass this guy He speeds up and so I got down on ot harder then seen a car coming so I just committed.

 

[Q Tip]

Very interesting thread and great to read the comments of all the long time techs. One thing I didn't see in reading was any mention of anyone doing hardness tests on failed cams. I have access to a calibrated Rockwell tester at work if anyone wants to send me a spent cam I'll post the Rc numbers here.

 

[ShadowsPapa]

Very interesting thread and great to read the comments of all the long time techs. One thing I didn't see in reading was any mention of anyone doing hardness tests on failed cams. I have access to a calibrated Rockwell tester at work if anyone wants to send me a spent cam I'll post the Rc numbers here.

I'll assume you would check the undamaged lobes, and/or the undamaged portions of the damaged lobes, since the hardness of a cam often doesn't go very deep......... thus, once they start, they go fast.

 

[Stan H]

I'll assume you would check the undamaged lobes, and/or the undamaged portions of the damaged lobes, since the hardness of a cam often doesn't go very deep......... thus, once they start, they go fast.

That makes since because the cam itself as a whole cant be too hard or it would snap under extreme load

 

[Chasm]

That makes since because the cam itself as a whole cant be too hard or it would snap under extreme load

For general OEM cams, they are just going to be surface hardened. That will be pretty hard, potentially 60+R/c. Internally they will still be "soft" at 25-30R/c. Of course when done wrong, surface hardening can lead to the surface flaking away under load...

 

[Stan H]

For general OEM cams, they are just going to be surface hardened. That will be pretty hard, potentially 60+R/c. Internally they will still be "soft" at 25-30R/c. Of course when done wrong, surface hardening can lead to the surface flaking away under load...

Yes I am sure they flex to a minute degree , and flaking yes I have seen thst during knife making during repeated heat treatments.
I would love to see the heat treatment process being done on these cams .
For instance modern knife steel uses heat and cryogenic treatments to increase metal density and hardness without delamination or flaking.
The hardness of a bearing race is ultra hard yet can take an ultra am9unt of abuse with lubrication.
I know they are hard enough you can strike one with a hammer and it will shatter.
I also agree with previous poster LOVE to know the hardness on those lobes especially in the spots shadows papa described the undamaged area and an undamaged lobe in the highspot.

 

[Chasm]

For instance modern knife steel uses heat and cryogenic treatments to increase metal density and hardness without delamination or flaking.

I've seen racing cams that used cryo.
Some OEM do nitriding to increase the surface hardness even further.

Depending on the steel, with tempering you can still be REALLY hard and not brittle. I doubt Jeep is using anything exotic though.

 

[Stan H]

I've seen racing cams that used cryo.
Some OEM do nitriding to increase the surface hardness even further.

Depending on the steel, with tempering you can still be REALLY hard and not brittle. I doubt Jeep is using anything exotic though.

They should be cause all their problem would disappear
I said for a while that I believe it is inconsistencies in the manufacturing process that has lead to problems in ine motor and then problems another motor there. I have 130k on mine and it runs like the day I rolled it off the lot,

 

[ShadowsPapa]

For general OEM cams, they are just going to be surface hardened. That will be pretty hard, potentially 60+R/c. Internally they will still be "soft" at 25-30R/c. ................................

Yes, this is exactly why I asked- what's going to be tested, where..............

 

[ShadowsPapa]

I've seen racing cams that used cryo.
Some OEM do nitriding to increase the surface hardness even further.

Depending on the steel, with tempering you can still be REALLY hard and not brittle. I doubt Jeep is using anything exotic though.

Nailed it there.

 

[Charles 236]

Intake cam from a Classic Pentastar in a Jeep Grand Cherokee. I have long considered inconsistent quality control to be a factor in the rare 3.6 Pentastar failures, both the Classic Pentastar and the PUG.

 

[Stan H]

Intake cam from a Classic Pentastar in a Jeep Grand Cherokee. I have long considered inconsistent quality control to be a factor in the rare 3.6 Pentastar failures, both the Classic Pentastar and the PUG.

Holy Crapola , I would never have ever imagined that one would snap they dont accelerate that fast

 

[ShadowsPapa]

Holy Crapola , I would never have ever imagined that one would snap they dont accelerate that fast

Crankshafts snap due to twisting under load, acceleration forces and such, cams have impact loads on them.

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