626,000 mile Pentastar teardown

Originally Posted by OIL_UDDER
Nice! As an former Pentastar design engineer I am slightly bias but the engine is really high quality. Few points from the development using tens of millions of dollars in analysis and testing regarding the oil and durability.....

The lighter oil was chosen mostly for fuel economy BUT engineering is the science of compromise. You help one thing but hurt another.

A thicker oil will reduce timing chain and tensioner wear because the center timing chain idler doesn't go fully hydrodynamic till about 1650rpm on 5w-20. So, a thicker oil will lower that number slightly and with general loads/speeds the engine spends a lot of time around 1500-1750 rpm with the 8 speed. So thicker oil is a win there. Additionally, the earlier engines had what was called the "McDonald's Arches" in the idler bearing which was intended in making a more uniform distribution but in actuality acted as a knife edge. This design was changed around 2014 to a smooth bearing. So overall timing chain issues will likely follow the 2011-2014 engine years more than 2014+.


Where you lose.... The head is very complicated with a Type II valve train. Meaning lots of things to pressurize and pump up at start up. A thicker oil didn't do so well here (on long sit times +cold start) and contributed to a overall increased engine wear especially in the head and cam bearings.

Last point. This engine needs occasional WOT runs if you want it to last. Granny cycling is bad for it. So bad for it we actually created a new granny cycle test during the cylinder #3 misfire issue. The highest wear is in the valve guides, because of tight valve stem seals (for emissions, reduce oil burn). They basically dry out. When you go WOT/high rpm/load you get some fresh oil in there and this keeps the wear down. Thicker oil might not help this condition but we also change the valves/guides/seals in 2014+. Not sure the impact.

Cheers!

Kevin


PS. Turn off stop start and do not run e85 if you are concerned about engine wear. Eats the engine alive.


Thanks for sharing.
cheers3.gif


Sounds like a 20 grade with a higher HT/HS (such as Red Line) would be a nice choice for this engine (non api approved of course). Or an API approved 30 grade, most of which have a HT/HS of 3.-3.2.
 
Quote
I like this thinking. Most engines do like to be wound up now and then. I am fortunate to live on top of a hill. After a trip to the store where the SkyActiv motor is cruising at less than 2000rpm for the most part I make it a habit of going up this half mile stretch of hill in sport mode.


It certainly does seem that way. Engines like to be ran and often hard. While not scientific, you do see a lot of anecdotal evidence that suggests engines like to be driven on the more aggressive side at times. You also see that a lot of high mileage engines are driven a lot. Babying an engine is not ideal.
 
I always wondered what time frame car manufacturers had. Was this 150-200K miles just for this engine, or for Chrysler-Jeep as a whole, or do you think this is widespread throughout the auto industry?

EDIT: You are referencing OEMs, so that implies that it is widespread, but I'd still appreciate your thoughts on that question.


Originally Posted by OIL_UDDER
i wish I had some more data for you 2015_PSD,

Unfortunately I left the company as the Gen II was kicking off. I do know the engineering team was VERY nervous on the 0w-20 stuff and it was 100% for fuel economy. My personal opinion knowing the bearing surface area would not have gone up because of the cost I would go up a notch in weight. Not a lot of downside for the margin. Also, we are designing for 150-200K max, not 200k+ so that is always something to think about when OEM's make recommendations.

I would like to note there was this bearing coating they started using called iROX which was very impressive at the microscopic and testing level. It had to go on the front and back bearings to pass Stop-Start because of wear and was very expensive. They likely added that to the rest of bearings to make them work but I don't know for sure, I will have to ask. Regardless, the bearing surface area did not likely increase so from a basic physics point of view your hydrodynamic response to "filling it with water" as we called it will not go in a safer direction at lower rpm.
 
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I started running 5 30 in it year round when RTG came out, also run archoil in oil and occasional gas additive as well, always use premium fuel with no ethanol.....glad that was mentioned added bonus to paying bit extra, between added fuel economy and hearing that better fuel helps makes it worth extra cost. Also noticed no extra strain on engine during cold starts, actually noticed this year seemed that less strain on motor in temps below -20. Would sometimes get that belt whine or just notice during a cold start that engine isn't happy about the temp. Smooth starts in general since using RTG.
 
Originally Posted by buster
Quote
I like this thinking. Most engines do like to be wound up now and then. I am fortunate to live on top of a hill. After a trip to the store where the SkyActiv motor is cruising at less than 2000rpm for the most part I make it a habit of going up this half mile stretch of hill in sport mode.


It certainly does seem that way. Engines like to be ran and often hard. While not scientific, you do see a lot of anecdotal evidence that suggests engines like to be driven on the more aggressive side at times. You also see that a lot of high mileage engines are driven a lot. Babying an engine is not ideal.




Yep. I think the occasional wind up is good.

Further thinking on the longevity of this motor, no mention was made of water pump replacement which is astounding to me. Not knowing the particulars of this engine, had the water pump been replaced earlier on, I wonder if the timing chain guides and tensioners would have been checked and maybe replaced thus extending the life of the engine even further?
 
Beefy internals but then it is a HD application so it should be robust. And yes these are ideal operating and maintenance conditions... long highway hauls and frequent synthetic oil changes, not really surprised it ran so long. I wonder if he ever came close to getting the maintenance light, I would guess not with the usage. Pretty sure my Tacoma 4-cylinder would run just as long under these conditions.
 
Originally Posted by OIL_UDDER
Nice! As an former Pentastar design engineer I am slightly bias but the engine is really high quality. Few points from the development using tens of millions of dollars in analysis and testing regarding the oil and durability.....

The lighter oil was chosen mostly for fuel economy BUT engineering is the science of compromise. You help one thing but hurt another.

A thicker oil will reduce timing chain and tensioner wear because the center timing chain idler doesn't go fully hydrodynamic till about 1650rpm on 5w-20. So, a thicker oil will lower that number slightly and with general loads/speeds the engine spends a lot of time around 1500-1750 rpm with the 8 speed. So thicker oil is a win there. Additionally, the earlier engines had what was called the "McDonald's Arches" in the idler bearing which was intended in making a more uniform distribution but in actuality acted as a knife edge. This design was changed around 2014 to a smooth bearing. So overall timing chain issues will likely follow the 2011-2014 engine years more than 2014+.


Where you lose.... The head is very complicated with a Type II valve train. Meaning lots of things to pressurize and pump up at start up. A thicker oil didn't do so well here (on long sit times +cold start) and contributed to a overall increased engine wear especially in the head and cam bearings.

Last point. This engine needs occasional WOT runs if you want it to last. Granny cycling is bad for it. So bad for it we actually created a new granny cycle test during the cylinder #3 misfire issue. The highest wear is in the valve guides, because of tight valve stem seals (for emissions, reduce oil burn). They basically dry out. When you go WOT/high rpm/load you get some fresh oil in there and this keeps the wear down. Thicker oil might not help this condition but we also change the valves/guides/seals in 2014+. Not sure the impact.

Cheers!

Kevin


PS. Turn off stop start and do not run e85 if you are concerned about engine wear. Eats the engine alive.


Thank you for your part in giving us a great engine and for this insight. I´ve got the Pentastar Upgrade or PUG in my 2018 JL Wrangler and I absolutely love it. I have a manual transmission, so I run it through the rpm band frequently, because it is fun and the engine sounds really good with the Magnaflow axle-back exhaust I put on it, especially with the doors off and top down.

I run 0w20, mainly Mobil 1 AP (will go to EP when AP is no longer available.) I think you confirmed what I thought I´ve heard about the Pentastar, especially the new one, with thinner oil being better for the valve train. I believe I read that engineers were adamant about 0w20 with the new one. Not sure how much was changed, but it did get some updates or redesign of some components, for sure.

I chuckle when we see an engine with over 600,000 miles and someone from the thick oil crowd chimes in as if that isn´t enough.

I don´t put enough miles on mine to ever worry about seeing anything near that kind of mileage. So it gives me great peace of mind that this Jeep and engine could easily outlast me.

This has honestly, all things considered, been one of the most enjoyable engines I´ve owned. I have great confifdence in it. The many friends I´ve known with the Pentastar over the years are all unanimous in their praise of it. Not one has had a complaint or a major issue. All have run whatever weight oil was specified.
 
Originally Posted by paulri
I always wondered what time frame car manufacturers had. Was this 150-200K miles just for this engine, or for Chrysler-Jeep as a whole, or do you think this is widespread throughout the auto industry?

EDIT: You are referencing OEMs, so that implies that it is widespread, but I'd still appreciate your thoughts on that question.


Originally Posted by OIL_UDDER
i wish I had some more data for you 2015_PSD,

Unfortunately I left the company as the Gen II was kicking off. I do know the engineering team was VERY nervous on the 0w-20 stuff and it was 100% for fuel economy. My personal opinion knowing the bearing surface area would not have gone up because of the cost I would go up a notch in weight. Not a lot of downside for the margin. Also, we are designing for 150-200K max, not 200k+ so that is always something to think about when OEM's make recommendations.

I would like to note there was this bearing coating they started using called iROX which was very impressive at the microscopic and testing level. It had to go on the front and back bearings to pass Stop-Start because of wear and was very expensive. They likely added that to the rest of bearings to make them work but I don't know for sure, I will have to ask. Regardless, the bearing surface area did not likely increase so from a basic physics point of view your hydrodynamic response to "filling it with water" as we called it will not go in a safer direction at lower rpm.




So the question is a little muddy if discussing powertrain vs chassis. The chassis teams go off mileage, trans teams hours and mileage, and engine teams mostly hours (over simplifying here). This is because "designed mileage" is basically a translation from customer miles to powertrain hours. So each particular OEM formula might be slightly different based on their customer data. Generally speaking 150K miles falls somewhere in the 3,500-4,000 engine hour range. Which is the design target for minimal customer issues (less than 3 per 1000 customers) and where the "designed for 150K" comes from.

It get's more complicated because things like aged catalytic converter performance is a major driver and obviously things like competitive pricing and length of ownership etc. So to trivialize, its a pretty complex thing. My data is based on experience and talking over beers with other engineers and program managers from firms like FEV and AVL and OEM's. That stated the 3500-4000 engine hours, or roughly 150K is the design target for statistically insignificant customer issues/complaints for most OEMs. Or no major issues like a bearing failure.

It's about "200K" for domestic trucks. That is roughly 5,000 hours. An increase of 33% because of the harder duty cycle.


Interesting data if you have it. My miles vs. hours right now are 162,501 @ 3929 engine hours. So right in that range.

Best,


Kevin


PS I also ignore chassis miles for oil changes and go entirely off engine hours. Every 200 hours.
 
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Originally Posted by OIL_UDDER
Originally Posted by paulri
I always wondered what time frame car manufacturers had. Was this 150-200K miles just for this engine, or for Chrysler-Jeep as a whole, or do you think this is widespread throughout the auto industry?

EDIT: You are referencing OEMs, so that implies that it is widespread, but I'd still appreciate your thoughts on that question.


Originally Posted by OIL_UDDER
i wish I had some more data for you 2015_PSD,

Unfortunately I left the company as the Gen II was kicking off. I do know the engineering team was VERY nervous on the 0w-20 stuff and it was 100% for fuel economy. My personal opinion knowing the bearing surface area would not have gone up because of the cost I would go up a notch in weight. Not a lot of downside for the margin. Also, we are designing for 150-200K max, not 200k+ so that is always something to think about when OEM's make recommendations.

I would like to note there was this bearing coating they started using called iROX which was very impressive at the microscopic and testing level. It had to go on the front and back bearings to pass Stop-Start because of wear and was very expensive. They likely added that to the rest of bearings to make them work but I don't know for sure, I will have to ask. Regardless, the bearing surface area did not likely increase so from a basic physics point of view your hydrodynamic response to "filling it with water" as we called it will not go in a safer direction at lower rpm.




So the question is a little muddy if discussing powertrain vs chassis. The chassis teams go off mileage, trans teams hours and mileage, and engine teams mostly hours (over simplifying here). This is because "designed mileage" is basically a translation from customer miles to powertrain hours. So each particular OEM formula might be slightly different based on their customer data. Generally speaking 150K miles falls somewhere in the 3,500-4,000 engine hour range. Which is the design target for minimal customer issues (less than 3 per 1000 customers) and where the "designed for 150K" comes from.

It get's more complicated because things like aged catalytic converter performance is a major driver and obviously things like competitive pricing and length of ownership etc. So to trivialize, its a pretty complex thing. My data is based on experience and talking over beers with other engineers and program managers from firms like FEV and AVL and OEM's. That stated the 3500-4000 engine hours, or roughly 150K is the design target for statistically insignificant customer issues/complaints for most OEMs. Or no major issues like a bearing failure.

It's about "200K" for domestic trucks. That is roughly 5,000 hours. An increase of 33% because of the harder duty cycle.


Interesting data if you have it. My miles vs. hours right now are 162,501 @ 3929 engine hours. So right in that range.

Best,


Kevin


PS I also ignore chassis miles for oil changes and go entirely off engine hours. Every 200 hours.


I´m guessing that means that engine hours is one of the data points, or is THE data point for the OLM in my 2018 JL Wrangler? I´ve changed oil according to it and it is usually 7k to 7800k at or near 0%. I´ve thought about changing oil at 5k, but I think with a high quality oil like Mobil 1 AP or EP, there is no downside, at all, to going with the OLM. I know GM´s OLM includes more than just hours in theirs, but also engine revolutions. Just curious what the OLM on the 3.6 uses for data.
 
One more thought....If designing an engine with ESS to go 150k to 200k miles, then I would think that not using it would stretch its life well beyond that. I think one of the reasons this particular 3.6 went over 600,000 miles was that it had fewer cold starts and starting/stopping cycles, running mostly long stints on the highway at full operating temp and at rpms that kept everything well lubricated. (I´m assuming it was mostly highway miles?)

Btw, my ESS has been disabled from early on. I use a Tazer JL programmer so I don´t have to remember to press the button every time I start up. Maybe the ESS is a gift in disguise. Since the durability target remains the same with the wear-inducing ESS taken into account, those of us not using it will get the benifit of a much longer lifespan for our engines? I can only hope!
eek.gif
 
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Its way more than just hours and RPM. FCA uses oil temp, air temp, load, rpm even fuel type (ethanol %) and more. It's super complicated but very impressive. I'm far from an expert but do know the OEM develops a perfect vs. reality algorithm based on those (and more) factors/inputs. They create a very controlled duty cycle that is basically the max oil life for that engine under ideal conditions. When you drive outside that cycle you are given a penalty per infraction against that perfect cycle (fractions of a percent). For example if you are super hard on it you get a "high blow by penalty" of value __%. Or maybe you ran the engine hard when it was cold AND cold outside (intake air temp data) because you were late for work in January. Resulting in a penalty of ___% kind of thing.

I don't know the specific details of those penalties but I do know (at the time) that is how the algorithm worked. Pretty interesting stuff.


As for the other comment yes, without a doubt turning off ESS will significantly reduce engine wear in the 3.6. I dealt directly with the data on that. I'll keep my comments to my limited experience but other engines are no different and will follow suit. Noted above was the need for iROX bearing coatings, these were entirely driven by ESS operating issues and VERY high engine wear. They provided a lower coefficient of friction (thus reduced wear) as the crankshaft made contact with the bearings (Fun fact: the front and rear bearings will have the most wear because of the accessory drive loading and trans loading). The problem is simple. A hydrodynamic bearing doesn't touch any other metal, it's just floating on oil. So when you stop the engine its like killing the throttle pulling a skier in a boat. The skier no longer is on top of the water and sinks, scraping the sandbar and wearing the down the ski. The engine is doing the same to itself every time ESS goes off. Crankshaft, cams, timing chains all go to zero velocity and grind against their metal neighbor.

E85 is another animal. it basically washes out the oil that is embedded in the cross hatching which is intended to actually hold oil. Also all other peaks and valleys of machined parts (nothing is actually smooth!) like the cams, timing chain etc. When you combined with ESS and E85 you are basically scraping metal on metal for a very high percentage of the engine life vs. a gasoline steady state cycle. It was so high the cylinder bores on our general durability runs with ESS were mirror smooth by the end. Very interesting stuff.

I wont run ESS or E85 for the record. lol
 
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Originally Posted by OIL_UDDER



As for the other comment yes, without a doubt turning off ESS will significantly reduce engine wear in the 3.6. I dealt directly with the data on that. I'll keep my comments to my limited experience but other engines are no different and will follow suit. Noted above was the need for iROX bearing coatings, these were entirely driven by ESS operating issues and VERY high engine wear. They provided a lower coefficient of friction (thus reduced wear) as the crankshaft made contact with the bearings (Fun fact: the front and rear bearings will have the most wear because of the accessory drive loading and trans loading). The problem is simple. A hydrodynamic bearing doesn't touch any other metal, it's just floating on oil. So when you stop the engine its like killing the throttle pulling a skier in a boat. The skier no longer is on top of the water and sinks, scraping the sandbar and wearing the down the ski. The engine is doing the same to itself every time ESS goes off. Crankshaft, cams, timing chains all go to zero velocity and grind against their metal neighbor.

E85 is another animal. it basically washes out the oil that is embedded in the cross hatching which is intended to actually hold oil. Also all other peaks and valleys of machined parts (nothing is actually smooth!) like the cams, timing chain etc. When you combined with ESS and E85 you are basically scraping metal on metal for a very high percentage of the engine life vs. a gasoline steady state cycle. It was so high the cylinder bores on our general durability runs with ESS were mirror smooth by the end. Very interesting stuff.

I wont run ESS or E85 for the record. lol


Interesting comment regarding ESS. I have 210k on my Prius which obviously has start stop. In general there have not been any engine wear issues related to ESS. Are Toyota engines built very differently?
 
Originally Posted by The Critic
Interesting comment regarding ESS. I have 210k on my Prius which obviously has start stop. In general there have not been any engine wear issues related to ESS. Are Toyota engines built very differently?

Perhaps check back in at 625K?
 
Originally Posted by OIL_UDDER
E85 is another animal. it basically washes out the oil that is embedded in the cross hatching which is intended to actually hold oil. Also all other peaks and valleys of machined parts (nothing is actually smooth!) like the cams, timing chain etc. When you combined with ESS and E85 you are basically scraping metal on metal for a very high percentage of the engine life vs. a gasoline steady state cycle. It was so high the cylinder bores on our general durability runs with ESS were mirror smooth by the end. Very interesting stuff.

I wont run ESS or E85 for the record. lol
Ford (for example) places E85 use into the severe category (at least on the 5.4L 3V engine), so there is at least one OEM who supports your thoughts.
 
[/quote]
Interesting comment regarding ESS. I have 210k on my Prius which obviously has start stop. In general there have not been any engine wear issues related to ESS. Are Toyota engines built very differently?[/quote]

I haven't had the chance to review a toyota engine with a CMM but the issue is fundamental to all journal bearings in any machine. This is why some machines bearings are pre-pressurized before you even start. So, you do likely have higher wear than if you did not use ESS but! it's important to note just because it's got "higher" wear doesn't mean it wouldn't last or the owner would never even know. It's just measurable in a A-B study.

Something else to note as with engines designed for ESS from the start is it allows the packaging of wider bearings from day one which scientifically reduces wear rate (at the price of friction, cost and packaging). But the wear rate can be reduced from the start and have less impact on longevity.

Also, engine fundamentals come into play. An I4 has 5 main bearings for 4 cylinders and each rod has its down journal bearing. Load to bearing area is pretty good. A V6, which is trying to add more cylinders to a smaller package has 4 mains with 2 rods per crank journal. Yes they're individually bigger but total bearing area is more difficult to package. So ESS on a V6 is likely higher than an I4.
 
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Good to hear as I just bumped up to 5w30 Mobil 1 for the summer. Always ran that in the 2012 3.6L Chrysler 200S when we had it without issue getting 31-34 hwy miles on trips depending if my lead foot significant other was driving or me.

I'll use up the 0w20 for the winters then stay with either 5w30 Mobil 1 or Pennzoil Platinum.
 
Originally Posted by OIL_UDDER
[/quote]
Interesting comment regarding ESS. I have 210k on my Prius which obviously has start stop. In general there have not been any engine wear issues related to ESS. Are Toyota engines built very differently?


I haven't had the chance to review a toyota engine with a CMM but the issue is fundamental to all journal bearings in any machine. This is why some machines bearings are pre-pressurized before you even start. So, you do likely have higher wear than if you did not use ESS but! it's important to note just because it's got "higher" wear doesn't mean it wouldn't last or the owner would never even know. It's just measurable in a A-B study.

Something else to note as with engines designed for ESS from the start is it allows the packaging of wider bearings from day one which scientifically reduces wear rate (at the price of friction, cost and packaging). But the wear rate can be reduced from the start and have less impact on longevity.

Also, engine fundamentals come into play. An I4 has 5 main bearings for 4 cylinders and each rod has its down journal bearing. Load to bearing area is pretty good. A V6, which is trying to add more cylinders to a smaller package has 4 mains with 2 rods per crank journal. Yes they're individually bigger but total bearing area is more difficult to package. So ESS on a V6 is likely higher than an I4.

[/quote]
Interesting points. Thank you!
 
Originally Posted by JHZR2

The correct thing to do is to actually measure timing chain wear, in terms of how many degrees the chain is out of timing, and if it is low enough, repair with an offset woodruff key, otherwise replace. Replacement is the most prudent.


I know it's an added expense, and I don't know the cost of the timing chain and tensioners on this engine, but when I had Ford 5.0s and other V8s, any time the front cover came off it got a new timing set. Sure, it was probably wasteful considering I almost always went with billet gears and double roller chains, but to me $60-100 for a new timing set was definitely worth the peace of mind of not worrying about stretch or breakage.

Now that I'm almost exclusively Subaru (and old EJs at that) I simply replace the timing belt, idlers, tensioner, and water pump every 100k and don't worry about it.

As far as the thicker oil goes, I'm not sure it would make a difference. Higher EP/AW levels would have more of an impact IMO.
 
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