392 6.4L Hemi Recommend Engine Break-in Procedures?

[byhumba]

I Found this on page 143 of the 2021 manual. - Copied and pasted here.

"ENGINE BREAK-IN RECOMMENDATIONS — GASOLINE ENGINE (IF EQUIPPED) A long break-in period is not required for the engine and drivetrain (transmission and axle) in your vehicle. Drive moderately during the first 300 miles (500 km). After the initial 60 miles (100 km), speeds up to 50 or 55 mph (80 or 90 km/h) are desirable. While cruising, brief full-throttle acceleration within the limits of local traffic laws contributes to a good break-in. Wide-open throttle acceleration in low gear can be detrimental and should be avoided. The engine oil installed in the engine at the factory is a high-quality energy conserving type lubricant. Oil changes should be consistent with anticipated climate conditions under which vehicle operations will occur."

Just my mumbo jumbo below this line.
My SRT wouldn't permit a launch prior to 500 miles. Aside from that, I just drive them. I didn't do a lot of full throttle. But it was hard not to... With my SRT, I just drove "normally" for 500 miles. Outside of that, just no quick stops, towing, etc. I also change out that initial oil fill at 2500 miles. And again at 5000 miles. I did do the first launch at around 600 miles.
At 50k on the odometer now and still, not a single issue. I also change the oil every 5k with Mobil 1, 0-40 synthetic, regardless of the % of oil life.
The BMW, I drove easy for the first 500. Even though they say it's not necessary. I was told by a rep for BMW at the recent autocross event, it was more about litigious concerns here in the US. The thought? If there is a failure, it will be at a lower speed (RPM and MPH). Not sure how much of this is true though. However, it does make sense.

I bought a few Volvos which didn't require any break in. Why? They hook up every motors to an engine stand and run it to within 1k to the redline. Their belief is, if it's going to blow, best to have it do so at the factory. Watching this done at the plant in Gothenberg was pretty cool to watch.

That's not what I have in my 2021 manual page 143. Our 392s came with two booklets, 2021 Wrangler Owner's Manual and 2021 Wrangler Rubicon 392 Performance Features Guide. The guide has the specific 392 engine break-in recommendations on page 6.

 

[Jeepstin392]

That's not what I have in my 2021 manual page 143. Our 392s came with two booklets, 2021 Wrangler Owner's Manual and 2021 Wrangler Rubicon 392 Performance Features Guide. The guide has the specific 392 engine break-in recommendations on page 6.

Wow! Can you share?

 

[byhumba]

Wow! Can you share?

 

[byhumba]

Wow! Can you share?

Which manual shows what you quoted on page 143?

 

[Jeepstin392]

Which manual shows what you quoted on page 143?

The general wrangler manual
Not a supplement

 

[Jeepstin392]

View attachment 1309View attachment 1310

I believe that is similar to the SRT I have.

 

[ThunderBear]

Hey - I posted this in another forum and also wanted to post it here...
Can anyone who already has their 392 check in the Owner's Manual for the recommended Engine Break-in Procedures and post them here?
I've already seen a couple of "yayhoo-toob" videos of new owners and even salesmen at the dealership running these things (questionably) hard... and then there are a number of new owners whom have reported their 392s had at least 20 or more miles already on them when they arrived at the dealership.

Are we not all aware of the "factory recommended break-in period" for the 6.4L Hemi?
I'm sure it is published in the Owner's Manual, but since I don't have mine yet, I've provided what might be the appropriate snippets from my son's 2020 Dodge Charger 392 6.4L Hemi Widebody... I'm sure there are going to be some similarities:

ENGINE BREAK-IN RECOMMENDATIONS
The following tips will be helpful in obtaining optimum performance and maximum durability for your new SRT vehicle.
Despite modern technology and World Class manufacturing methods, the moving parts of the vehicle must still wear in with each other. This wearing in occurs mainly during the first 500 miles (805 km) and continues through the first oil change interval.
It is recommended for the operator to observe the following driving behaviors during the new vehicle break-in period:
0 to 100 miles (0 to 161 km):
• Do not allow the engine to operate at idle for an extended period of time.
• Depress the accelerator pedal slowly and not more than halfway to avoid rapid acceleration.
• Avoid aggressive braking.
• Drive with the engine speed less than 3,500 RPM.
• Maintain vehicle speed below 55 mph (88 km/h) and observe local speed limits.
100 to 300 miles (161 to 483 km):
• Depress the accelerator pedal slowly and not more than halfway to avoid rapid acceleration in lower gears (1st to 3rd gears).
• Avoid aggressive braking.
• Drive with the engine speed less than 5,000 RPM.
• Maintain vehicle speed below 70 mph (112 km/h) and observe local speed limits.
300 to 500 miles (483 to 805 km):
• Exercise the full engine rpm range, shifting manually at higher rpms when possible.
• Do not perform sustained operation with the accelerator pedal at wide open throttle.
• Maintain vehicle speed below 85 mph (136 km/h) and observe local speed limits.
For the first 1500 miles (2414 km):
• Do not participate in track events, sport driving schools, or similar activities during the first 1500 miles (2414 km).

How do we know procedures(?) were followed on such a vehicle that arrives at the dealership with 20+ miles on it?

So, yes, I'm asking someone to look in their glovebox, find the new shrink-wrapped Owner's Manual, unwrap it and actually look for the procedures.

So uhm... yeah... My dealership said drive it like you normally drive. I said, drive it like I stole it? They said yeah, if that's how you drive. They said If it's gonna break, it's an infant mortality and we'll warranty it. Not sure if we even hit a 100 miles on the odometer before I rapped it out against the speed governor (I saw 100Mph) while passing a couple semi's.

Not once has she squealed, she drive's like a champ every day.

 

[cgrosen324]

I’ve never owned a vehicle with a HEMI; the closest I’ve gotten was a 2014 Raptor with the 6.2L V8 and I don’t remember anything about a break in period. I get that this info is in the manual, and admittedly I’m spit-balling here, but this all sounds like something my pop told me you’re supposed to do with a new car…in the 1970’s. I was under the impression we were way past this with more modern engines. Don’t get me wrong, I’m not planning on being too hard on it when I first get my 392 (if I ever get it!), but is this engine break in really necessary? If so why?

 

[Viking Jeeper]

Engine break in will be discussed, debated, ridiculed, and followed closely as long as there are automobile enthusiasts. Pick any one of dozens of subjects and you will find people on both sides.

My dealer is 150 miles from home, I plan to pretty much go by break in recommendations. I will drive the 150 home without going on the interstate then the next day will cruise A1A down to Daytona and back on US1. By then I will be at 300 and look out.

 

[JeepnJam]

I’ve never owned a vehicle with a HEMI; the closest I’ve gotten was a 2014 Raptor with the 6.2L V8 and I don’t remember anything about a break in period. I get that this info is in the manual, and admittedly I’m spit-balling here, but this all sounds like something my pop told me you’re supposed to do with a new car…in the 1970’s. I was under the impression we were way past this with more modern engines. Don’t get me wrong, I’m not planning on being too hard on it when I first get my 392 (if I ever get it!), but is this engine break in really necessary? If so why?

I picked mine up and with 50 miles on it, blew the doors off a c6 Corvette at WOT. I now have ~4,000 miles and no troubles so far. First oil change is coming up.

 

[Idaho392]

I agree... drive it like you stole it, from day 1. When you take a vehicle on a test drive, do you follow the "break-in" procedures?? I sure don't. I push it to redline in at least the first 3-4 gears.

There is also the theory that the ECU/PCM learns your driving habits over time.

 

[Big500]

Here is the information from the 392 supplemental manual.

 

[byhumba]

I see the break-in period as eating vegetables at a young age. Eating them decreases the likelihood of health problems later in life. It doesn't mean eating vegetables when young or following brek-in procedure will prevent all problems later, but they will decrease the likelihood of experiencing some problems...or at least delay them.

 

[HearHear]

If your engine has 20 or 40 miles on it already when you pick it up at the dealer, how do you know the young tech who prepped it didn’t floor it a few times on the way to get gas? That worries me. I think I‘m calling the service manager to have a talk before mine arrives.

 

[Ward]

Hey - I posted this in another forum and also wanted to post it here...
Can anyone who already has their 392 check in the Owner's Manual for the recommended Engine Break-in Procedures and post them here?
I've already seen a couple of "yayhoo-toob" videos of new owners and even salesmen at the dealership running these things (questionably) hard... and then there are a number of new owners whom have reported their 392s had at least 20 or more miles already on them when they arrived at the dealership.

Are we not all aware of the "factory recommended break-in period" for the 6.4L Hemi?
I'm sure it is published in the Owner's Manual, but since I don't have mine yet, I've provided what might be the appropriate snippets from my son's 2020 Dodge Charger 392 6.4L Hemi Widebody... I'm sure there are going to be some similarities:

ENGINE BREAK-IN RECOMMENDATIONS
The following tips will be helpful in obtaining optimum performance and maximum durability for your new SRT vehicle.
Despite modern technology and World Class manufacturing methods, the moving parts of the vehicle must still wear in with each other. This wearing in occurs mainly during the first 500 miles (805 km) and continues through the first oil change interval.
It is recommended for the operator to observe the following driving behaviors during the new vehicle break-in period:
0 to 100 miles (0 to 161 km):
• Do not allow the engine to operate at idle for an extended period of time.
• Depress the accelerator pedal slowly and not more than halfway to avoid rapid acceleration.
• Avoid aggressive braking.
• Drive with the engine speed less than 3,500 RPM.
• Maintain vehicle speed below 55 mph (88 km/h) and observe local speed limits.
100 to 300 miles (161 to 483 km):
• Depress the accelerator pedal slowly and not more than halfway to avoid rapid acceleration in lower gears (1st to 3rd gears).
• Avoid aggressive braking.
• Drive with the engine speed less than 5,000 RPM.
• Maintain vehicle speed below 70 mph (112 km/h) and observe local speed limits.
300 to 500 miles (483 to 805 km):
• Exercise the full engine rpm range, shifting manually at higher rpms when possible.
• Do not perform sustained operation with the accelerator pedal at wide open throttle.
• Maintain vehicle speed below 85 mph (136 km/h) and observe local speed limits.
For the first 1500 miles (2414 km):
• Do not participate in track events, sport driving schools, or similar activities during the first 1500 miles (2414 km).

How do we know procedures(?) were followed on such a vehicle that arrives at the dealership with 20+ miles on it?

So, yes, I'm asking someone to look in their glovebox, find the new shrink-wrapped Owner's Manual, unwrap it and actually look for the procedures.

I am fully aware of the shenanigans at dealers with high performance vehicles. I was there the day it arrived and did not leave until I was in it. I arrived with 7 miles on it and I got it with 9 miles on it. Did not take any chances.

 

[dblplay1212]

Glad I came across this thread. Never really thought about breaking it in. I just got the call today that mine was delivered to the dealer today. They have to ship it to me but I should have it next week. Thought about taking it on a Thanksgiving trip that will be about 800 miles, all interstate. Would doing 70 over that 800 miles be a huge deal? I know it says 55 but I wouldn't be flooring it or anything.

 

[JEEPGEEK]

Glad I came across this thread. Never really thought about breaking it in. I just got the call today that mine was delivered to the dealer today. They have to ship it to me but I should have it next week. Thought about taking it on a Thanksgiving trip that will be about 800 miles, all interstate. Would doing 70 over that 800 miles be a huge deal? I know it says 55 but I wouldn't be flooring it or anything.

Sounds like your drive home is the perfect opportunity to perform a proper break in.

It's only 55MPH/under 3500RPM for the first 100 miles.

100-300 miles = 70MPH/5500RPM limit

300-500 miles = 85MPH and full range of RPM, but no extended FUN...I mean high RPM.

Congrats and enjoy the ride!

 

[dblplay1212]

Sounds like your drive home is the perfect opportunity to perform a proper break in.

It's only 55MPH/under 3500RPM for the first 100 miles.

100-300 miles = 70MPH/5500RPM limit

300-500 miles = 85MPH and full range of RPM, but no extended FUN...I mean high RPM.

Congrats and enjoy the ride!

So baby it for the first 100 miles and then drive 70 for the rest of the trip? I can make that work. Just take some backroads leaving town. Appreciate the break down. Going to cost a fortune to take it on the trip but my nephews will love and it breaks in the engine so win/win.

 

[70sKid]

I’ve never owned a vehicle with a HEMI; the closest I’ve gotten was a 2014 Raptor with the 6.2L V8 and I don’t remember anything about a break in period. I get that this info is in the manual, and admittedly I’m spit-balling here, but this all sounds like something my pop told me you’re supposed to do with a new car…in the 1970’s. I was under the impression we were way past this with more modern engines. Don’t get me wrong, I’m not planning on being too hard on it when I first get my 392 (if I ever get it!), but is this engine break in really necessary? If so why?

I've got just over 100 miles on mine and I'm giving it a "hard" break-in. From prior experience and a little research on the subject, the critical piston ring-to-cylinder wall seal must be created during break-in. No amount of modern tech will do this task. What modern tech will do, however, is hone the cylinder walls in a specific cross-hatch pattern with just the right amount of roughness to sand down the rings. These rings must be forced against the cylinder walls with sufficient pressure in order for this seal to form. If the rings are not forced with enough pressure in enough time, the cross-hatch will be polished smooth before the rings fully set, and the motor will never achieve that critical seal. What's worse, it will likely consume oil and be under powered.
So, how does one create this seal safely? It's all about accelerating for brief periods followed by deceleration/engine breaking. This last step is very important as it allows the rings to snap back from the cylinder walls so the oil can get in and around them to cool and flush out all the metal debris created during the acceleration phase. All that oil then goes out the exhaust. The biggest problem with this break-in approach is cylinder temperatures. Since there are no temp sensors on the heads, one must be conservative about how often this acceleration/deceleration is performed.
With the 392 Wrangler, you must keep the transmission in manual mode in order to achieve the engine deceleration/breaking. As the manual states, I tend to avoid snappy, to-the-floor pedal stomping early on and give gradual pedal input so the motor can slowly wind out. Then I'll gently lift the throttle and allow it to engine break/decelerate. I also honor the RPM limits somewhat and try not to abuse those guidelines. If I'm a little aggressive on a given "pull" then I'll allow more time between the next one so everything can cool down. Lastly, the rings are not the only components breaking in, so it's wise to accelerate smoothly to give the transmission/driveline a chance to cool down as well.

 

[cgrosen324]

I've got just over 100 miles on mine and I'm giving it a "hard" break-in. From prior experience and a little research on the subject, the critical piston ring-to-cylinder wall seal must be created during break-in. No amount of modern tech will do this task. What modern tech will do, however, is hone the cylinder walls in a specific cross-hatch pattern with just the right amount of roughness to sand down the rings. These rings must be forced against the cylinder walls with sufficient pressure in order for this seal to form. If the rings are not forced with enough pressure in enough time, the cross-hatch will be polished smooth before the rings fully set, and the motor will never achieve that critical seal. What's worse, it will likely consume oil and be under powered.
So, how does one create this seal safely? It's all about accelerating for brief periods followed by deceleration/engine breaking. This last step is very important as it allows the rings to snap back from the cylinder walls so the oil can get in and around them to cool and flush out all the metal debris created during the acceleration phase. All that oil then goes out the exhaust. The biggest problem with this break-in approach is cylinder temperatures. Since there are no temp sensors on the heads, one must be conservative about how often this acceleration/deceleration is performed.
With the 392 Wrangler, you must keep the transmission in manual mode in order to achieve the engine deceleration/breaking. As the manual states, I tend to avoid snappy, to-the-floor pedal stomping early on and give gradual pedal input so the motor can slowly wind out. Then I'll gently lift the throttle and allow it to engine break/decelerate. I also honor the RPM limits somewhat and try not to abuse those guidelines. If I'm a little aggressive on a given "pull" then I'll allow more time between the next one so everything can cool down. Lastly, the rings are not the only components breaking in, so it's wise to accelerate smoothly to give the transmission/driveline a chance to cool down as well.

Thank you for the detailed write-up. How does your break-in process differ from what’s in the manual? By no means am I being sarcastic; I really want to get this right before mine is delivered (est end of Jan). Thanks again!