Jeep Garage  - Jeep Forum

Jeep Garage - Jeep Forum (http://www.jeepgarage.org/forums.php)
-   Engine Performance/Intakes/Exhausts (http://www.jeepgarage.org/f108/)
-   -   What's The Best Way To Break-In the Hemi ?? (http://www.jeepgarage.org/f108/whats-the-best-way-to-break-in-the-hemi-20820.html)

K9jackie 03-27-2011 12:00 AM

What's The Best Way To Break-In the Hemi ??
 
What's The Best Way To Break-In the Hemi ?? I have only driven 40 easy miles... just 2 miles on the freeway but I plan to take it out for a spin tomorrow. Should I run it hard or easy? For how many miles?

The dealer didn't put any gas in my jeep, so I took it to costco and accidentally filled it with 87 instead of plus or premium. Will that effect the break in?

Sorry if this is a repost. I'm sure someone must have asked this but the search is not coming up with anything.


Thanks :D
Jackie

Dan JGC 03-27-2011 12:18 AM

Re: What's The Best Way To Break-In the Hemi ??
 
Best to use 89 instead of 87....for best performance. I was told to NOT use above 89 since it burns hotter (that's what the dealer said).

I have about 240 miles on mine. I did put Interstate miles on mine at first and I picked it up at 5 miles on the odometer. I suppose I could have avoided the Interstate and taken other roads. Filled it up with mid-grade 89 which is what I will use.

Someone had posted...or maybe it was Jeep...about the first 50 miles to be gentle. I was told by the dealer not to pull the full towing of 7000+ lb for something like the first 2K miles...something about the breaks breaking in....dunno, I don't tow so didn't pay attention to remember.

Dan JGC 03-27-2011 12:20 AM

Re: What's The Best Way To Break-In the Hemi ??
 
BTW....don't ya just love your Black Summit??? Mine is fantastic and lovin' it!

JP49 03-27-2011 12:42 AM

Re: What's The Best Way To Break-In the Hemi ??
 
The dealer maintenance sup. told me to do the first oil change at 2500 miles, because they use a special oil mix for breaking in the engine. He also said synthetic oil is ok but change every 10,000 miles. That is his comments to me. I had no idea. I forgot to ask in my old age about how often the filter should be changed if using synthetic oil... Any one else know something different?

K9jackie 03-27-2011 12:54 AM

Re: What's The Best Way To Break-In the Hemi ??
 
Quote:

Originally Posted by Dan JGC (Post 383717)
BTW....don't ya just love your Black Summit??? Mine is fantastic and lovin' it!


Um, yeah :D. I really love it... It is the coolest car I have owned so far! :D It is much better than the BMW X5 I had. Love that the summit has all the gadgets too... It was fun learning how they worked today. The interior is heaven...can't really say enough about it. My friends and neighbors were drooling... They all want one too. Go jeep & USA :)

mjw930 03-27-2011 08:32 AM

Re: What's The Best Way To Break-In the Hemi ??
 
The key to breaking in the motor is to keep it from developing hot spots, that's best accomplished by varying the RPMs and driving conditions hence the typical comments to not maintain any one speed for too long. Being "good" to the motor for the first 50 miles is always a good idea, both for the motor and the rest of the drivetrain. From there I would basically drive it as you normally would with the exception of this tidbit that comes from the Owners Manual:

Quote:

ENGINE BREAK-IN RECOMMENDATIONS
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. For
the recommended viscosity and quality grades refer to
“Maintenance Procedures” in “Maintaining Your Vehicle”.
NON-DETERGENT OR STRAIGHT MINERAL
OILS MUST NEVER BE USED.

A new engine may consume some oil during its first few
thousand miles (kilometers) of operation. This should be
considered a normal part of the break-in and not interpreted
as an indication of difficulty.
That section seems to confirm the long held belief by many who have built performance engines that proper seating of the rings is best achieved by WOT Acceleration and Deceleration to apply equal upward and downward pressure on the rings. It's interesting (and welcome) to see it in print from a major engine manufacturer.

Since I plan on pulling a 5000 lb load before I reach the 2000 mile mark (probably around 1000 miles on the clock) I changed to 100% synthetic oil with a new filter @ 650 miles. Aside from that I've been driving it as normal and it's been running in quite nicely.

Dan JGC 03-27-2011 09:32 AM

Re: What's The Best Way To Break-In the Hemi ??
 
^^^ Thanks for posting the quote. I did drive on the Interstate after 10....didn't gun it though....so was reasonably gentle...but the thing did want to cruise easily over 60 to 70.

One thing it does not say is whether WOT should be done within the first 300 miles...it is ambiguous as to when this should be done.

Jpjr 03-27-2011 09:50 AM

Re: What's The Best Way To Break-In the Hemi ??
 
Quote:

Originally Posted by Dan JGC (Post 383715)
Best to use 89 instead of 87....for best performance. I was told to NOT use above 89 since it burns hotter (that's what the dealer said).

I have about 240 miles on mine. I did put Interstate miles on mine at first and I picked it up at 5 miles on the odometer. I suppose I could have avoided the Interstate and taken other roads. Filled it up with mid-grade 89 which is what I will use.

Someone had posted...or maybe it was Jeep...about the first 50 miles to be gentle. I was told by the dealer not to pull the full towing of 7000+ lb for something like the first 2K miles...something about the breaks breaking in....dunno, I don't tow so didn't pay attention to remember.


The HEMI motor was tuned this time around to run on regular (i.e., 87 octane gas), sheerly for cost savings. Ideally when you buy a HEMI you buy it for power, and your dealer is right the higher octane gas burns "hotter". Without getting into details he means that the ignition temp of 91 octane gas is higher than 87 octane gas, allowing the engine's computer to add timing and boost the power stroke of the motor. Stated differently, since the ignition temp is higher the chance of detonation (i.e., gas exploding prematurely and damaging the motor rather than pushing the piston) is lower so the motor can safely make more power.

I continue to fill my HEMI with premium gas for power as I did with my '08.. but unlike a few years ago you can fill most V8 engines with regular gas (vs premium only) today as well. My CTS-V still requires premium however as do almost all higher compression motors.

Dan JGC 03-27-2011 10:15 AM

Re: What's The Best Way To Break-In the Hemi ??
 
Doesn't the manual say use 89, but 87 is "acceptable". It says nothing about 91.

GTOGreg 03-27-2011 11:24 AM

Re: What's The Best Way To Break-In the Hemi ??
 
vary RPM as was already said and you're good. Oil change at 2500 is a good idea. Otherwise, drive it how you normally would.

slampert 03-27-2011 11:25 AM

Re: What's The Best Way To Break-In the Hemi ??
 
Dan--you've got to take a nice long cruise down to Key West and get that truck broken in !

While there appears to be a solid consensus concerning the use of 89 fuel, I don't understand why there is so much debate on recommended motor oil for the 5.7.

When I suggested changing over to synthetic my dealer / service manager replied with an emphatic "Don't !!"

Sammzway 03-27-2011 12:21 PM

Re: What's The Best Way To Break-In the Hemi ??
 
Hey guys, i've been reading back and forth around this thread about the entire break in process.

I just picked up a 3.6 Laredo X (I take delivery next week) and this is my 1st brand new vehicle. Any different direction to break in the 3.6 compared to the HEMI? I heard you drive normal without WOT for the first 500 miles. After that you can drive it however you want. Also, should I change oil after 2500 too or after 5000?

Sorry for the thread jacking. :)


All times are GMT -5. The time now is 03:25 AM.

Powered by vBulletin® Version 3.8.8 Beta 4
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
Copyright 2012 - JeepGarage.Org
The Jeep Grand Cherokee Owners Community