What stresses/breaks in an engine more?

Discussion in 'Dodge Challenger Mechanical Problems and Questions' started by KVChallenger, Jul 14, 2017.

  1. KVChallenger

    KVChallenger New Member Site Supporter Level 1

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    Is it the RPMs or how far you press the throttle that puts more stress on the engine?

    For example, if Im in 2nd gear revving at 5k rpm but the throttle/gas pedal is only down say 5%

    OR

    Im in 5th gear at 3k rpm and floor it.

    Thanks in advance!

    (I would have posted this in the Engine sub forum but no privvys)
     
  2. SolApathy

    SolApathy New Member

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    Both of those actions would stress the engine. What exactly are you attempting to accomplish, or avoid? You can break in an engine with normal driving, it's your choice whether you want to be a more...How can I say it.. Spirited driver ;).


    The PCM/TCM will learn from your driving habits and adjust the "feel" of your drive accordingly. It will adjust how responsive the throttle is, and adjust shifting based on your style. If you decide to drastically change styles you can clear the adaptives so you don't have to wait so long for the PCM to adjust to your new style.
     
  3. jklotz10

    jklotz10 Well-Known Member Member Relations MOTM Winner!

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    These motors are designed to 'go'. I would think exceeding the recommended RPM limit would damage any motor.
    Lucky for us these cars are designed to save us from ourselves. All these motors have a rev limiter that will not allow you to exceed the set limits and blow up your engine.
    You may be able to get a reprogrammed PCM that has an increased rev limit, special refined tunes for A/F, timing etc, but I don't know if it's available for 2017's yet.
     
  4. KVChallenger

    KVChallenger New Member Site Supporter Level 1

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    I asked because as I read it in the owner's manual, the 300-500 mile break-in for 6.4l is the time to be spirited. It states to "exercise the full RPM range and use the wheel shifters" (Im paraphrasing).
     
  5. SolApathy

    SolApathy New Member

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    6.4L Engine Break-In For vehicles equipped with the 6.4L use the following engine break-in recommendations: 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 160 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 (160 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 (paddles or gear shift) 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 mi (2414 km): • Do not participate in track events, sport driving schools, or similar activities during the first 1500 mi (2414 km).



    Our manuals are pretty detailed. This is the recommended break-in by the engineers for the 6.4. At your mileage it is recommended that you don't "romp" on it, but they want you to sustain higher RPM's.
     
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  6. redvettx2

    redvettx2 New Member

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    My break in procedure. 4 blocks from the dealer. 2 lanes up a hill a that merge into one and then onto the freeway. Toyota Tundra with a V-8 thinks he is going to blow past and beat me to the merge. "Everyone wants to race the black Hemi". I had already launched in first gear and Capt. Tundra is a length ahead of me and 100% into the throttle. Ok Show Time. I bury it in 1st gear and have great hook up as I was already rolling pretty fast. Redline came up pretty fast on me and did a full power shift into 2nd. The All-Season Pirelli's did not like the 6400 power shift very much but still found enough traction to jump past the now struggling Toyota. As Black Betty had her nose up high and was now pulling very hard towards in 3rd over 5000 RPM's to check on the location of Capt. Tundra as I
    was on the merge point now. I checked my rear view mirror and there was Tunda Boy in his lane just going past the darkest, deepest set of set of double burn out patches that had to be 80 to 100 ft long with nice elongated S. I thing the rubber was still smoking. I big small crossed my face and thought "Ya you weren't going to do that in the Audi S6". Break in procedure 1 completed.
     
  7. KVChallenger

    KVChallenger New Member Site Supporter Level 1

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    No doubt there is disagreement on the net about break-in but since Ive been on the fence for a while now I follow what's in the manual. Ive never kept a car for more than 80k miles anyway so whatever. Will the Challenger be something I keep forever as it's an instant classic? Who knows. Typically cars wear out from all the other components before the engine anyway. Break-in is about more than just the engine anyway.
     
  8. TheOldGuy

    TheOldGuy Will Fabricate Anything For Space Shuttle Ride Site Supporter Level 3 MOTM Winner!

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    "Why would the engineers that designed the engine know anything about proper break-in?" Asked sarcasticly...:D

    -John
     
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  9. Hajo

    Hajo MOPAR owner since 1965. Site Supporter Level 4 Site Supporter Level 2

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    Always pay attention to the road, the speedometer and the tach. I changed the rear end in my 65 Plymouth sport fury years ago. It had a 383 with a 4 speed naturally. It was a great looking convertible. But it was a boat. Heavy. So I changed the rear end for more stoplight to stoplight speed to a 433. Mistake. No rev limiter then. I actually pushed the 383 to the point of floating many times. The last time I did it sounded like a shrimp boat (kathunkkathunkkathunk) I nursed it home at about 12 mph shut it down. Never started again. Spun mains. Red Lines. Pay attention to them! If you push your car to the point of floating, you've not done a very smart thing. Your engine can turn into a paperweight.
     
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  10. TheOldGuy

    TheOldGuy Will Fabricate Anything For Space Shuttle Ride Site Supporter Level 3 MOTM Winner!

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    The 429 in my Mustang would "lay down" at 6700 RPM. It was like a built in rev limiter. It was just the way the cam, lifters, and springs all worked together. Plus, there was good piston to valve clearance in that engine. I also ran a shim between 2 head gaskets because of the 671 blower on top. We did that back in the 60's to avoid having to buy dished pistons that were real expensive. I just used the Ford factory forged stuff. They were just a few $$'s more than cast in those days.

    -John
     
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  11. redvettx2

    redvettx2 New Member

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    They also have the manufactures interest as top focus. Not yours. I have broken in many engines over many years. In fact had friends who bought the exact same motor and we broke them in different. I am of the break it in how you plan to use it mode. I don't mean wide open for 2 minutes before 500 miles but drive the car. I am talking about motorcycles, snowmobiles and cars. Mine always ran harder and longer. If you find a weak engine I want it blow early and while under warranty. Not 50K down the road like my buddy. And I am talking modern motors too. Wife had a MB 350 SLK. I never drove it at first. Smoked like a 2 stroke and burned a quart of oil every 500 miles from new! Rings never got seated in because she never drove it hard. MB replaced the car. I broke in the second one hard. It was dam fast and was a great car and never burned a drop. Why. Oil from the factory was 0W30 Synthetic. They had problems if that motor wasn't run hard at break in to seat the rings.

    What over 4 years of building motors, racing and wrenching has taught me. Seating the rings and breaking in a motor are keys to getting a strong, durable hard pulling motor. Seen it to many times. Buddy would not go over 3000 RPM for 500 miles. I ran mine hard through the gears many times using the whole rev range and letting her cool down and then heat back up. Heat cycle the engine just like you should your tires and the same way you bed your brakes. Buddy's identical engine never saw anything but my taillights and his blew up at 42,000 miles (Out of warranty) and we rebuilt it. Mine I sold and it had 121K hard miles and ran for years after. Was a parts running car for a junk yard. They said it finally dropped a cylinder but ran on 7 and refused to die.

    Break it in how you please but understand who wrote the manual and why. Why do you think they added the clutch delay value to manual transmission cars. Your protection (Clutch is wear item) or theirs (Drive line has warranty)?
     
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  12. KVChallenger

    KVChallenger New Member Site Supporter Level 1

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    Thanks for the replies all. Now, on the opposite end, does it stress an engine to run at too LOW of RPMS? My 2015 Bighorn 5.7 and now this Scat 6.4 seems to drive around 1k RPM when Im just cruising and it feels almost too low, I feel as if 1500 is the sweet spot for just light cruising.
     

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