Engine Knocking - 6.4L / Octane ratings

Discussion in 'Challenger Mechanical Problems Forum | TSB's' started by GoFast, Nov 25, 2019.

  1. baccaruda

    baccaruda Full Access Member

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    anybody have any ideas really where this noise is coming from , as such is it fuel injector noise or is it somewhere in the valve train? surely someone knows , "lets hear it from the mopar techs"
     
  2. STEVEN NIX

    STEVEN NIX Active Member

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    get a diablo sport I3 tuner and run a lower octane tune if you don't want to use the higher octane or can't find it. with the canned tune you also have the option to pull some timing advance out with the i-tune. https://www.hemifevertuning.com/Tuning-Accessories-Compliments-s/48.htm this sight sells tuners and custom tunes, good luck. p.s. if you hear a true ping, the knock sensors are already signaling the pcm to pull max amount of timing out and you are losing power there.
     
  3. synoptic12

    synoptic12 Full Access Member

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    As far back as I can remember "Chrysler's have always ticked".
     
  4. GoFast

    GoFast Active Member

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    I did 2 things that made a huge difference: I dumped a bottle of Techron in the gas tank and a bottle of "Restore" in the oil. There is still ticking but its 75% quieter. I think the Techron cleaned some gunk out and the oil additive is helping lubricate the engine. My guess with the remaining tick is either leaking exhaust, noisy valve train, or the fuel injectors being noisy. Car seems to be running fine for now and I can accept the amount of tick currently. It was excessive before and the fact that I was able to make it quieter shows something was wrong. I might run a fuel injector cleaner through a tank and try some other things to get more lubricity in the system. Need to do some homework on that one.

    I know only use Chevron 91 (in California 91 is the highest grade fuel unless I drive 30 miles to the closest race gas station. Not doing that every time I need a fill up). As long as I use Chevron I don't have the need for an octane booster. Not sure if it's because of the Techron or just because they have better quality gas than the other places I was going. Maybe lower ethanol%? From what I have read the Hemi engines have higher lubricant needs in the valve train and fuel injectors and the ethanol is not good for them.

    I can't believe that these engines have been around sine the 70s and the tick has never been fully figured out. At what point do I bring the car to a mechanic? Sounds like the dealership would be no help.

    Quick questions: is it normal for the Scat Pack exhaust to make noise when cooling down? It clicks/ticks when cooling down after I have been driving for a while and the car is off (different sound than the ticking when running). I had a Dodge Dakota with the 4.7l and it did the same thing. Only 2 cars I have owned that did it. (Between my wife and I, we have owned over 10 cars, many different brands.)
     
  5. Larry St Denis

    Larry St Denis Full Access Member

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    Exhaust noises when cooling down are normal, as the metal cools it contracts. The 392 requires 91 octane and I would only buy top rated fuel from reputable sources. Also the recommended oil is pennzoil ultra platinum 0W40 full synthetic. Do not use any additives.
     
  6. Larry St Denis

    Larry St Denis Full Access Member

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    Mobil 1 website says that they have no products suitable for 392 engines.
     
  7. 70-426_10-SRT

    70-426_10-SRT B&E body lover

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  8. GoFast

    GoFast Active Member

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    I am living in Portland, OR now. We have 92 here. Not sure if it’s any improvement.

    The “knock” I was hearing is mostly gone now. It’s mostly impossible to hear over the normal engine me noise. I did a lot of research and it’s possible the noise is not dreaded the lifter knock but just normal valve train noise. If it doesn’t get louder I won’t worry about it. I have an extended warranty.