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Discussion Starter · #1 ·
I think what im hearing is Timing rattle. Kinda sounds like a gas car pinging, How much is bad?

While driving at about 40 MPH I can barely hear the rattle. This is with the radio off and windows rolled up.
 

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still trying to decide how much rattle is ok, im under the impression that the even numbers on the smarty are better without fuel mods, mytruck on 5 made a lot of noise, no smoke, now on 6 there is some rattle but it has a constant haze through the gears, so now i believe i have enough fuel
 

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Rattle is good it means you are running sharp timing.
 

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when is it sharp enough to cut the piston in half
 

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I am new to this timing rattle thing. This is my second diesel, my first one was a 98.5 24v that I got rid of as I was buying my new 6.7. That old 24v, man I loved it, was louder than anything I hear today. Sitting at idle, I would have to raise my voice to speak to my passenger.

This 6.7 is quite like a Rolls. I don't like it. Anyway, with the smarty on SW1(30hp with timing) the truck doesn't really sound any different at idle. When I am driving and I get on it, it sounds very similar to my old 24v. I assume this is the timing rattle? Should you ever hear it at idle?
 

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Discussion Starter · #6 ·
Can anyone explain when to know if you can add more timming, and when to stop? Im thinking of bumping my timming up another notch from 3 to 4. Im not hearing any timming rattle, Or what I THINK is timming rattle.

current tune is SW5, TQ2, TM3 RP3, and MP-8 usualy on 100,
 

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No, timing discussions are no longer allowed. Just kidding .I would not try to get it to rattle. The multi- event injection takes away the rattle and I don't know which event gets advanced.... could be all three are moved together or just the middle or some other combo.... man it would be nice to put a P-pump on one of these.Could you imagine the thick,rich, delicious smoke???
 

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Discussion Starter · #8 ·
LOL

SO am I correct in hearing Timming rattle is simmilar to the sound a Gasser makes when it's pre-ignitin/detonation is happening? (Timming too far advanced or poor fuel)

I would also THINK that I would not want to hear any rattle, however Im getting mixed answers.

I thought this was a very simple question LOL
 

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Timing rattle or early ignition is bad for a gas engine because the fuel should be ignited by a spark ......however sometimes gas will ignite from heat alone.... a lot of heat, in a gasser you want the so called "explosion" to be an even burn,... the gas ,when it is ignited from a spark actually burns like a wave in the ocean, it is suppose to move across the piston and the air /fuel mixture expands at a controlled rate and forces the piston down.in a gasser the slower the burn the more evenly the force is applied to the piston during its travel downward , you do not want the piston to have an explosion... you want the energy to be released over a greater length of stroke rather than just a quick explosion and then the piston is only making power for a short while on its way down. More to come.
 

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Now... in a diesel there are 2 things that cause the diesel to burn(combust)..... Pressure and/ or heat. No spark required. This is where things get tricky.... If someone out there wants to correct me please do, but there is a certain place where the piston is located before top center (not sure of the Degrees) where the injection takes place, which I believe the closer to top center you get the more likely the diesel is to explode rather than burn evenly, which is giving you that rattling sound. The difference is a gas engine is not running the materials for the pistons and the cylinder pressures are higher in a diesel ,the entire engine is extremely robust so it can handle this explosion.Its kinda like pedaling a bicycle if you push the pedal from the very top you can get more torque rather than pushing it from half way down on the stroke. I need someone to chime in here and tell us what the air to fuel ratio is on a typical diesel vs. typical gas.I believe diesel expands more than the same amount of gas also, I am not sure. What is the stoichiometric expression for both????
 

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Diesels burn like a candle burns. The fuel mixes with the oxygen as it burns. The timing rattle you hear is when the fuel atomizes with the air and is flashed off. I believe these little explosions are called deflagration. I think that is how it is spelled. Any way I will look for the article that explains it a little better.

A Closer Look at Diesel Combustion
One of the main differences between a gasoline engine and a diesel engine is the type of combustion performed. A diesel's burn is very complex and uses the same principle as a candle, where fuel and air mix as a result of the combustion. Convection currents and turbulence play a large role in how the unmixed (heterogeneous) fuel is burned. A gasoline engine, on the other hand, mixes the fuel and air completely (homogenous) well before its comparatively simple combustion. One of the downsides to injection gasoline engines is that when the piston compresses the fuel air mixture, some of it gets stuck in the imperfections of the cylinder walls. That is why gasoline engines have higher carbon monoxide (CO) and hydrocarbon emissions compared to diesel engines.

Why does the diesel engine sound so loud?
Remember how we just said diesels have an unmixed fuel-air combination? That is not totally true. Some of the fuel does mix with oxygen on the atomic level. These small pockets are like little bombs and are the first to ignite. These premixed (deflagration) waves are known as detonation. This is a violent supersonic flame front, which moves faster than the speed of sound. In the wake of this release of energy, the vast majority of the unmixed fuel burns as a diffusion (non-premixed) flame. So the amount of mixed fuel in the cylinder at the beginning of combustion determines how much noise you will hear. Turbochargers and exhaust gas recirculation (EGR) systems make the diesel quieter.
 

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Excellent ....these new multi event injections on our 6.7's apply the fuel in such a maner that it "cushions" the explosion, so its almost impossible to make one of these rattle.My Smarty programer advances the injection timing just enough that it will rattle a little..... nothing like the older ones though.On my 97 Robert at Shiver diesel advanced my pump timing and it rattled much louder and had a much quicker throttle response.Also these 6.7's have a oil pan that is called a constrained layer design.... I call it plastic.... have you tapped yours with a wrench??? ....it was also designed to make the engine quieter.
 

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i get a little rattle with edge timing but nothing serious, the bad part is advanced timing and high egt's, this combo injects the fuel early enough and hot enough to burn the injector pattern into piston crown and deck, really makes a mess, dont let it rattle to much but watching your egt's is most important, a little timing wont hurt
 
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