Join Date: Feb 2009
Location: North of Dallas
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Originally Posted by Allpar.com
Bob Sheaves discussed why the system is almost always used on V8s and not V6s:
"An Otto cycle engine requires two full revolutions of the crankshaft to fire all the cylinders. Two revolutions x 360 degrees equals 720 degrees of rotation. Dividing that total rotation by the number of cylinders to have an even firing engine (naturally balanced) will give you 120 degrees, which means that you have a cylinder firing every 120 degrees of rotation. When you take out 3 of the cylinders, you have increased the firing rotation to 240 degreees (720/3), still balanced between each firing of a cylinder. The catch is that you have increased the harmonic vibrations as the rpms increase. Deactivation of four cylinders in a V6 would mean losing the multiple of six cylinders, which intrinsically keeps the engine in primary balance. (The lack of natural balance is why balance shafts are often used in 90 degree V6s and larger inline 4 cylinder engines.)"
I saw that picture, and to me it looked like a heavier chain. How much? Dunno!
Harmonics? Ya I believe it.
Tensioner or Guide? Probably a factor also.
MDS? Contributing also!
Chain? The one constant failure point.
Talked to my Service mgr. today via phone. Said the timing chain broke, and they are replacing the heads also! Asked a few questions, got really nowhere. Will be at their doorstep mon a.m. to take a look and maybe some photos if they've done squat. The service mgr. sounds like a real wizbang!!!!!!!!!
Asked him "why are you replacing the heads? Bent valves?" His answer "Thats what the factory is sending us!" I then asked "Did the valves make contact with the pistons?" Wizbang "We don't have the heads off yet but if there is further damage I will be talking to Chrysler" Me "Don't you f*****g think you should diagnose a little before you assume everything else is alright?" Wizbang "I'm sorry sir" I just told him I would see him first thing monday morning.
LAST post by your favorite a$$hole, just to give the youngsters a quick, easy demo, that ANY of you that have an OHV, pullcord start lawnmower, of how MDS works, hokay?
Fire it up to be sure it runs. Now, remove the valve cover, if you dare, now, remove BOTH rocker arms, again, this is very advanced, YOU may never get it running again without calling a professional. Now pull the cord with no rocker arms...what IF the intake rocker arm was operational just long enough for the first gulp of 14-1 air fuel mixture, fired it as usual, THEN the rockers were off.....that air/fuel charge exploded one time, peak cylinder pressures rose ENORMOUSLY and then, they NEVER left the cylinder, which now has no rocker arms and YOU are TRYING to yank that cord to pull it through the next rotation with what started as maybe 175PSI & went maybe 10.5x that when the plug ignited it that one time before the rockers came off...think...no, go try the experiment, if you have a wrench or two & go ahead & show EVERYBODY what an idiot this guy is...but don't talk to me about it, I don't know sh!t....
This thread has become more about how MDS functions and why chains break then focusing on the fix to this problem, don't get me wrong, I think we have some great minds on this topic but it's time for theories on how to prevent this disaster from happening to these motors.Ive heard a few ideas, such as - 1) tuning out MDS with the predator- 2) changing the timing setup-3) using autostick. I don't believe dodge will address this mess, so I check in with this thread every day in search of a solution to this problem. So please keep the suggestions coming. Thank you all for your input so far. I do not want to get rid of this car, still hangin on.
Sent from my Autoguide iPhone app
|failure , problems , timing chain|
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