There are some serious voodoo theories going on here. The are quite interesting especially the one about the Challenger having more aggressive factory programming done to the PCM.
Do you have any idea what it might be? I personally think it is most stressed at the transition time, but that is not what the owners of the failed timing chains have said.
Oh, I found a document I had on file here at work, that may be appropriate for a certain poster in this thread. See attachment.
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09 R/T 28J, built 8-7-08, K&N CAI, catch can, SRT scoops, struts, springs, 70 R/T stripes, SRT wheels and tires.
Just to let everyone know, I had this happen at 38000 miles, 2010 R/T Auto. Driving on the freeway and engine shuts off.
I have the Lifetime Warranty and it IS covered. They changed heads, cylinders, the infamous "timing chain", the whole works. Basically rebuilt my engine, and just got it back a couple days ago. Been just a little over a month, and works fine now. I plan on buying the Diablo programmer and shutting the MDS off with all the other perks, because I'm afraid this will happen again at around 80,000 miles. Don't really care about the mileage since my company pays for my gas, and this is my daily driver.
I brought up the Manley timing chain to the dealer when they first told me it was the timing chain that broke, and they said they wouldn't install it only because IF that broke, it would cause the same damage but wouldn't be under the lifetime warranty since it's not their product. damn!
My auto turns 2200 rpm at 70 mph. Seems like I've read comments on the forum about the manual transmissions having a lower rpm than the autos at highway speeds. Since these failures are occuring at this speed, the rpm difference could be a factor.
@ 70mph, the 6-speeds run ~ 1,650-1,700rpm, so its not a big difference in the scheme of things.
The 3.73/18" or 3.91/20" combo is virtually identical, as the 3.91 setup uses a taller tire and the overall ratio ends up being the same.
[18" = 715.8 revs/mi vs. 20" = 703.2 revs/mi]
When going up grades/ passes, you'll be @ 2,200-2,300rpm in 5th, as being at 5-6K' altitude and up a 5-6% grade, 6th gear is too tall for those situations.
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2009 R/T 27J pkg (6 speed MT) ordered 7/17/08, built 10/23/08, home on 11/13/08
A few years back I had to replace the heads on a 02 Dodge Ram 1500 4x4 4.7L. that I had. The Chain that turned the OHC was twice as beefy as the timing chain in the 5.7's
It baffles me as to why the engineers would put such a spindly timing chain into an engine with more HP
Last edited by dodge junkie; 08-03-2012 at 09:51 AM.
A few years back I had to replace the heads on a 02 Dodge Ram 1500 4x4 4.7L. that I had. The Chain that turned the OHC was twice as beefy as the timing chain in the 5.7's
It baffles me as to why the engineers would put such a spindly timing chain into an engine with more HP
If you read the whole thread, it is pretty well covered. It is a space problem, due to the additional hardware for the VVT IIRC.
There was at least one post showing that the Camaro motor uses virtually the same size chain on their similar system.
My MDS is going off with my predator tomorrow. I haven't used it in over a year, so I will have to learn how to turn it off. I hate it though, gas is 4.25 a gallon up here but I don't want the thing to break.
It baffles me as to why the engineers would put such a spindly timing chain into an engine with more HP
Engineer proposes; accountant disposes. Nothing new. This said, and all please bear in mind that I never even stayed at the same Holiday Inn as Chet Herbert, I think that sometimes it can be more a matter of resonance and natural frequency than pure part strength. And it's possible that, say, 2,200 rpm, or 2,275 rpm, or whatever, happen to create a destructive resonance that would never take place at even slightly higher or lower rpms, or with larger or smaller chains/tensioners. You'd think that this kinda thing would come up in testing, especially when as common as highway speed cruising, but maybe they don't put 40,000 miles on their mules doing one specific test.
@ rt2010mm: 38K is right at the average mileage for the failure, going by the numbers listed by raVenX. MDS delete via Predator seems like a good idea. At this point it's still a theory, though, except for a know-it-all or two.
And it's possible that, say, 2,200 rpm, or 2,275 rpm, or whatever, happen to create a destructive resonance that would never take place at even slightly higher or lower rpms, or with larger or smaller chains/tensioners. You'd think that this kinda thing would come up in testing, especially when as common as highway speed cruising, but maybe they don't put 40,000 miles on their mules doing one specific test.
that is as good of a theory as any, hadn't thought of that one.
I used to fly H-34s made out of magnesium, and if the right vibration was set up on landing, they would go into "ground resonance" and basically implode.
A few years back there was a thread on how Chrysler tested their engines for 200k of "durability".
I believe that it was stated that if the engine would "live" for 200k of testing, that 95% of production engines would achieve the same mileage.
The other 5% couldwould fail under certain conditions, and that would be acceptable.
So, I'm sure that Chrysler has some long term test engines with results published in house, but we don't know the test parameters, and what did fail...........and when.
Everyone scowls at that little timing chain, but it seems to hold up to WOT conditions for the 5.7 and the 6.4, and all manual cars?????????
Not a soul on this board has posted that his chain broke during a WOT condition......only cruising at about 70, MDS "on", and then BANG.
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2010 RT "Classic" Automatic
Options: (28M); Electronics Convenience Group; Power Sunroof; and the best $225 option in the world: Detonator Yellow Clear Coat
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