The "famous" connecting rod pic

[bmoeller]

rbattelle-



That is the same display that I saw at the Farm Progress Show in the Dodge tent. Pretty neat to see in person.

 

[rbattelle]

I find it very interesting that we talk about the picture all the time on this site and now Dodge is using those rods as advertising materials. I guess someone at DC is reading this site after all! Now if only that person would put forth some initiative to improve the deplorable conditions at dealership service centers!

 

[dseabaugh]

how about this one... .



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Are you sure about these rods? It looks to me like a John Deere, Lawnboy, and a Homelight. :-D

 

[CROW]

I've wondered why Dodge dealerships don't have a display of these rods to show potential customers; makes a powerful point. I agree that the Duramax and Powerstroke rods look like large block gasser rods; nothing appears heavy duty about them. But heck, guess they work. What would be interesting to know is the weight of each rod. Suspect that six Cummins 5. 9 rods would be heavier than eight Duramax or Powerstroke rods.

 

[CJEliassen]

That ship engine produces 100,000 HP and 4,000,000 ft. lbs of torque at 101 RPM.

 

[klenger]

Just to be fair to the other guys, I've never heard of a PowerStroke or DuraMax failure caused by connecting rod failure, but I don't pay all that much attention to their forums either.

 

[nickleinonen]

you sure about these rods? It looks to me like a John Deere, Lawnboy, and a Homelight. :-D

it's probably a BS photochop deal but funny none the less :-laf

 

[David Muench]

As long as my truck has the John Deere rod in it, I'm happy.

 

[Hohn]

Courtesy of Don M-- The new ISBe connecting rod with fracture-cap design...

 

[DPelletier]

Just to be fair to the other guys, I've never heard of a PowerStroke or DuraMax failure caused by connecting rod failure, but I don't pay all that much attention to their forums either.

Well, seeing as how this thread has resurfaced again, I'll throw in my 2 cents worth;



Ken, I applaud your sense of fair play, but I should point out that even if a DM or PSD never throws a rod, the size of the rods (both thickness and diameter) determines the size of the main and rod bearings. The more bearing surface, the longer the engine will last (all things being equal). Of course all things aren't equal; the Cummins has a lower redline further reducing wear. Then we have seven main bearings for six cylinders instead of five main bearings for eight cylinders. Sprinkle in some aluminum heads, bad programming and spotty quality control on the competition's side of the equation and there you have it folks, a clear winner!



Dave

 

[rbattelle]

Hohn,



Excellent pics! That is one sexy-looking connecting rod!

 

[loncray]

Yes, that's a very nice looking connecting rod! Any chance you can get current pics of the ones in the various competitors? I agree with DPelletier - our trucks do have the clear winners - now we just need to convince the unwashed masses of this when they go to buy diesel pickups!

 

[Kiohio]

Wonder what the German diesel engine rods will look like?

 

[El Putzo]

I agree

I agree that the rods and larger journal size of the 5. 9 make it the obvious choice. But the amount of mains??? C'mon guys, it has to be that way. Think about it, in a V8 motor, the cylinders are basically directly across from each other with an offset the thickness of the rod, therefore putting a main bearing between each rod would make the engine at least 6 inches longer and way heavier because of the greater distance between pistons to compensate for the extra mains. Obviously on an inline 6 there is going to be the need (extra rotating mass) as well as the room to put a main between each bearing. So IMHO it is not that Isuzu and Navistar leave out the mains knowing it will be weaker, it just works out that way. Also, in my limited experience with both gas and diesel motors, when and engine comes from together, it is almost always the result of a rod related failure. Not trying to defend either of the two, just pointing out a basic design characteristic.

 

[hasselbach]

great photos, but I think the debate between and I-6 and V-8, and which one is superior is not provable. How could an inferior V8 produce over 6,000 hp for a nitro motor if it is that weak? You could also argue that a too heavy of a rod would be detrimental due to the loads imposed from rotational weight of the item...

 

[DPelletier]

... But the amount of mains??? C'mon guys, it has to be that way. Think about it, in a V8 motor, the cylinders are basically directly across from each other with an offset the thickness of the rod, therefore putting a main bearing between each rod would make the engine at least 6 inches longer and way heavier because of the greater distance between pistons to compensate for the extra mains. Obviously on an inline 6 there is going to be the need (extra rotating mass) as well as the room to put a main between each bearing. So IMHO it is not that Isuzu and Navistar leave out the mains knowing it will be weaker, it just works out that way. Also, in my limited experience with both gas and diesel motors, when and engine comes from together, it is almost always the result of a rod related failure. Not trying to defend either of the two, just pointing out a basic design characteristic.

Exactly.

To be more clear, I am not suggesting that Isuzu and Navistar somehow made substandard V-8 diesels by leaving out some main bearings, but rather the I-6 design is superior from that perspective.

I would give real money for an actual measurement comparison of the main and rod bearing areas between the three motors. Wouldn't be hard to do if'n someone had the appropriate measurements. Someone will undoubtable counter with the argument that the cummins needs larger rods etc. because it is producing the same (or more) power from 6 cylinders rather than 8, but I contend that if you look at bearing area per hp, the Cummins will be head and shoulders above its competitors. So to recap, some of the advantages of the Cummins are inherent advantages of an I-6 engine for high torque diesel engines and some are just because Cummins made a stronger engine.











Dave

 

[DPelletier]

great photos, but I think the debate between and I-6 and V-8, and which one is superior is not provable. How could an inferior V8 produce over 6,000 hp for a nitro motor if it is that weak? You could also argue that a too heavy of a rod would be detrimental due to the loads imposed from rotational weight of the item...

I am not saying an V-8 is an inferior configuration for a 6,000 hp nitro motor, nor am I saying a V-8 is inferior in all applications. Personally, I love BB V-8's. (cool Camaro, by the way), but I believe that the I-6 configuration is better for high torque, low rpm diesel applications and the Cummins is an excellent example of such a motor. You don't see many I-6's at the drag strip for valid reasons. You also don't see too many large V-8 diesels in class 8 tractors or marine applications for equally valid reasons. This isn't necessarily my opinion, it's just the way it is.

Maybe a better argument would be to suggest that lighter, higher RPM V-8 diesels are more suited to passenger vehicles and light trucks than heavier low RPM I-6 motors, and from a driveability and performance standpoint that argument may have its merits, BUT the lower RPM, heavier I-6 Cummins will far outlast the other designs whilst offering superior low end torque. Yes, yes, I know, you only keep your truck until the first rock chip appears anyway. Well then maybe the DM is the better truck for your purpose. When I buy another new truck, I intend to roll this one into my fleet and run it for as many miles as it will hold together. The Cummins is stronger, more reliable and offers more longevity than the other V-8 diesels the competition is using. Again, not because I say so, just because that's the way it is.







Dave

 

[hasselbach]

I'm curious however about all this talk of more bearing surface in the Cummins vs. a V8. My question is, who has personally witnessed the bearing surfaces being an issue on the v8's?

 

[DPelletier]

I'm curious however about all this talk of more bearing surface in the Cummins vs. a V8. My question is, who has personally witnessed the bearing surfaces being an issue on the v8's?

Generally when you get a main or rod knock the bearings are toast on any engine. I guess I have witnessed the bearing surfaces being an issue on V8's as I've seen several wrecked motors with wiped out bearings.

Anyway, all nitpicking aside, you don't really think a DM has a chance in the hot place of outlasting a Cummins on average, do you? C'mon, I know your smarter than that.



Dave

 

[rbattelle]

Here's the current model engine connecting rod comparison:



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