Bear with me -- this requires a little background.

Appropos of the "cracked Cummins" thread earlier, and the comments made on TDR about the dreaded #53 block that cracks from cavitation and 6mm coolant walls, I was curious and did some checking. I used to live in Detroit, where a neighbor was a Chrysler R&D exec. We remain friends and exchange a lot of e-mail. He has nothing to do with the truck division or the Cummins relationship, but he "hears" things from time to time.

Last night I mentioned the #53 block issue, and the Cummins rep.'s response quoted on the TDR thread. He got back to me this afternoon with a curious story.

It seems that for various reasons having to do with end-of-the-model-run scheduling and unforseen equipment breakdown, Cummins couldn't deliver a quota of engines to the DC assembly plants in late January and early February of 2002. They faced a hefty penalty that was built into the contract with DC, so they agreed to ship a different version of the 5.9L for three or four weeks until they "caught up." That version has heavier internal components -- bearings, rods, oil pump, etc. -- and can be identified by some sort of mark near the small "56" under the oil filter assembly (opposite the larger "56" stamped under the injector pump). I don't know what the mark is, and my friend isn't clear, either, but he said he'd ask around. Presumably this particular engine was designed for a heavier-duty cycle.

I'm *not* claiming that this is accurate information, but I am curious as to whether anyone has heard anything similar. My own block has a series of letters stamped near the small #56 under the filter assembly, and the manufacturing date is in February 2002 -- so I have a special interest in spiking or confirming this rumor. The parts people at the local dealership claim no knowledge. "Could be," one of them told me. "I know something like that happened in 1993," another guy said.

Thanks!

GP

 

FYI, some further info. from different people and a couple of sites on the web, concerning the #56 block issue -- again, I make no claims on accuracy, just that this is what I found or have been told: <br><br>Apparently, the #56 block is the heaviest block sourced to Cummins by TUPY, a Brazilian supplier. That's from three different sources; two sources claims that it is the heaviest block ever used in the Ram-bound 5.9L engines. One source claims that the #56 can undergo more rebuild cycles than other blocks. Another source claims that the blocks used in the '03 5.9L's are actually lighter that the #56. (Is there a block-stamp on the '03 CTD's, a different number than 56, perhaps?)<br><br>All sources claim that the internal components used in the #56 block are the same as components in other blocks, with the exception of the pistons, which are functionally-specific to certain models. However, my friend from Detroit is still being told that certain components -- the oil pump and the main bearings, evidently -- were sourced from a different supplier in January-February 2002 because of scheduling and manufacturing downtime problems. He's also being told that they were of a heavier design. I can't find any corraboration for this information.<br><br>I dunno. Perhaps it's a matter of different metallurgy from a different manufacturer. Or -- more likely -- it's just a rumor. <br>Guess we'll see at some point -- hopefully far, far down the road.<br><br>My thanks to GendoThunder, Pourindiesel, Rawlins, and Ahab. <br><br>GP <br>