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Discussion Starter #1
2004.5 Engine Changes

Changes made from the former 305 horsepower product in
order to produce the new 325 horsepower engine that meets emissions
requirements for all fifty states.

The primary means to control emissions on the new engine are inside
the combustion chamber. Exhaust gas recirculation (EGR) is not used.
This change represents a major advance from the interim approach, with
use of EGR, taken in 2002 to meet federal EPA emissions regulations
for the medium-duty truck market with the B-engine. The engine system
becomes significantly simpler. Fifty-eight new part numbers have been
required to implement EGR as a part of the emissions strategy. Only
seven new emissions part numbers are needed for the new approach used
on the 325/600 engine. A diesel oxidation catalyst (catalytic
converter) is employed. The pilot injection/primary injection strategy
has changed significantly. Formerly, a small pilot injection was
followed by the larger injection event; at higher loads and above 2000
rpm, a single injection event would be used. In the new engine, two or
three events are used. The pilot injection is larger, and when under
power a post-event is added. These events are part of the emissions
and power strategy, as well as a means to noise reduction. The engine
control module now contains 550 kilobytes of code for engine control,
while the previous 305 horsepower HO engine used only 350 kilobytes.

The Cummins noise control strategy includes carry-over of the
straight-cut gears from the previous HO. The Bosch CP3 high pressure
fuel pump is quieter than the former VP44 and P7100 injection pumps,
which suffered noise-producing torque-reversals. Rubber isolators have
been added to the valve cover hold-down bolts. Overall, the engine is
a little quieter, with less rattle and a deeper tone.

The new cylinder head has revised ports with less swirl. High-cobalt
stellite valve seats are used with high strength inconel valves. The
forged steel connecting rods with cracked-cap technology are carried
over from the 305 horsepower engine. These rods pass exactly the same
strength and durability tests as the former, machined cap rods, while
providing more rigidity than the former units. The exhaust manifold
material and shape has been slightly revised for durability, and
multi-layer gaskets are used between the manifold and head. The piston
bowls are slightly more open. The cooling passages for the piston
rings are carried over from the 305 horsepower HO engine.

The turbocharger remains an HY-35, but with a new, larger compressor
wheel and housing for increased air flow. The wastegate has an
electronic controller to better match boost pressure to engine needs
for optimized emissions control. The turbo shaft bearings have small
oil reservoirs under them to improve oiling on cold start-up. The oil
drain tube is flexible steel, replacing the former system of two rigid
steel tubes connected by a hose with two worm-drive clamps. This oil
drain and the new exhaust gaskets were developed as a result of their
successful use in heavy-duty engines.

Engine testing included 22,000 hours on the dynamometer, much of it at
full power. For example, a standard Cummins engine test involves
running the engine at full power for one thousand hours straight.
Other testing involved the equivalent of five million miles of
driving. Two such tests were the Lap of America and the Lap of
Indiana. The former test is a run of 50,000 highway miles with the
truck loaded to its gross combined weight rating. The latter test is a
run of 100,000 miles at 4,300 miles per week, at slow speeds with the
vehicle loaded to its gross combined weight rating.

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Wow,


I gotta check out the New Cummings when it arrives at my local Dodge Dealer.


They have one on order, maybe I can snap some PICS when it arrives.





T
NY
 

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Thanks Hoot. It was so fascinating that it would be sacrilegious for me to make any 'smart' remarks about computer controls. Then I sort of wonder how this 'cat' works and if it restricts the exhaust. Wonder if the fuel mileage will be negatively affected by the changes?


The overall impression I leave with is an appreciation of them finding a simple, strong approach to emisions and then testing the heck out of it for long periods. Cummins sure seems hard at work to continue it's reputation.


On that reputation issue it always mystifies me to read posts from people continually citing the loud engine noise from older Cummins engines. Man, three years after those louder engines ceased to be built, those dumb people still show their ignorance on the issue. That's a reputation Cummins just can't seem to live down.


All in good time. If it's a spade, call it a spade.


Edited by: captainmal
 

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Im kinda disapointed the Cummins quited there engines down. I love the loud chatter of the Cummins engine. None of them V8's had the sound of the big rigs or tractors. The chatter was there trade mark if you ask me i can tell a Cummins comeing down the road easly with out looking from a ways off. Now Ford holds the spot for the loudest engine I think
 

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A member on the TDR website just picked up his new Cummins 600. He said it's awesome. And quieter than his '04 HO Cummins.


MikeyB
 

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Discussion Starter #6
I hope they continue to have success with the newer versions of the Cummins.
 

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Yes, and lets see that new V6 Cummins in the F150 too! IIRC, Ford is suppose to announce that contract win within a month.
 

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i wish the dmax was as simple under the hood as cummins...guess you cant have everything
 

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I HOPE THEY KEEP GETTING BETTER SO WHEN I GET SICK OF THIS MAX I GOT I AM GONNA GET A CUMMINS
 
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