ISX or ACERT, can't win?

Taken from the org post:

A mechanic at my current company told me the ISX is something to stay away from. Where the connecting rods go through for the wirst pin, it is a tapered area. Cummins is not running a full skirt on there pistons anymore, and this is the 2nd ISX in the shop needing a full rebuild, with only 800,000 KM on the clock. Apparently the con rod bushings wear funny and make to much clearance, and with the pressurized rods, you lose all your oil pressure to your crank and your rods, bye engine.


Here is what kennworth told me when i presented the above statement ,,, for what ever it may be worth to you. My truck is an 03 kw 475 ISX needing an inframe at 891,000 miles which in my feeling would have made it to a million easy if not for running this truck in the oilfields for one year.

Gary,
I cannot comment on where that technician received his information. I can say that we have rebuilt and overhauled 40-50 ISX engines in the last two years and I have never seen one of the engines fail with Mono-therm design pistons and drilled rods in the manner he is describing to you. The issue in your engine is piston ring related, which is a common issue with the two piece pistons and their companion ring design.
The ISX oil pump is built to put out roughly 1.7 times as much oil as the engine needs and the additional flow to the connecting rod and piston assemblies does not impair the flow to the crankshaft. The failures that occur most commonly are piston ring breakage. This can be caused from malfunctioning EGR valves that are not repaired soon enough, extended idle and dirt. Sometimes the failures progress to the point of using enough oil to drop the sump capacity low enough that on a hill the entire lube system is starved and thus rod and main bearing failures occur. Understand though, the root cause of this failure is extremely high blowby and oil carryover from the ring damage not from a connecting rod failure. The piston still has a skirt which is part of the crown or one piece design; it is alloy steel instead of aluminum which resists scuffing and seizure due to heat. It is a tough design that we have had very little problem with except a few ring issues that were caused by what I mentioned above. As for crankshaft, rod and main failures I have not seen one that was caused from what you had been told. Wrist pin and connecting rod failures are far more prevalent with the two piece design that you currently have in your engine.
Each and every current diesel engine has its specific issues that can result in a failure but do not commonly occur.
Hope that helps, if you have any further questions please feel free to ask.
Thank you,

 

Dont know how reliable this is but ive heard up to 5 grand with labor.

 

How much is the single turbo conversion kit from PDI?

 

Manifold and turbo $3625. and up.

 

The only issue I see with the PDI single turbo sway is the engine is gonna lose the low RPM that the ACERT was designed to work in becasue the PDI turbo won't be able to build boost that low. This could effect the intake valve actuators and emissions systems. I have read stories where guys have done the switch and been very pleased, but the stories didn't include any emissions results and say whether the IVA system had been modified or not. Emissions standards are not high on my list of performance gains, but with the different states getting tighter on regulating us one can only plan for the future.

As for price...I got none. I do know that replacing the turbos is something a o/o can do himself, but the bigger project is cleaning out all the new intake tracks. If a turbo suffers a compressor wheel(s) failure then the air-water cooler, air to air cooler, and all the other tubes need to be removed, cleaned, and checked for damage. This is where I see the big increase in price. I can imagine that the air to water cooler could be heavily damaged from a compressor wheel failure since it is first in line with the turbos. Then with the air to air next you have pretty much 2 filters that should keep the majority of the debris contained and out of the cylinders.

 

The last I knew they PDI wasn't really advertising the conversion kits, but they do sell them and will discuss options if you call. To be honest I haven't heard of one compressor wheel or turbine wheel failure...mostly the failures have been with the center section and sealing surfaces. The shaft failures I have heard about have been from lack of proper lubrication. I'm guessing if a compressor wheel were to fail it would be the high pressure turbos wheel which would save the low pressure wheel since its before it. But from what I hear neither turbo really works as hard as a single, so a typical compressor wheel failure may be hard to acheive if the motor is treated with respect.

 

The most common failure is the exhaust sleeves in the head craciking and a peice breaking off, resulting in hot wheel damage of both turbos, $9000 canadian repair bill!! The exhaust sleeves are covered under the ESC plus, so its good to load up the warranty to the 10 year 700 000 miles. I like the twin turbo set up, they were made to be more reliable as pullertruck stated. Look at the mbn, way to high shaft speed and high failure rate. Cat claimed 30% shaft speed reduction with the twin set up. I have got customers running them at 70 psi and not having failures. Would never think of pushing that with a single (not in normal daily driving!!)

 

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