So what about cam failure, piston jets falling out or rocker arm breakage?
Out of all the ford dealers I've worked with and all the forums I've read (I'm on a number of powerstroke forums) the majority of the cam failures and rocker arm breakages occur in modified engines.
If you're doubling the HP of the engine and not expecting something to break, then you have a few screws loose yourself. Easy as that.
My failures I've had in my 6.4L with 90k on it:
1 stuck injector (Probably my fault, long story.)
1 Transmission temp sensor
1 Wiring harness on the high pressure fuel line. (Recall on Job 1 trucks anyways.)
1 EGR (Have since deleted it. Was my fault to begin with, running a tuned truck with EGR still on.)
1 Coolant temperature sensor failure
x3 Pulleys - 1 requiring a belt replacement. (None of them stopped the truck from working. I took it in when I had time to put it down. The squeek was just annoying and it was under warranty. One I fixed myself, and one they replaced because it was starting to go)
1 Anti-freeze line split. (Cheap chinese plastic in a high temp area? Go figure.)
Truck has been in the shop 5 times total in it's life with me - 4 years. The majority (Since 22k miles) It's been tuned. I expect sensor failure and I expect plastic parts failure. Lets face it, every manufacturer builds stuff as cheap as possible. Especially wiring harnesses, plastic lines, etc.
Even the old 5.9's had some issues - look at the 24V 5.9's burning up ECM's, anyone want to talk about that?
Thing to think about. These companies (Ford / Dodge / GM are all in the same boat) have to respond as fast as possible to EPA requirements. The 6.4L came up in under 2 years development, the 6.7L came up in just over 3 years development. You cannot tell me that these companies have enough time to properly stress test these engines under all conditions. I know they try, but there is no way. You're not seeing engines develop over time like you used to. Look at the old ford 7.3 or the old dodge 5.9 - they took 5-8 years to develop the engine before it was finally released. These companies have had respond to: USLD, 3 different series of EPA emissions, and now they're looking at Heavy Duty CAFE standards in a few years.
No one knew the long term effects of ULSD, or all the different grades of ULSD sold across the united states. No one knows the long term effect or urea - and let me tell you, there are PLENTY of issues with urea. You're hauling around 90+% water - what happens when the heating element in your urea tank goes out, and you're in 0 degree weather? Want to talk about thousands of dollars worth of damage and a real dead truck?
Anyways, my point is with any new engine, these manufacturers don't have enough time to properly test the engine. If you want a reliable, fuel-efficient engine, without the quarks of the new diesels, prepare to do off the book stuff. Or, you're just going to have to deal with the failures of the new engines. It's becoming the same way with HD engines in semi's.
Most of the fuel system issues are caused by people not changing their fuel filters. ULSD is a horrible fuel. You have to change BOTH fuel filters in 6.4L engines, every 10k miles or less. (I change mine every 7k) or else the High pressure fuel pump WILL die.
As for pulling the cab off - it's actually easier then it seems, if you know what you're doing. A proper tech can have the cab off in under an hour. Alot faster then pulling the front clip off a truck... Also, it's a lot easier for the tech to work on, instead of climbing in and out of the hood 1000x times. They can just step on the frame and lean over the engines. Most ford techs I talk to actually like it, vs pulling body panels off, etc. There are a few tricks to getting the cab off, the biggest one is heating a wrench up and bending it, so you can use an impact on the cab bolts vs. wrenching them off with a ratchet. This saves about 2 hours time.
