Hello all, I've been lurking here for a while ogling all the cool stuff folks are doing to their X's...lot's a and lot's of great information and ideas around! Thank you!

So, I'm looking for both technical advice and opinions here. Here's my current setup:

Early 2003 6.0L Ex, 256,xxx miles, mostly stock with a few longevity mods:

Monitor, to include EGT
Remote bypass oil filter
Coolant filter, running NAPA Gold ELC
Previous owner took care of the EGR
Opened up exhaust
Stock suspension/tire size

She's my daily driver and used to tow a 19' runabout just about every weekend in the summer and a 28' TT for some long weekends and at least one long trip a year (~10 days).

I've been contemplating swapping to a 12V cummins with a manual transmission next fall. However, I've recently come across a running Cat 3116 at a rock bottom price, and I mean rock bottom. I can do most, if not all of the work myself and have the tools necessary. Anything I can't do, I have someone that can (driveshaft work, for example).

Here's the issue: The stock 12V and the 3116 are relatively close as far as Hp/torque. The 12V weighs a bit more than the 6.0, but the 3116 weighs 500 pounds more. My concern is I'd be loading up the front of my X (even with suspension mods to hold the weight). I'll gain a little bit back from the transmission swap, but not that much (with the 12V, it's basically a wash, total weight).

Is it a safety concern, even with a modified suspension? (this is by far what keeps me up at night when I think about stuffing the Cat in)

Anyone have opinions one way or another on either of the two engines? (12V is MUCH more readily modified if I so desire vs. the Cat)

Where should I start with the front springs? F-450/550/650? I figure the top leaf will hold the brunt of the weight, but are the larger truck springs longer (in other words, would I have to modify the entire set up, to include new brackets on the frame?) Keeping in mind that I'll also be adding a bit of weight up there when towing the TT.

Aaanndd...GO! (thanks in advance!)

 

The F-450 (W code, 5600lbs per pair) and F-550 (X code, 6000lbs per pair) are the same length and width as our factory front springs. I am running X codes (they also came on Super Duties with the snow plow prep package) with another leaf added to the packs, and that's on my lighter than a PSD V-10. I did mine for the additional ride height as much as wanting a firmer ride, they delved both.
With the TT hitched up and the WD hitch adjusted correctly the goal should be to return the front axle weight to it's unhitched weight, not really to add any extra weight. My fancy pants Hensley Arrow hitch has the largest spring bars it can hold at 1400lbs and my TT's TW is a little higher than that so I tow with about 200/300lbs less up front than solo. Of course the dynamic loads do move around a lot while under way and adding a trailer into the mix will have more weight shifting around as you drive, so the front can see higher loads at times.
As far as deezle choices, I aint got nottin to add, I favor spark plugs over glow plugs.

 

From a cost standpoint, you would be crazy to do the 3116. The 5.9 has been done a million times over. Everything you need is easy to find. With that said, my vote is for the Clatterpillar.... how KL would that be ?

I'll assume you have done your homework, and already know the 3116 doesn't have a reputation of being over built. I've never owned one, but have driven a few and I felt it was an adequate engine. I did own a 3126, and put nearly a half million miles on it before I sold it.

Curious what trans you are using ?

As far as weight, personally I wouldn't lose sleep over it. Lots of superduties running around with plows, winch bumpers etc. I might try to move what weight I could back toward the rear. Maybe starting with mounting the batteries on the frame rail, or something similar.

 

Tom, thanks for clarifying the WD weight shift. I tend to think of it as moving weight to the front axle, but it's not really doing that. X codes sound like the way to go, and don't seem super expensive in the scheme of things. Would stock tire size look weird though? Seems like folks are getting a little height when putting on the X codes. I may look to go a +1 on the size. We'll see.

IMASAP, it's (believe it or not) cheaper to go with the 3116. I can pick it up for $200 (the guy was gonna haul it to the junk yard). I haven't heard it run yet, but by Saturday I'll have it nailed down. I have a 12V locked up as well, but it'll cost me $2500 (for the whole truck). I'm thinking an NV4500. I have stock gears (3.73) and don't plan on changing them. I figure any transmission can be "built" as heavy as you want with enough money. The NV5600 interests me as well because the top gear ratio is close to the 5R. I'm shooting for enough "power" to be able to get up and go with the TT, but I also want efficiency (and not cranking a ton of R's at 70mph). My dad built 2 dodge ram 1500 4 doors on top of 3500 frames/drivetrains with stock 12V's, 3.55 gears, and the NV4500. they weigh about the same as the X and pull 25K down the road really well. I've driven them, and I like the way they feel as far as the shifting, power, etc. The G56 is probably off the table due to gear ratio in 6th gear. Originally, the transmission choice was because the 4500 was the cheapest. Now that I've found the Cat, I may go back on that. They all have their pros/cons I guess. Any leanings one way or the other? Oh, and I plan on keeping my existing transfer case, along with the electronically controlled 4WD. Haven't figured out exactly how that'll all go down yet, but I'm getting there.

For sure the Cat would be really cool....I haven't found anyone that's done one in an X. I think there's been a couple F-350's out there, but they're few and far between. One good thing about the Cat is it's cheap. I figure if I don't like it or it doesn't do what I want it to do, the 12V is always an option. Supposedly, the 3126 is the same motor, but 5mm bigger on the bore. I haven't confirmed that with Caterpillar. Downside to it, is working on one isn't nearly as straightforward as the 12V. It's mechanical, but that as far as it goes. Injectors are timed off of #1 injector, and it takes special tools to set them, and they're finicky. Set up correctly, they work.

 

I have no opinion on what you should do with your money but...the 3116 was mechanical injected engine and you had to know what you were doing to adjust the "rack" on the top end of that motor. The 3126 a newer version and is a heui motor like the 7.3 PSD. Neither were considered a fantastic engine....not junk... just not as well thought of as the b5.9 12v. They were just Yellow and expensive. I may have some service manuals laying around for the 3116 and the 3114(4cyl version) if you decide to go down that road. If you do let me know.

I hope this help alittle.

 

What's the issue with the 6.0 engine that you are trying to resolve? If there isn't an actual issue you are trying to work around I would go with what ever you think is best. If there is something you are working against with the 6.0 I would personally go with the 12V as it's a proven setup with a ton of aftermarket support available.

 

Jeremy, that's what I've seen in the bit of research on the 3116. Not the easiest fuel system to deal with. Supposedly when they're set up correctly, they work just fine. They (like most) had runs of issues with that engine. If I go that route, I'll absolutely be in the market for manuals.

Copsey, there are a few issues cropping up with the setup I currently have. Nothing earth shattering (#5 cylinder out of balance, intermittently) when it gets cold. I've had the code crop up on occasion, but it seems to go away with a little "drive it like you stole it" once in a while. I'm pretty convinced that injector is starting to go. I run archoil all the time and occasionally run anti gel/cetane boost. I've also run lucas in my fuel. I change filters religiously and always buy fuel from one of two stations that I know goes through a ton of it (high turnover). The other "issue" I seem to be having is an apparent slip/no slip in my transmission at torque lock. Again, only when it's cold outside. Torque lock is kicking in about 45 mph and all the way up to 60 mph, it feels like it slips out and back in repeatedly. No excessive clutch material, filters and fluid have been changed and still look good.

Bottom line is this: I want to be able to comfortably tow the TT/boat without much worry. To do that, my options (at 256,xxx on the clock) are to rebuild everything I have with add ons like ARP studs and a chip (6.0 stock is a bit of a dog towing, IMHO), to include the transmission (very expensive), go to a 12V/manual combination (still a bit expensive, but not terrible), or now a 3rd option of the Cat/manual transmission (even less expensive, but maybe long term it's not worth the hassle).

I for sure have a bit more thinking to do!

 

I fixed your last post and made the solution much easier for you!

 

Haha! Well done...