Hey everyone!

So about 6-7 months ago I blew my 4.7 at roughly 145,000 due to oil sludge from venting issues and/or the supposed heat issues causing oil break down yata yata etc etc..... Whatever the cause, I'm not going back to the 4.7 unless someone drags me kicking and screaming.

That said.. I have a friend that was able to hook me up with a 04 HEMI with 84,000 for $1700 before core exchange through the company he works for. The engine is "here" but I don't have it HERE yet. Should probably have it by this coming weekend if I can get a truck to pick it up.

Not gonna lie, I'm somewhat nervous about this swap as I've seen all the threads on the quad cabs but I don't think I've seen any done on a sport, and I know there are differences between the two that may make things interesting for me. The quad cabs have the steering rack mounted on the front side of the cross member where as mine is on the rear. Not sure what that will affect in my case. Also, I'm currently running as a 4x4. I'd like to stay that way but I think the diff is going to interfere with the engine. Might have to drop the diff and run 2 wheel for a little bit until I can find a lift kit to make everything (and everyone) happy.

Another huge debate going on in my head at the moment is whether or not it would be easier to get the 04 harness and computer or would it be better to try to use the 4.7s harness and ECM??

I'll take whatever help I can get on this one. And I'll try to get lots of pictures for everyone as this project commences.

 

I think you are gonna have to ditch the ifs for a solid axle. Which is better anyway. Good luck on the swap keep us updated

 

Went and picked up the engine this morning. It came with a smaller harness just for the engine itself. I was surprised that quite a few of the connections on the HEMI are the same as the 4.7 (oil pressure, coolant temp, injectors, and possibly some others). Still debating on whether or not to use the matching connectors to my advantage and keep the 4.7's ECM and harness or swap to the HEMI's ECM/TCM and harness. If I stay with the original wiring I just have to interface the engine, but if I use the HEMI's then I have to interface the engine and ECM/TCM to the truck.

Any thoughts on this?

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You are going to have the use the hemi ecm. So just the hemi wiring since thats the most important part to get it running. You will have to get wiring schematics and compare them to the hemi harness and figure out when needs spliced in a so on.

 

Yeah, that is kind of how I was leaning. With the throttle being fly-by-wire and the EGR valve it would be a pain to stick with the 4.7 ECM. My only concern then would be how to interface the HEMI's computer to the console. Is it really as simple as splicing wires together? I would think that there would be some sort of communication issues between the computer and the instrument cluster???

 

I dont see why not. Nothing would change. You would be running wires for temp,oil pres and a few other things. I never did a totally different engine swap so its hard for me to say. I know there was a guy or 2 on here that did it. The one guy had a yellow dakota. Here is he on youtube not sure of his name on here

 

From what the manuals tell me (wiring diagrams) the Dakota uses one single physical wire (not a cable) for communication, that connects the ECM, TCM, ABS, air bag system, OBDII port, and instrument cluster together. I'm really hoping that the HEMI's computer communicates with the instrument cluster properly.

On another note... We put the engine in for a "test fit" today. It was getting dark pretty fast so we didn't have much time. From what we could tell it appears that the brake booster may conflict with the coil pack on the 7th cylinder. It may be ok once we can fully lower the engine down but currently it's pretty tight. Also, the oil pan is in the way of the front differential and possibly the steering rack. Once again, we need to get the engine all the way in to be sure on anything, but in the mean time I'm looking into alternative options for the oil pan if push comes to shove.

Does anyone know of a way to basically remove the oil pan from the engine? Can I somehow get rid of the oil sump so I can get the clearance I need? I'm researching dry sumps but I don't want or need the race car style systems with multi-stage pumps. I just want something like a partial sump (maybe just deep enough to clear the crank) and use a scavenge pump to pull the oil to an external reservoir that would feed the engines oil pump??? Does this sound reasonable/doable?

 

Engine is now sitting in the truck with the mounts tack welded in position. We tried mocking up the oil pan to see if we could get it to fit around the front diff but it would have ended up losing 3-4 quarts of capacity which I don't see as being a very good thing. The final consensus was that I will run a "dry sump" type of system in order to keep my front driveline (and it should be better for the engine). Basically, we will cut the sump off the oil pan and weld on some plates to angle down to a drain hole where the oil will be picked up by a TurboWerx Exa-Pump and pumped into a 5-6 liter storage tank. A second Exa-Pump will act as the high pressure side and pump into the engine where I have some plugs by the oil filter for hooking up aftermarket equipment. The engine's oil intake tube and pump will be removed leaving the engine only with the electric system. The pumps will be set up in a way that as soon as the ignition switch is turned to the on position the pumps will turn on. To keep the engine from being damaged in the event of a oil system failure, a pressure switch will be installed on the high pressure side so that until the oil system reaches a certain pressure, the truck will not be able to start, and if while it's running the pressure drops (pump failure, line break, etc..) the switch will disengage the ignition system shutting the engine down. The pumps are rated for 10,000 hours of use so I calculated that at 2 hours of driving every day of the year, thats 5000 days @ 365 days a year, it comes out to a little over 13 years. That can probably be derated a little bit and call it 10 years. Sounds pretty good to me either way. And like I said, I'll put a pressure switch on the high pressure side so that if the pressure drops below say around 20-25 psi then the engine will automatically shut down. I like this configuration because the system will act as a pre-oiler since it builds up pressure in the engine before it allows you to crank the engine over.

 

sounds good to me. We use a similar priming/oil pres circuit. Can spin the motor over w/ ign switch on, but until there's 70psi of oil pres, ign itself stays off.

 

I don't think wiring will be a problem...the 04 hemi ECU and 02 dakota 4.7 ECU are likely similar enough that you can use the correct hemi ECU, and the communication bus won't know the difference. The only potential thing I can see happening is the system detecting a VIN mismatch.