TOW RIG OVERHAUL! 2nd time... diesel swap

[Van Gui1d3r #838]

i feel like I've done this thread before... o yea, right here, http://www.gmt400.com/threads/tow-rig-overhaul-need-answers.33946/

ok so the tow rig, it's awesome and all. the 454 has tons of tq and I love the power. but, apparently she's thirsty. it takes a lot of juice, to fuel this power.... yes I knew this before swapping it and I wasn't worried. then I bought a TDI Jetta and have discovered Diesel mileage and surprisingly, the power difference. that jetta chugs up hills without downshifting even with a full car. so I went for a cruise with my buddy in his DMAX and I was pretty impressed with that wide tq range. and then found out he gets 19mpg daily driving his truck and his towing mileage is still12-15 depending on how much he's hauling... my truck gets 8 mpg daily driving and well 8 mpg loaded... if I could get 12-15 average on my truck, I would be ecstatic and with the same or better power than I have now, EVEN BETTER!!!

so I really thought about it and the 6.5l is not an option. they sound like toss away engines. so I looked into 6.6 DMAX swaps. a lot of people complaining about those and the hassle they are with wiring. then my buddy said "Cummins swap it!"... we're no longer friends. plus that seems too easy. then searching I found an article on a C3500HD with a 7.2l cat straight 6 in it... i'm intrigued!!! the article is here, http://www.trucktrend.com/features/...owing-king-with-7-2l-caterpillar-engine-swap/ . problem is, I hear CAT engines are problematic so I searched for something different but close, in which I found a 7.8l DURAMAX (aka Isuzu 6H)... so I research it and struggle to find info but here it is....

1. this engine is massive! too big for my engine bay! 52.5" long... don't care, still want it.
2. they weigh 1400lbs... too much for my truck daily... don't care, still want it(more on this).
3. no aftermarket support besides a chip... don't care, still want it.
4. multiple power versions but they do make a 300hp 860ft-lbs tq version.

i'm in the works of acquiring a 3500HD. for all that don't know about these, it is my truck on steroids from the factory... thicker beefier frame, I beam front suspension leaf sprung(will handle the engine weight with ease). o and these trucks are 15,000lb GVW opposed to my 10,000... DANA 80 rear end... etc... these trucks were the definition of BEAST MODE before anyone ever used the ******* term before.

so my thought process is, acquire said 3500HD, toss the 6.5 on CL, acquire 7.8l take the cab and front clip off, make mounts, cut big hole in firewall for massive engine to fit into, flange floor and firewall for a cover or "doghouse" like in a van...

WHAT ARE YOUR THOUGHTS? please, no thoughts on why not to. the reason to do this is because this engine was designed to haul weight. not to be in a pickup... well i'd like a pickup to haul weight so I guess I need to make it work. I don't get a choice. my fate was determined at birth and that was to always do **** the hardest way possible and then reap the benefits later after blood sweat and tears.

 

[Van Gui1d3r #838]

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this is the truck i'm trying to get

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this is the print on the diesel beast

 

[skylark]

Not trying to talk you out of it but if you are happy with your friends duramax why not swap what you know will make you happy? You don't know how thirsty the 7.8 is going to be.

 

[Van Gui1d3r #838]

Not trying to talk you out of it but if you are happy with your friends duramax why not swap what you know will make you happy? You don't know how thirsty the 7.8 is going to be.

excellent question. the main reason I want to stay away from the 6.6 V8 and go with the 7.8 straight 6 is that the straight 6 is has a lot less wiring. the 6.6 from what I read is a wiring nightmare. they are easier if you buy a complete donor truck.

and second is, the 7.8 was designed specifically for hauling in medium duty trucks like 6500, 7500, and 8500s. trucks like that are built for packing on miles and are typically detuned to last much longer. when I looked it up, guys are "claiming" 10-12mpg in the big trucks that are probably not geared the greatest for miles but more for hauling.

one more reason, I can't find evidence of anyone else doing it so it's an unproven build that would be exciting for me to get into. I figure worst case scenario, I have a truck that gets the same or just a little bit better mileage that can haul "all of it".... it would be the perfect truck for Napoleonitis if that's even a thing...

 

[90halfton]

Fuggit. That will be awesome if you can cram it in there. Cat motors are good motors though. One of the most reliable motors in a 2 ton pickup (that I've drove). What is your plan for transmission? How high are you gonna have to lift it?

 

[Van Gui1d3r #838]

Fuggit. That will be awesome if you can cram it in there. Cat motors are good motors though. One of the most reliable motors in a 2 ton pickup (that I've drove). What is your plan for transmission? How high are you gonna have to lift it?

I have no idea of a trans yet. I really like the idea of a ZF6 or NV5600 but then again, an auto would be a better choice for ease of hauling. but then i'm not very familiar with the autos for such an application like this. I like those sticks because they both have an overdrive and a granny low tow gear. I figure either one coupled with 3.42 or 3.55 rear gears could hold 60-65 mph at 1850rpm which is a magic number for highway cruising and miles. and with the granny low 1st, I wouldn't sacrifice hill starts with a heavy load

i'm not sure it will need a lift, the 3500hd body sits 4-5 inches higher than a standard 3500 which will give it more engine room. i know the engine is only a few inches taller than a 5.9 and I've seen those in our trucks so hopefully there are no issues. i would go with a cowl if i had to but would like to stay away from the body lift.

also, I have no room to bash the CAT motors at all. i'm just going from what I heard about them and it seems theres many mixed feelings about them. the bad rap I've heard of the straight 6 DMAX is just some claim they feel like they are lacking power and that's probably true because some only had 200hp and 550ft lbs tq in big trucks...

 

[90halfton]

Have you given any consideration into how much this engine/trans is going to weigh? Not trying to discourage you be any means, this idea is awesome, but these large diesel auto transmissions are rather heavy, as are the engines.

 

[Chewy1576]

Why are you so fast to dismiss a Cummins? Yeah it comes in a Dodge truck, but they are the best thing about a Ram in my opinion. I still wouldn't buy one to drive myself, but I would take one of those engines in a heartbeat!!! A first gen 12v is dead simple to install and you can still make good power.


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[Van Gui1d3r #838]

Why are you so fast to dismiss a Cummins? Yeah it comes in a Dodge truck, but they are the best thing about a Ram in my opinion. I still wouldn't buy one to drive myself, but I would take one of those engines in a heartbeat!!! A first gen 12v is dead simple to install and you can still make good power.


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i'm kind of against the crossbreeding like that. it's not that i have any problem with a cummins, i just hate the idea in a chevy or GMC. it's just a bandwagon i don't want to jump on. i feel i'm betraying myself enough by dropping the big block as it is haha.

Have you given any consideration into how much this engine/trans is going to weigh? Not trying to discourage you be any means, this idea is awesome, but these large diesel auto transmissions are rather heavy, as are the engines.

yes. the engine is 1400 lbs and as far as a tranny, i'm not sure what i would use yet but this is why i would like to use the 3500HD which is the "missing link" between light duty trucks and medium duty trucks. but remember this as well, a lot of 1 ton trucks have diesel or big blocks that have engines that weigh 800-1000 lbs. couple that with 600-900 lbs of plow brackets and a plow and those trucks exceed what this engine and transmission would weigh....

 

[deejaaa]

i like it.