: Cummins 5.9/NV4500 Swap into Fleetwood



85silverSeville
02-05-09, 07:43 PM
Hello forum, I have a desire to swap out the tired 4.1L engine for a 6 cylinder Cummins turbo diesel. I know this engine weighs alot more ( est 1100lbs) and will require frame modifications like boxing, crossmembers, bracing etc. But I weighed the car with me in it ~ 170lbs + 3/4 tank of fuel and its 4300lbs. 2300lbs front, 2000lbs rear.

Now I figured I can remove the battery up front, and put two group 31 batteries in the trunk, this will take weight off the front end about 50lbs worth + original battery = roughly 100lbs off the front end by putting batteries out back. Now the hard part, even with moving batteries the front will gain 400lbs and the rear will gain 200lbs. I measured the firewall, wheelbase, COG of the cummins which is 15" front of the bellhousing.

Now Im estimating it will end up weighing just about 4800lbs+- and I googled the LImo versions, they weighed the same, except they are 2ft longer. Anyway my questions are how strong is the frame for this car 1985 Cadillac Fleetwood brougham 4 door, and how much Front axle weight does the limo support? What differences are there in the limo and sedan front suspension components? What would be a good upgrade in order to hold the weight?

Air bags would help level the ride, boxing the frame will make the backbone stronger, Maybe upgrade the lower control arms? Box them aswell?

Robin Banx
02-05-09, 08:07 PM
Don't forget the 800 lbs of insulation which you will need to keep your sanity while the engine is running. The injector rattle and related engine noise will drive you nuts. Worst swap in the world......... and that's not to even try to estimate what a swap like that will do the the resale value of your car. I have a 4.1 in an 83 FWB which is in good order at the moment but I am p[reparing for its eventual demise. I would suggest a GM crate motor of some sort would be a better bet for you.
Cheers........R.

jayoldschool
02-05-09, 08:23 PM
You are going to have a hard time getting that Cummins in there. I would highly suggest going with the earlier 5.7 diesel, or the later GMC 6.2/6.5. I have a friend who has put the 6.2 in his Roadmaster wagon, and would be able to tell you everything you need. Of course, the 5.7 would be very easy as it was a factory application. He also has lots of experience with the 5.7. He went with the 6.2 as it is a trailering application.

Let me know, and I can put you in touch...

96Fleetwood
02-05-09, 08:30 PM
I have a friend who has put the 6.2 in his Roadmaster wagon, and would be able to tell you everything you need. ...

Isn't he putting a 6.5 in a Fleetwood now?

jayoldschool
02-05-09, 10:17 PM
Not done yet, but that's the current project...

I'll get him to sign up here.

Aron9000
02-06-09, 01:25 AM
The 2003+ Cummins in the Dodge Ram applications are pretty quiet, for a diesel. I'd try to find one of those, the older ones are as loud as a semi-truck at idle.

You'll also need a stronger rear axle, I think the 4.1 V8 cars came with a dinky 7.5" 10 bolt.

Personally I would drop in a 6.0 Lq4 V8 with a 4l80e trans in there. Those were the gas motors in late model 3/4 ton GM trucks, vans, Suburbans, and a high output Lq9 version was found in the Escalade. SBC and BBC are great options if you want to keep it carbed, you can build those from mild to wild to 2000hp race motors.

CTSV_Rob
02-06-09, 02:00 AM
I think the Cummins in a Caddy would be cool. I love the motor in my 01 Dodge Ram 4x4.

Wondering why you don't consider a fresh LS motor for the swap? I hear you can buy them with the old school mounts and it would drop in. LS7 would be a sweet setup IMHO.

convert2diesel
02-06-09, 09:50 AM
Isn't he putting a 6.5 in a Fleetwood now?

Jay asked me to step in here so here goes. First some history. I have been doing diesel conversions on these cars now for about 20 years and I started using the 5.7 diesel that came with your car as standard (they had to get rid of their engine overstock somehow). If memory serves, you had to order the gasser as a no-charge option in 85.

It all depends on what you want the car for. If it will only be used as a daily driver and you don't want to win any races, then the 5.7 is very acceptable. If you need more horses for trailer towing or mountain climbing then the 6.2/6.5 is the next choice. If your intent is to suck the headlights out of the local HonToyissan crowd or you want to freak out the drag race community, then either the Cummins or a Duramax is needed. At which point, your car will turn into a money pit.

The 5.7 can be made to be reliable but it is no power house. You can either made good power or you can make it reliable. Not both! The benefits are the conversion is a direct bolt in with few, if any modifications. The engine gets remarkable fuel mileage (30 to 32 MPG (US) or 40 plus MPG (IMP).) at 70 MPH. Finding a good donor (start with an 81+ DX block, and add studded heads, copper ring head gaskets, Mahle pistons etc.) can be a challenge as most of these engines have been melted down to make newer Cadillacs by now. Even with turbos, recalibrated fuel pumps, and bigger injectors these engines are by no means a powerhouse. The best I have gotten without distributing the parts all over the road is about 165 HP.

The Roadmaster conversion has certainly paid for itself in spades. It is a 6.2 NA "J" code engine that gives me a consistant 160 HP and has done so now for close to 100,000 miles. By playing with the fuel pump, I can get very close to the same mileage as the 5.7 and can turn it up when I need to tow the trailer. My current problem is that we just bought a new trailer that is significantly bigger then our old one and the 6.2 just doesn't have the heart for the task. Ergo the Caddy project.

I would like nothing better then to shoehorn a Cummins into my car as the 5.9 is far and away the best automotive diesel available. I actually did alot of research on putting the Cummins into the Fleet and came up with the following conclusions:

1. The engine is just too tall for our engine bay. There is someone on the net that has one in a 70s Monte Carlo put if you look closely, he also did a 2.5 inch body lift and still he needed a power bulge in the hood.

2. Wieght is a factor but our chassis is more then strong enough for the added 400-500 lbs. The armoured car companies used these cars for years and added way more wieght. Any reputable spring company can size the coils front and rear to accomodate the Cummins.

3. Drive line design has to be the greatest concern. These engines start out with 400 ft/lbs of torgue for the original engines and up to 500 ft/lbs for the ISB engines. Other then an Allison or a Rockwell, there are very few trannies can handle that kind of twist with any reliability (remember I'm talking low speed torgue starting at 1,600 RPMs). If you want to stay with the automatic you can go either with a 4L80E (with standalone tranny controller) if you want an overdrive tranny, or the 400 if you need brick outhouse reliability. Nothing Chysler produces has ever been up to the task and even a Ford C6 would be hard pressed to handle the power.

The rear end would definitely have to changed out for something that could handle the torgue.

To sum up, if you just want a daily driver with acceptable performance and exceptional fuel mileage, then the cheapest diesel conversion has to be the 5.7. Just don't try for any 1/4 mile times. If what you want is a tire burning, backhoe hauling, stump puller then the Cummins or a Duramax (or for that matter any of the gassers suggested above) would be where to go. Just expect a great deal of time and resources will be needed plus your wallet will have a hole in it the size of all outdoors.

In my opinion, the 6.2/6.5 will give you the best bang for your buck and makes a good compromise. There is literally tons of stuff available for these engines and they have proven to be very reliable if you do all the mods.

Hope this helps.

Bill

91 Roadmaster Wagon, 6.2 diesel
91 Roadmaster Wagon, Bone Stock, Waiting for it's very own diesel
94 Fleetwood (thanks Fred)...newest diesel victim
84 Mercedes 300D...Still looking for the sixth cylinder
05 Pontiac Grand Am...feeling inadequate
97 Chev Suburban, 5.7 Vortec...Now for sale
Needed...bigger driveway

jayoldschool
02-06-09, 12:37 PM
Welcome aboard, Bill!

425 Dual Quad
02-06-09, 02:47 PM
Well well I never....
I thought this was a wind up joke at first. Now i see you're serious. Personally I would have thought a built '70 400 hp Cad 500 motor and posi would have been better.
Do you have pics?

convert2diesel
02-06-09, 04:04 PM
Welcome aboard, Bill!

Thanks for welcome. Actually joined last year when I started looking for the Fleetwood.


Well well I never....
I thought this was a wind up joke at first. Now i see you're serious. Personally I would have thought a built '70 400 hp Cad 500 motor and posi would have been better.
Do you have pics?

Nick:

In my line of work, I travel over 40,000 miles a year, mostly by car. Fuel economy is important. Thus the diesel conversions. I also tow our RV about 5,000 miles/year. My experience with the 500 Caddy engines has been that while very powerful, you couldn't blow enough fuel through a firehose fast enough to feed them.

Lets see if this works:

http://i156.photobucket.com/albums/t5/convert2diesel/Diesel%20Roadmaster/P1010428.jpg

http://i156.photobucket.com/albums/t5/convert2diesel/Diesel%20Roadmaster/P1010425.jpg

The whole write up and more pictures can be seen at:

http://www.impalassforum.com/vBulletin/showthread.php?t=139003&highlight=diesel+conversion

Bill

91 Roadmaster Wagon, 6.2 diesel
91 Roadmaster Wagon, Bone Stock, Waiting for it's very own diesel
94 Fleetwood (thanks Fred)...newest diesel victim
84 Mercedes 300D...Still looking for the sixth cylinder
05 Pontiac Grand Am...feeling inadequate
97 Chev Suburban, 5.7 Vortec...Now for sale
Needed...bigger driveway

96Fleetwood
02-06-09, 04:26 PM
Are you building the Fleetwood for towing as well?


Give me some time and you will see this in my Fleetwood:

http://www.gmhorsepower.com/ZZ502-Deluxe-Assembled.php


It already has been shoehorned in a '96 Impala SS... so why not a Fleetwood :lildevil:

Aron9000
02-06-09, 06:51 PM
^But that 502 is carbed, personally I think a Caddy deserves the better street manners of a fuel injected motor. You can make an easy 500hp with a LS2 or LS3 V8 with a very mild cam.

96Fleetwood
02-06-09, 07:15 PM
^But that 502 is carbed, personally I think a Caddy deserves the better street manners of a fuel injected motor. You can make an easy 500hp with a LS2 or LS3 V8 with a very mild cam.

Oh I am not doing it for the power. It will never be raced, it is too pristine for that. I am doing it for the "holy shit you have a big block" effect.... and because I can ;) Let them judge that at Vettefest!

85silverSeville
02-06-09, 10:01 PM
Hey I appreciate the responses and interest heres my take on things and the why. An Ls1 would make a great engine swap, nice fuel injected, an LS2 would be even better more displacement to move the heavy boat but it comes back the same problem, 89-91 octane. I would like to run veggie oil or biodiesel at will which a Diesel can do. I already know the power of the cummins Ive been working on Semi trucks for 10 years and love the power diesels offer. My family also owns a small farm and we have a Case 5250 with the legendary cummins 5.9 and that thing is an absolute joy to drive. Wheels cut and widened, filled up with water, 1500lbs front plates tractor weighs nearly 8 tons and pulls everything through anything at high speeds a 90HP John deere cant do. My father has an 04 Dodge Dually with 50hp injectors and that truck is too fast, it makes the 8400lbs curb weight seem light and limber, I just love the driving habits of a diesel. So much torque readily available half throttle is enough to accelerate with traffic, thats what I want, ease of driving I dont like WOT the 4.1 all the time really underpowered.

The reason I choose this particular car is the sheer size of it, long hood, strong chassis, RWD, Big body comfortable ride. Engine block is only 30" long and will fit easily from firewall to radiator but you are right it is fairly tall. I mearured that part and it comes very close to the hood. I would either have to flatten out the oil pan or set it low enough but not enough to hit the floor.

The Cr motors are nice, but I heard that they are heavier then the older versions by almost 100lbs so Im trying to save weight, too bad they dont make an aluminum head for it. Some plating or insulation can be put on the oil pan to keep the noise down, it really depends on what kind of engine I can find for it.

convert2diesel
02-06-09, 11:12 PM
The 5.7 diesel will give you equivalent performance of your V6 but will run on bio-diesel (up to B100). Straight veggie it will be a little wonky.

The Cummins is over kill unless you want to tow something with it. Unless you use the inline pump, don't expect to run anything other then #2 or B50. Veggie will stop it dead. Inline pumps (mid 90s ???) seem to do all right on B100 or veggie (though I don't recommend veggie for anything).

The NA 6.2 or 6.5 is more then sufficient to get up and dance on Saturday night or if you can find the room, stuff a turbo in it and really stretch it's legs.

One of my motivations is that I make my own bio-diesel when I have time and the 6.2 loves it. Know a number of guys running theirs on Veggie but IMHO it is only a matter of time before they will be writing paid on their engine. But thats another topic.

Good luck on your conversion. More then happy to help if needed.

Bill

91 Roadmaster Wagon, 6.2 diesel
91 Roadmaster Wagon, Bone Stock, Waiting for it's very own diesel
94 Fleetwood (thanks Fred)...newest diesel victim
84 Mercedes 300D...Still looking for the sixth cylinder
05 Pontiac Grand Am...feeling inadequate
97 Chev Suburban, 5.7 Vortec...Now for sale
Needed...bigger driveway

96Fleetwood
02-07-09, 03:25 PM
Does the conversion cost eventually pay for itself? What type of gas mileage are you getting with the diesel wagon?

All the LT1 Roadmaster wagons I have owned easily achieved 23-25 mpg on the highway.

convert2diesel
02-07-09, 06:16 PM
Are you building the Fleetwood for towing as well?


Give me some time and you will see this in my Fleetwood:

http://www.gmhorsepower.com/ZZ502-Deluxe-Assembled.php


It already has been shoehorned in a '96 Impala SS... so why not a Fleetwood :lildevil:


Does the conversion cost eventually pay for itself? What type of gas mileage are you getting with the diesel wagon?

All the LT1 Roadmaster wagons I have owned easily achieved 23-25 mpg on the highway.


In answer to your first question, yes. We bought a 28ft. Aerolite Cub (hybrid) last spring that wieghs in at about 5,000lbs with all the aerodynamic qualities of a grand piano with the lid open. The current Roadmaster can't handle it from a horsepower point so I am forced to step up my game by about 100HP. It will either be a Duramax or more probably a turbo or supercharged 6.5. Will see how the LT1 handles things and go from there.

When I first started doing these conversions back in the mid 80s, diesel was almost 1/2 the price of gasoline and the gas cars got horrible mileage, thus I could make it pay for itself in 20-25 thousand miles. With the lopsided pricing now on diesel vs gasoline, I will have to re-think the numbers. Bio-diesel is costing me about a buck a gallon (US) so that helps, but I can only run it at 100% for about 9 months of the year. In most areas, the difference between the cost of diesel and gasoline pretty well wipes out the mileage gains on a cost per mile basis. The only benifit is that road diesel pricing isn't as volitile as gasoline.

Currently my only real justification for doing it is "because I can" and the result allows me to run the car on a number of different fuels (diesel, bio, furnace, kerosine, jet fuel, scotch etc.).

Bill

I~LUV~Caddys8792
02-07-09, 06:27 PM
Whoa! A Cummins in a D-Body?! That's badass! For as much as I like the old 6.5L Turbo Diesel (TURBO POWER), I think the Cummins is a better engine. It's more powerful, probably more reliable, quieter, better on gas and just more badass. The only thing that's tough with the D-Bodies is that it's gonna be hard to fit that big long I-6 into the engine bay (or maybe not...?), plus the wiring might be a mess, and you're gonna have to custom fab the mounts and stuff.

Kudos to you though buddy! Keep it up!

96Fleetwood
02-07-09, 07:02 PM
Thanks for the reply! Please keep us posted on the Fleetwood, a Duramax would be sweet!

:cheers:

crunk04gtp
11-08-09, 03:49 AM
Sorry for resurrecting an ancient thread, (particularly because this is my first post), but I'm going to be putting together a similar project of a 1960s vintage and am interested to hear how this has been turning out.

85silverSeville
08-24-10, 04:22 AM
http://photobucket.com/FleetwoodCummins So I finished the swap early in the year, drove it for a month then had transmission problems( Auto:bigroll:), overall I like it. Even though I had no overdrive I got 4mpg better then the 4.1L, waiting on a few parts and I should have a Nv4500 in there in no time. Once I hit 5th gear 25 is a must, 30 possibility. Ride is soo smooth with the limo springs, boxed frame and boxed rear control arms, heavier 8.5" caprice axle but the transmission was a heat sink. Once I get it running with the 5spd a vgt turbo could put me into the 500 range, + nitrous = CTV smoked

YourMainParadox
08-24-10, 07:42 AM
I want to get 40 MPG in my hearse!

csbuckn
08-24-10, 10:24 AM
that is impressive. Nice work!

YourMainParadox
08-24-10, 04:16 PM
How much does it cost to get it done usually?

N0DIH
08-25-10, 12:12 PM
There is a guy on FullSizeChevy.com who put a Cummins 4BT in a 1/2t Chevy new body style (99-07) truck. Knocking down impressive mpg and power with it. That would be ideal in a GM RWD car platform. They still make crazy power for such a small engine, they can be found in the big box trucks like step vans and stuff.

Stingroo
08-25-10, 12:14 PM
I wouldn't call a Cummins small in any way other than the fact it's an L6. lol

They make 6 cylinder Cummins engines that go all the way to well over 19 liters.

N0DIH
08-25-10, 12:23 PM
The 4BT is the 4 cyl version of the 6BT. Look at the picts there of the 6BT, lop off 2 cyls, you have a 4BT... :)

http://www.4btswaps.com/forum/index.php

http://www.fullsizechevy.com/showthread.php?374390-4BT-Cummins-Turbo-Diesel-in-an-05-Silverado-%28with-pictures!%29


I wouldn't call a Cummins small in any way other than the fact it's an L6. lol

They make 6 cylinder Cummins engines that go all the way to well over 19 liters.

jayoldschool
08-25-10, 01:04 PM
The 4BT weighs in at 750 pounds! Ouch. The 6 cyl used in his swap is a staggering 930lbs!

Any shots of the car put back together? This looks pretty serious. Did you have any heat/vents/AC when you were done?

http://i616.photobucket.com/albums/tt250/FleetwoodCummins/IMG_1165.jpg

Stingroo
08-25-10, 01:16 PM
Wow almost half a ton? Holy crap, batman!

N0DIH
08-25-10, 02:33 PM
Not bad really, my 454 weighs in like a 4BT.... And the same 454 I have was in the Presidential Limo....

Aron9000
08-26-10, 01:18 AM
That's why I like aluminum block/head motors like the LS1. Fully dressed its about 400lbs, give or take 5-10 lbs.

N0DIH
08-26-10, 01:31 AM
And people wonder why I want to drop a LQ9 in my 99 K2500 Suburban.... iron block only adds 85 lbs or so....Not as much torque, but more fun....


That's why I like aluminum block/head motors like the LS1. Fully dressed its about 400lbs, give or take 5-10 lbs.

85silverSeville
09-26-10, 09:28 PM
Hey Forum, Im updating my Fleetwood with a Nv4500 and I need to mount up the clutch,... So the fuse box is in the way how should I go about moving it to a new location? Anyone ever put a clutch in a Fleetwood ? Pics and info would be great, thanks.

jayoldschool
09-26-10, 11:15 PM
I guess I shouldn't bother asking why you are putting a truck trans in a car...

Just unbolt the fuse box and zip tie it out of the way.

gtsviper2000
09-27-10, 10:37 AM
I guess I shouldn't bother asking why you are putting a truck trans in a car...


lol, they are supposed to be solid trannys though :)

jayoldschool
09-27-10, 12:58 PM
Yeah, if you need a hill climbing granny gear and two PTOs for your snow plow and salt spreader.

gtsviper2000
09-27-10, 01:12 PM
Yeah, if you need a hill climbing granny gear and two PTOs for your snow plow and salt spreader.

^^ im not ENTIRLY against that idea haha.

I hate chicago winters.

jayoldschool
09-27-10, 04:13 PM
I wonder if this guys is buddies with that other guy that was "installing" that Cummins diesel?

Stingroo
09-27-10, 06:52 PM
That other guy INSTALLED that Cummins, Jay.

jayoldschool
09-27-10, 08:15 PM
ok, Sting, if you call cutting half the car out to put in an engine then never finishing it. Hence, the "quotes" ;)

Stingroo
09-27-10, 08:18 PM
I thought I read in a reply that he got it to run successfully, and then it blew a head gasket.

Or something like that. I could be wrong. lol

85silverSeville
09-28-10, 03:03 AM
That was me, I did have the car running with the auto for about a month, blew the HG, fixed that then blew the transmission a week later. Cant stand auto it was a black hole all the power went in and all that came out was sluggish heat.

I removed the bulkhead connector and I might have to relocate it more towards the outside to make room for the clutch. Slight inconvenience but it should be worth it, I also obtained a free to me cadillac 86 fleetwood with interior damage thanks to a rott. Anyway I plan on yanking the A/c b/c it works, try to figure out how to get it back in with the engine in the way but Im sure I can make something work.

Anyone ever source a 9.5" limo axle? I might need one if the 8.5" breaks on me

csbuckn
09-28-10, 09:22 AM
What kind of HP and torque are you getting?

Stingroo
09-28-10, 04:11 PM
Ah! Well see there, Jay? :lol:


I wish you luck with your project. I think it'll be a cool car when it's all said and done. :)

jayoldschool
09-28-10, 04:42 PM
Well see there, Jay?

See post #29.