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4bt Durango #2 (or more?)

58K views 100 replies 23 participants last post by  pigeon 
#1 ·
Hi,

I have jumped into a couple other threads that were related to what I was doing, but I guess its time to start a new thread for my project. I called it 4bt Durango #2 because of the other Durango project. For those who haven't seen my other posts, here are the details:

4bt from a Chevy bread truck, which I haven't seen (should be coming home Friday)
Dodge gas version NV4500 (so it will bolt up to my Durango t-case), and a Cummins input shaft.
Clutch is Napa Dodge Cummins, new replacement, including flywheel and all bolts
Hydraulic system will be Dakota pedal assembly, Dakota master cylinder, going to Ram slave cylinder.
Durango NP231HD t-case, which was behind the 5.9 motor.
Front suspension will be stock, so the oil pan will be heavily modified.

This will be my wife's daily driver, and our lighter duty tow rig (I have a '96 Ram Cummins for heavier loads) so it will be a study of economy and comfort,. meaning it must be as smooth and quiet as possible. She has driven my Ram enough to know what a diesel is like, but I'll do my best to make this a nice vehicle for her.

Now for my newest questions. For those who have installed the 4bt into later vehicles (such as the Grand Cherokee, Durango, and other late model vehicles), what is the best way to keep my gauges working properly? I'm assuming I'll have to keep the PCM to read the speed and transfer the signal to the gauge cluster, and the same goes for oil pressure, temp., etc., since the gauge cluster only receives a computer signal from the PCM, not individual signals from the sensors like older vehicles.

For the tach, I think one of the tach adapters from Dakota Digital might work. They are made for diesels, and I should be able to adapt the signal from their sensor to the Durango's tach somehow. If not, I could eliminate the Durango tach and install an aftermarket tach. Any thoughts?

I already have EGT and boost gauges, and will be getting a fuel pressure gauge before the project is finished.

I'll have more questions as the project begins this weekend, when I pull the motor from the van.

Jim
 
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#4 ·
Woohoo!!!!! My 4bt is home, and it runs GREAT! I ended up going down with my father's '06 Duracrap and his friend's 20 foot trailer. The Frito truck's front bumper was 6" or so over the front of the deck, and the back of the truck was close to 3' behind the back of the deck! It did tow great though, although that piece of crap Duramax only got 7 mpg on the way home!!! (trip down with an empty trailer was only around 12 mpg!) We got down there and the rain started (which is the reason I took the trailer instead of riding my bike down) so loading it was fun. It started right up and ran great, only a very slight puff of smoke when it first fired. After it warmed up I drove it onto the trailer (man, it barely fit between the fenders!) and we headed for home.

Because of the rain I haven't been able to find out much about it, except that the truck is in very good condition and all I was able to read off the tag is that its a 120hp version. Its still sitting on the trailer, but hopefully tomorrow will be drier and I'll be able to unload it, test drive it, and read the rest of the engine plate. Pics will be coming when its dry enough for the camera.

My initial thought of scrapping the truck is almost gone. I think because of the condition, I'll drop a good running 350 in it and sell it complete.

Jim
 
#6 ·
My initial thought of scrapping the truck is almost gone. I think because of the condition, I'll drop a good running 350 in it and sell it complete.

Jim
I've come to the same conclusion, too. It's always been hard for me to junk good stuff.
 
#8 ·
The truck pulled it great, but luck was on my side. The pickup is a quad cab '06 Chevy 3500 dually, so the wheelbase sure helped. The weather was also on my side. Although it was raining the whole way back, it wasn't windy. If the wind picked up, I'm sure it could have gotten scary quick. We were able to cruise at 65-70 with no issue.

More good news on the van. I had a few minutes to look it over tonight after dinner when the rain let up some, and found that the frame is in new condition- no rust like I'm used to up here. While looking under it, I noticed that it has been greased VERY recently- the little dabs of grease at all the fittings don't even have dust in it, so I'm fairly certain it hasn't been off the road long. My eyes picked up something else- the driveshaft U-joints are all new. Following the shaft up, I found that the transmission has NO dirt or grime on it...and a tag on the side of it (I wasn't able to get under and read it), and the aluminum looks new. I'm pretty sure this is a fresh transmission!

Good call on the thought of another diesel...I can get 6.2s a dime a dozen around here, so a couple hundred bucks should get me a good runner for resale. I really hate to chop up something this good, and even using it as a storage shed, although tempting, would be a waste of it. Oh well, the main thing is to get this engine out so I can start prepping it for the Durango.

Jim
 
#9 ·
O.K., I need some input to help me make a decision. For those who have worked on Dakotas/Durangos, you know about the front differential issue. The front diff assembly is bolted to the engine block, trans bellhousing, and engine mounts and is hung from the motor mounts with the engine. When the 4bt goes in, there is no simple way to bolt up the front diff. I have come up with a few possible methods of dealing with this.

-Make brackets to attach the 4bt to the existing Dodge motor mounts and diff, and hang it all just like the 360.

-Make brackets to attach the front diff to the 4bt and bellhousing and mount the entire assembly to the Durango frame with the bread truck motor mounts (I like this idea)

-Leave the diff hanging from the frame by the existing mounts, build a rear mount for the diff where it would have bolted to the bellhousing, then mount the 4bt independently of the diff assembly. This seems overcomplicated, and would require more room between the diff and engine to allow for movement, and I would have very little room as it is. I really don't like this idea, but threw it out anyway.

I guess the big question is, how would the front diff like the vibration of the 4bt, and would the additional weight of having the diff hanging from the engine cause the bread truck mounts to transfer more vibration? My theory is that having the extra weight of the diff bolted to the engine should reduce vibrations (if anything), so I think I should be safe.

By the way, this engine seems to be VERY smooth, quite quiet, and barely vibrates. Its almost as smooth at idle as the 360 in the Durango. I test drove the bread truck today for several miles and the engine seems very strong.

Jim
 
#10 ·
By the way, this engine seems to be VERY smooth, quite quiet, and barely vibrates. Its almost as smooth at idle as the 360 in the Durango. I test drove the bread truck today for several miles and the engine seems very strong.

Jim
There's something wrong with it for sure :dustin:

Certainly doesn't sound like the 4bt that I know.

I don't have any real answers for your front axle questions, i guess that's obvious since I ditched mine... How do you plan on clearing it? trimming the oil pan until it fits?
 
#14 ·
I am very intrested in the solution you find for the mounting brackets. My 89 Dakota will be getting the 4bt treatment in the near future. I am considering the dry sump route, but I have not picked up my cummins yet to start modifying.
 
#15 ·
Woohoo!!! The engine is out of the van. Kind of disappointing in one way, because now I can't start it and drive it. But its one small step closer to the Durango. Removal wasn't too bad, it came out the side door. Hopefully tonight I can drain the oil and start cleaning/degreasing it, and start on changing parts around. I have a Dodge intake plate with the grid heater, which will be replacing the aftercooler. I'm planning to use an intercooler once I get the engine in place and can get some measurements and plan exactly how it will be positioned.

Thanks Diesel Durango. I really didn't think the Dodge mounts would be a good idea, but I was hoping. I'll go with the original plan of using the bread truck mounts and attaching the diff to the block. I'm glad you have been through most of this before me (with the exception of the diff), so I have someone to bounce ideas off from. And its nice having someone who has made any mistakes before me, so it saves me from them :beer:

Jim
 
#16 ·
Here are the first pics of the engine. I removed the aftercooler and cut down the Dodge intake plate (shown). I also got the turbo, alternator, pulleys, and oil pan off. I test fit the flywheel, and ordered the Dodge adapters. I was going to use the adapter off my Ram, but for the cost of the adapters, I just bought one instead. The adapter plate was $75, and $50 more for the bellhousing and release arm. They should arrive early next week. While I wait I'm cleaning and prepping the engine. Hopefully all the parts will be here by next weekend and I can pull the 5.9 out of the Durango, yank the nose off, and test fit the 3.9.

I'm a little concerned about the A/C compressor placement. I was planning to use Dodge Cummins brackets, but they put the compressor too low, where it will hit the frame rail. Even my Ram has the frame dimpled to clear it, so it will never work in the Durango. I may be able to mount it high, maybe put the alternator a bit lower than the original 4bt bracket and put the compressor above it. I think I will still get decent belt engagement that way, especially considering how wide the belt is.

Jim
 

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#96 ·
I'm a little concerned about the A/C compressor placement. I was planning to use Dodge Cummins brackets, but they put the compressor too low, where it will hit the frame rail. Even my Ram has the frame dimpled to clear it, so it will never work in the Durango.

Jim
I, also, would like to use the Dodge Cummins brackets and accessories. Do you think notching the Durango frame could facilitate using the Dodge Cummins brackets? If yes, how deep of a notch would be necessary?
 
#17 ·
I have been doing some numbers crunching, and this is where I'm at: I have $3941.92 invested in this project as of right now, with most of the major parts bought. I still have minor stuff left. I also have an estimated $2300+ coming back when I sell off the extra parts and the step van. That will put the project around $1700. Hopefully I can finish it for between $2000 and $2500 when I'm done.

$2001 Motor (P30 van)
$630 NV4500 4x4 version
$465 Dodge Cummins clutch/flywheel, Napa Item#: NNCMU701191SK
$100 Pedal assembly, Dakota clutch master cylinder, Dakota clutch line, Dakota clutch slave cylinder
? Intercooler
? Dynamat or similar
? Intercooler tubing
$100 Dodge Cummins Input shaft & retainer
? Engine paint DE 1638 Cummins Beige
$122.50 Boost & Pyrometer gauges, Isspro (ebay)
? Fuel pressure gauge
? 3200 governor spring
$75 Dodge flywheel housing
$50 Dodge bellhousing
$15.49 Gauge pod
? Shifter boot
? Shift lever
$250.50 Dodge Cummins power steering pump, Dodge Cummins vacuum pump
$132.43 Dodge starter, grid heater assembly, grid heater relays

Parts sold/to sell:
$300 (as of today) Chevy adapter parts (on ebay, still climbing!)
$2000+ (estimated) P30 selling price, based on lowest prices I have seen them for around here with gas engines.
? Durango 46re transmission
? Durango 5.9 engine parts (injectors, throttle body, distributor, etc.)
 
#18 ·
where did you get the dakota pedal assembly? I can't find it as an option on car-part.com and i don't have all day to call salvage yards, most don't seem to respond to email.

Do you have ideas of where to put the intercooler? It is pretty cramped unless you move the radiator, or mount the intercooler behind the radiator. I have all the 6bt parts to put an intercooler in sitting here, but am not sure how to do it (or if it's worth it necessarily)
 
#19 ·
I have no plans yet for the intercooler. I'll play it by ear when I get the engine in place...which is happening this weekend. Please give me your opinion on this- I'm planning to keep the transfer case in the stock location, put the transmission crossmember wherever I have to for the NV4500, and let that decide the engine position. Hopefully that will work out. Then I'll see if I have room to move the radiator back a couple inches, and put the intercooler in front of it. I have looked at some of the intercooler sizes, and I'll choose which one I go with after I see how much room I have to work with.

For the pedals, I got lucky- I used car-parts.com and looked for any yards with a Dakota with manual transmission, and I found that our local one had a 5-speed for a '97 Dakota listed (3.9 I think), so i called about the pedals. I ended up with the pedals, master, and slave for $100. I'll probably put new master and slave in at some point, but these will be perfect for testing and to use for a while.

I just received the Dodge Cummins bellhousing and adapter today, and they look great. I can't wait for tomorrow night to get here, so I can start pulling apart the Durango.

Jim
 
#20 ·
That sounds like an interesting placement idea to me. I think it could work. I would try and bolt it all together, make sure you have enough cowl/firewall clearance. the closer you get, the higher the chances of down pipe interference. i have the GM drop manifold and i have like 3/4" between the down pipe and the firewall, that's with a stock P30 down pipe, custom wouldn't be a problem. The further forward you go, the more sump you will have to modify. Mine doesn't have much room to move in any direction and the back valve cover is right at the edge of the cowl, i had to bend the cowl so that they didn't touch.
 
#21 ·
I don't mind massaging a little sheetmetal, just nothing crazy. I see where you had to notch for your valve cover, thats no problem. I have to use a different downpipe anyway, the stock Chevy one is kind of rusty and has a split in it anyway. I'm going to order the flange and make up a pipe that sits as far forward as possible. With any luck I can keep my stock driveshafts, just to cut down on any custom parts. I'd like to be able to do this without ANY custom machining of parts (except the motor mount and diff bracket fabrication, of course).

For the diff, I have a new thought. I have spent a bunch of time looking at Dakota/Durango diffs, and now that I have my engine, I'm able to plan things better. I want to try making brackets to hang the diff assembly by the engine block using the mid-mount motor mount location. The bosses on the block look plenty beefy...hey, if they hold a 4bt in place (and the same design holds a bombed 6b in place), they won't have any problem supporting the diff. The passenger side is easy- just the one bracket to hold the end of the housing. The driver's side should work as well, and I should be able to make a long bracket that supports the bolt holes at the top of the diff housing, as well as a support that runs back for the pinion mount. Then I will mount the engine to the frame using the Frito mounts, and front mount location. The only hesitation I have is that any torque twist of the engine will also be moving the diff. If I have to, I can always add some kind of torque bracket later on.

I checked out my bellhousing and adapter tonight after work, and it looks like the Dakota slave cylinder will work with the diesel bellhousing. I may need a custom pushrod, but thats no problem. My schedule is to get the Durango stripped completely tomorrow night and Friday morning, then do the first test-fitting of the 4bt and NV4500 Friday afternoon/evening. Then I'll really be able to make some educated decisions about placement. That leaves Saturday and Sunday to work on the brackets. I'm hoping to at least have something tacked together by the end of the weekend so the engine can sit in the Durango during the week (and out of the way). Next weekend is for oil pan modifications. Then during the long Thanksgiving weekend, I hope to get it hooked up so I can test drive it. Of course, this is very wishful thinking, and I may still be fabricating come Thanksgiving. But I do work well with deadlines!

Jim
 
#22 ·
My wife and I got a good start on the project tonight. I got finished up with my work around 5:00, and she was already there with the Durango. By the time we ordered a late dinner, we had all of the fluids drained, driveshafts off, exhaust unhooked, and most of the underbody work done. When we left tonight, the whole nose was off. Tomorrow morning I just have to unhook a little more wiring from the engine, unbolt the motor mounts, and lift the engine, trans, and t-case out as a unit. Hopefully I'll be lowering the 4bt into place in the early afternoon. My wife is a big help, and along with taking a few pictures (which I was forgetting to do, because I was wrapped up in the work), she was the one who drained most of the fluids, removed the driver's side fender, and many other items. Its great having a wife who is willing to help out in the shop! :beer:

Pics will be posted tomorrow. We forgot the camera at the shop.

Jim
 
#23 ·
Well the camera is STILL at the shop, but I have lots to report. The motor mounts are made and tacked into place, and are holding up the engine nicely. The NV4500 is also setting in place bolted to the engine, and fits in the tunnel. Its a VERY tight fit, and I may end up massaging the sheetmetal slightly. The Durango 4x4 shift lever actually clears the transmission (just barely), although I don't have the actual crossmember and mount in place yet. I may have to trim an unused threaded mount off the side for more clearance.

The differential has just enough room to clear the block, and the oil pan won't need nearly as much modification as I thought. I don't have the diff bolted to the engine yet...in fact, its currently bolted to temporary brackets that I have tack welded to the frame to hold it in position. The final position of the engine isn't far off from Diesel Durango's position, with the front at almost the same exact height as what I could see in his pictures. I also positioned it side to side at almost the same position. I cut the cowl panel out and will be reconstructing it when the install is done.

Hopefully tomorrow we'll get the differential brackets fabbed up and tacked together. I may even start cutting the oil pan if we have time (doubtful). I did notice one thing while taking measurements. The shifter for the NV4500 is positioned a bit further forward than I would like, but I should be able to bend up a shifter to make it work without a problem. It will have quite an "S" bend, but I have seen worse, even from the factory. Hopefully I'll remember the camera tomorrow so I can post pics.

Jim
 
#24 ·
This weekend's work is done, and the Durango has been parked outside for the week. We didn't get much more done today other than working on the diff brackets and test fitting the transfer case, and cleaning up the shop. I did test fit the turbo and exhaust manifold, and found there should be just enough room for the downpipe, although I'll definitely need heat shielding for the firewall. My engine seems to be sitting back about an inch or so further than Diesel Durango's, because I wanted to keep my driveshafts stock. I test fitted the front shaft today and it fit perfectly! I posted all of the pictures of the weekend, and there are tons of them. I'm pretty tired and didn't get a chance to sort through them, but here they are:
http://s226.photobucket.com/albums/dd315/nhdiesel/Cummins Durango/

Jim
 
#25 ·

Turbo clearance. Not much room, but it should work.


Driver's side motor mount. I'll be adding gussets between the horizontal plate and the frame rail.


Passenger side mount. Not much room to work with. This is the area that forced the engine block and oil pan close to the diff. If I could have had another 1/2" of room to slide the engine to the passenger side, it sure would have helped!

More to come later.

Jim
 
#26 ·
I managed to get the transmission crossmember modified today to fit the NV4500 mount. I also cut the shifter hole in the transmission tunnel and installed the clutch and brake pedals. I was lucky that I didn't have to replace the whole bracket assembly, just pull the pin and install the new pedals on the old bracket. You would need the pin that comes with the clutch pedal, however, because its longer. I reformed the shift lever stub to fit the forward, under-dash location of the shift tower. Once I test fit the transmission, it looks like it should work fine. Here are a couple shots, more can be seen on my photobucket page.

Rear shot of the NV4500:


Dodge Ram mount on the modified Durango crossmember:


Shifter location:


Cummins Durango album

Jim
 
#28 ·
Thanks! Praise is especially nice coming from someone who has been through it before. Today I got the most complicated part of the project done- the differential brackets. Here are a few shots of the driver's side bracket. It mounts to the rear motor mount location on the block, and bolts to the cast in boss on the top of the differential and above the pinion. The angles were pretty complex to clear the starter, dipstick, and differential contour.







Jim
 
#29 ·
good lookin mount.

I started fitting my mn NV4500 yesterday, looks like it will have to come through the floor pretty much under the front of the dash. It looks like it will be pretty difficult to cut out the hole let alone getting a shifter to function. oh well, it is what it is :) I just can't wait to have a decent transmission in there.
 
#30 ·
Thanks. If you can get the shifter to work, I'm sure you will be very happy with the NV4500 swap. I was planning to swap one in even when I had the 5.9 in it, just to get rid of the crappy Dodge automatic.

I managed to get my oil pan 90% done today. I got it modified to clear the diff and passenger side axle extension, and checked the capacity. Before cutting into the pan I had filled it with water to the gasket sealing surface, and it took 16 quarts. Now it only holds 12. I only had to modify the pan below the normal high oil level mark, so I know the loss is accurate. I'm going to remove the bottom of the sump and use a leftover sump from a Dodge pan to extend it down. It will hang lower than I would like, but it will still be above the bottom of the diff. If this was an off road 4x4, I'd be concerned about how low it ends up, but for my wife's daily driver and our light tow rig, I'm not too worried about it. I can always fab up a skid plate for it in the future.

The pan is no work of art (unless you count modern art), but it actually doesn't look too bad. I couldn't find any 16 gauge sheet metal locally, and I was impatient to get on with it, so I used the Dodge pan to donate the steel. The nice part is that I had several pre-formed curves and angles. I'll have pics of that soon, I forgot to take some at the end of today.

Jim
 
#31 ·
cool, you are making some fast work.

I somewhat wish i had a newer nv4500, then you can get a short throw shifter, i think it might help with clearance issues for me. I wont' bed able to work on it until this weekend with thanksgiving and whatnot.
 
#32 ·
You might not be able to do a short throw shifter anyway. It sounds like you are limited for space by the shift tower (like me, but worse). A short throw shifter usually raises the pivot point of the shifter- therefore, raising the shift tower.

I heated and bent the shift stub shaft that goes into the tower (after pulling it all apart) for a better angle. It has a weird thread on it, 9/16" I think (or maybe 14mm metric) so most shifters won't fit on it. I happen to have an older S-10 shift lever that is a similar size thread (but different pitch) that I was able to lightly thread on, just to test the location, and it looks like the length is right. I was also surprised at the tight throw, by using the shorter shift lever compared to a Ram. Its really going to be a nice setup.

By the way, I don't remember if I mentioned it yet, but when you add the clutch lever, the clearance is VERY tight. Don't bother pulling out the whole bracket. There is a circlip on each end of the pivot shaft. Remove the clip from the left side of the shaft, and push the shaft through to the passenger side. That will let the brake pedal drop out. The shaft will drop out by the trans hump. Take the new (longer) shaft from a standard Dakota, and angle it up above the parking brake area, then slide it into the bracket. Do this without the bushing in place, because its VERY tight. Once you get the shaft slid in, put the bushing in place. Slide the shaft to the passenger side, into the bracket and the new brake pedal. Once the shaft is even with the bracket, put the clutch pedal in place, and slide the shaft back into the clutch pedal. Then put both clips on.

It sounds hard (and it is), but its much easier than pulling the whole bracket out.

Jim
 
#35 ·
Thanks for the tips, i think i have the shifter cutout mostly done, half of it is under the dash, ugh. it was a big pain to cut, but hopefully i won't have to make it much bigger. i will have to bend the shaft too, maybe cut/weld since i wouldn't have to take the whole trans apart to do that, we will see. there is an updated topcover with all i would need to convert on ebay, but it's 300 bucks... I think i will try with what i have for now. I was thinking of making it lever shift by mounting a bracket to the floor board forther back, what do you think of that idea?

Mine is an older style square shifter lever, so i don't know what will fit other than what came on it. yours is probably metric...of course.
 
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