detroit diesel or cummins 4bt?

[chemijeeper]

So right now I am deciding which route to go for my 89 GW diesel swap.
I have 2 viable options considering I am building this rig to be moderately economical and keeping my budget in mind.... I have option #1 that is a 93 stepvan, 4bt/t19. runs, drives the whole 9. 80K on the set-up. Comes with the wiring harness, linkage, p30 mounts, etc. The other would be a detroit diesel 3-53 mated to a AT545. This is just for the motor and the trans. I would have to fab up the mounts, linkage, wiring etc etc.I am finding out the specs and details of the detroit on monday. All I know is that it came out of an old gamma goat.

Now I know having a whole donor truck is key, but the price of the detroit would leave me with about $2k more to fill in all of the holes. I am going to be using a divorced np205 regardless of motor/trans choice so thats not being taken into consideration.

So basically I am asking for your guys opinions on what I should do. I know with the stepvan I could recycle the frame and aluminum body and make a good chunk of money back. I know about the cummins, but my experience/knowledge of the detroit is pretty limited(read REALLY limited).
Any one with experience with either of these motors? any input would be awesome. Thanks.

[Chevelleguy]

Why would you want to put a 159ci 3 cyl in your Wag? It is only rated at 109hp. I would go with the 4BT.

[chemijeeper]

Originally Posted by Chevelleguy

Why would you want to put a 159ci 3 cyl in your Wag? It is only rated at 109hp. I would go with the 4BT.

The 4bt is rated at 105-130 hp stock. Thats relatively the same range. Its all about the torque for me with the diesels.

[Chevelleguy]

I understand the torque aspect. But also, isn't the Detroit a 50 year old design, very heavy, and loud? I would think the 4BT would be much easier to find parts and accessories for. And from what I have read, the Gama Goats were not considered very reliable. How are the 3 cyl Detroits on vibration? The F3L Deutz deisels that we have in our rental fleet are know for somewhat high vibration, causing problems like breakage of throttle linkage and V-belt guards.

[Elliott]

What kinda mileage to you expect from the 4bt? Why not just step up to the 6bt?

[chemijeeper]

Originally Posted by Elliott

What kinda mileage to you expect from the 4bt? Why not just step up to the 6bt?

I am looking for around 24-27 area,(Hopefully). The main reason I am not stepping up to the 6bt is weight. I am already going to be packing on the pounds with axles, so I figured a 4bt would keep the weight out of the ridiculous area and allow me good fuel economy. I also just love the sound .

[The PIG Smith]

Originally Posted by chemijeeper

All I know is that it came out of an old gamma goat.

I've ridden in a Gama Goat while I was in the Army and they are extremely loud.
The driver is required to wear hearing protection!
There would not enough sound proofing material that you could install in the cab of a FSJ or large enough muffler build to quiet that thing.
Also, AFAIK, small 2 cycle Detroit Diesel have not been built for a while and so I am unsure of the parts availability for these things.
They do share a lot of parts with their larger 53 series cousins, like the 6V53.
Also, there is much more support for the Cummins 4BT.
Meaning, if you need help and want to ask a question, there are places to go to seek that help,
like www.4BTSwaps.com and http://cummins-conversion.com
I would not know what to go for help with a small DD.
Also, there are plenty of documented modification a person can do to increase the performance of a 4BT, but at the expense of fuel economy.
I know it have been hotly debated here about how much power a 4BT can make, but I personally believe a person can realistic make 200HP

Also, that Allison 545 is not something that I would brag about.
It is large heavy and does not have overdrive.
Fourth gear is 1:1.
It would be an okay tranny if you planning to do some very serious towing.
Check this out about the Allison 545:
http://www.ifsja.org/forums/vb/showthread.php?t=70102

[trellis8]

Go 4bt. The 545 trans is a monster, super heavy. My brother is building a 4bt offroad truck right now. You can easily get an adaptor to go to a Chevy bolt pattern turbo 400 trans if you want.

[COLOFIREMAN]

Originally Posted by Smith

I've ridden in a Gama Goat while I was in the Army and they are extremely loud.
The driver is required to wear hearing protection!

X2.

I say 4BT, the biggest reason I went for it was overall motor weight, tranny choices, and MPG. The 4BT and the 6BT are the same on the back and mostly on the front of both motors. I also love the fact that it's a proven swap that has been performed in countless vehicles across the US with lots of tech help on several sites.

Also something to think about between swaping in a 6BT and the 4BT. The 6BT weighs as much as a 4BT dry and your 360 together. All that weight on the front of your frame, plus a winch and bumper.

I don't know what the other motor weighs but I can bet it's more that the 4BT.

If you haven't yet, check out these sites www.4btswaps.com , http://messages.jeep2diesel.org/ , and my 4BT conversion in a GW http://www.ifsja.org/forums/vb/showt...t=1988+cummins

[chemijeeper]

Originally Posted by Chevelleguy

I understand the torque aspect. But also, isn't the Detroit a 50 year old design, very heavy, and loud? I would think the 4BT would be much easier to find parts and accessories for. And from what I have read, the Gama Goats were not considered very reliable. How are the 3 cyl Detroits on vibration? The F3L Deutz deisels that we have in our rental fleet are know for somewhat high vibration, causing problems like breakage of throttle linkage and V-belt guards.

I am not familiar with the detroits as far as vibration, but the 4bt is known for a decent amount of vibration. Whether the 3-53 vibrates more or less, I do not know.

And yes the 3-53 hasn't been produced since the 70's, but thats not necessarily a reason to write it off. Not saying I came into this discussion with an answer already in my head, I just like playing devil's advocate.

Hopefully someone will be able to chime in regarding the detroits reliability.

[chemijeeper]

The PIG Smith]I've ridden in a Gama Goat while I was in the Army and they are extremely loud.
The driver is required to wear hearing protection!
There would not enough sound proofing material that you could install in the cab of a FSJ or large enough muffler build to quiet that thing.

Is this louder than a 4bt? I know that these aren't quiet engines either! Kind of off topic, but how was riding in the gama goat? I would love to hear more about it. Looks like a pretty wild vehicle.

Also, AFAIK, small 2 cycle Detroit Diesel have not been built for a while and so I am unsure of the parts availability for these things.
They do share a lot of parts with their larger 53 series cousins, like the 6V53.

This is exactly why I started this post. I know there are rebuild kits out there, but the replacement parts sector falls flat on its face( from what I can find.)

Also, there is much more support for the Cummins 4BT.
Meaning, if you need help and want to ask a question, there are places to go to seek that help,
like www.4BTSwaps.com and http://cummins-conversion.com
I would not know what to go for help with a small DD.
Also, there are plenty of documented modification a person can do to increase the performance of a 4BT, but at the expense of fuel economy.
I know it have been hotly debated here about how much power a 4BT can make, but I personally believe a person can realistic make 200HP

I have followed 4btswaps.com religiously but the other site is a new one for me. Thanks! I have read about 4bts making upwards of 450-500hp, but the reliability of those rigs are in question(ie. drag set-ups)

Also, that Allison 545 is not something that I would brag about.
It is large heavy and does not have overdrive.
Fourth gear is 1:1.
It would be an okay tranny if you planning to do some very serious towing.
Check this out about the Allison 545:
http://www.ifsja.org/forums/vb/showthread.php?t=70102

Yeah I have no experience with the allison, and to be honest I just immediately thought good things because of the whole "Allison" stigma. But just for laughs, how heavy is heavy?

Thanks again for all of the great responses guys.

[chemijeeper]

Originally Posted by trellis8

Go 4bt. The 545 trans is a monster, super heavy. My brother is building a 4bt offroad truck right now. You can easily get an adaptor to go to a Chevy bolt pattern turbo 400 trans if you want.

Another chalk mark for the AT545 being an overweight behemoth. Got it. I wouldn't be running a Turbo 400 if I went with the 4bt, I would run the t19 that already is mated to it.

[chemijeeper]

Originally Posted by COLOFIREMAN

X2.

I say 4BT, the biggest reason I went for it was overall motor weight, tranny choices, and MPG. The 4BT and the 6BT are the same on the back and mostly on the front of both motors. I also love the fact that it's a proven swap that has been performed in countless vehicles across the US with lots of tech help on several sites.

Yeah I have read that the 4bt is just 2/3 of a 6bt. I have been leaning towards the 4bt after reading all of the responses, I just figured I could throw it out there and see what people alot smarter than me think.

Also something to think about between swaping in a 6BT and the 4BT. The 6BT weighs as much as a 4BT dry and your 360 together. All that weight on the front of your frame, plus a winch and bumper.

A guy in the UK swapped a 6bt into a fullsize Cherokee, but that was after much beefing up of the frame,axles etc. I never had any plans to use a 6bt because its such a heavy SOB. The 4bt is heavy as it is!

I don't know what the other motor weighs but I can bet it's more that the 4BT.

The 3-53 weighs in at 965#.

If you haven't yet, check out these sites www.4btswaps.com , http://messages.jeep2diesel.org/ , and my 4BT conversion in a GW http://www.ifsja.org/forums/vb/showt...t=1988+cummins

I have been following your build up threads over here as well as on 4btswaps.com, but thanks for the new site to look over! I am looking forward to seeing how you tackle the motor mount problem( so its easier for me!! )

[COLOFIREMAN]

I plan to use the factory mounts that came with the motor. The mount is made of 1/2 plate. I measured the frames and the van is 2.5 inches wider than the FSJ's frame. The mounts easily have that mush extra between the oil damper and place where it mounts to the frame. It's kinda like cutting a loaf of bread.

[Towtruck]

If you're considering a Detroit, why not a 4-53? Do a Google, there are some pickup swaps with that engine. Uses the same head as the common 8-53. Fairly compact as compared to the 71 series. Weighs in at 1100 lbs. There are adapters to get the Detroit SAE bell housing pattern to the GM. Outrageous exhaust note...

[chemijeeper]

I plan to use the factory mounts that came with the motor. The mount is made of 1/2 plate. I measured the frames and the van is 2.5 inches wider than the FSJ's frame. The mounts easily have that mush extra between the oil damper and place where it mounts to the frame. It's kinda like cutting a loaf of bread.

Thats awesome! I remember you explaining it to me through another post and I couldn't visualize it. Not trying to state the obvious, but tons of pictures please!

If you're considering a Detroit, why not a 4-53? Do a Google, there are some pickup swaps with that engine. Uses the same head as the common 8-53. Fairly compact as compared to the 71 series. Weighs in at 1100 lbs. There are adapters to get the Detroit SAE bell housing pattern to the GM. Outrageous exhaust note...

Thats an idea. The only reason I suggested the 3-53 is that I know where I can get one for relatively cheap money.

To be honest, all this talk has made me think that while a detroit would be cool and different, the 4bt is a seriously solid swap and the support for it blows away the detroit. But lets keep the banter going! I love hearing what you guys have to say on this.

[Towtruck]

If you want to keep the agricultural character of your FSJ any of these stone age engines (4bt or Detroit) should do the job. If you want to transform the driving experience, wait around for the new tech V6 diesels that will start showing up on the used market in the not too distant future...VW 3.0TDI, Mercedes 3.0, rumors of a GM V6. More money, but you get what you pay for. Also, I suspect it's easier and less expensive in the long run to get a wrecked Dodge pickup, shorten the frame and transfer the FSJ sheet metal than to go through the drive line swap exercise. If GM and Ford do come out with diesels in their entry level trucks I'll be looking for a short bed roll over...

[The PIG Smith]

Originally Posted by chemijeeper

Is this louder than a 4bt? I know that these aren't quiet engines either!

My brother has a Cummins 4BT in a 1997 Ford F-150.
It is much quieter than ANY Detroit Diesel.
Maybe about the same as a Cummins 6BT in a Dodge Ram.
You need to understand that a Cummins 4BT/6BT is a 4 cycle engine whereas the Detroit Diesel of this era is a 2 Cycle engine.
IMHO, 2 cycle engine will always be louder than a 4 cycle engine.
Think of your 2 cycle weed trimmer compared to the 4 cycle push lawn mower.

Originally Posted by chemijeeper

Kind of off topic, but how was riding in the gama goat? I would love to hear more about it. Looks like a pretty wild vehicle.

They are very loud and ride rough, but are a neat vehicle to ride in.
I would not wanna ride in one for long distance.
For me , it was the novelty of the Gama Goat that made it fun the few times I rode in one.
Here is a Web Site of dedicated Gama Goat enthusiasts
http://gamagoat.com/

Originally Posted by chemijeeper

I have followed 4btswaps.com religiously but the other site is a new one for me. Thanks! I have read about 4bts making upwards of 450-500hp, but the reliability of those rigs are in question(ie. drag set-ups)

Warning! You are gonna stir up trouble with this kinda of talk.
There are members here that do not believe that 500HP can ever be produced from a 4BT.
I do not know if they can or not.
I think most all agree that if a 4BT could produce 500HP, it would not be very streetable...this is where I will stop.
You need to continue to read and make up your own mind how wild a 4BT can be built.
I do believe most will agree a Cummins 4BT in stock or near stock form is very streetable and reliable.

Originally Posted by chemijeeper

Yeah I have no experience with the allison, and to be honest I just immediately thought good things because of the whole "Allison" stigma. But just for laughs, how heavy is heavy?

Dry weight of a Allison 545 is approx 300 pounds.
Here is another link to the Allison 545:
http://www.industrialautomatic.com/html/at542.htm

Just look how large this thing is:

I think a person would need to mod the firewall and tranny hump for this monster.
Just from the pic, you can tell it is larger than a TH400 or a 727TF.
Also, you may have issues with a transfercase with this thing, forcing you to use a divorced transfercase.

[Wayne]

I've seen some Studebaker trucks that came with detroit's
those things are really loud!

[chemijeeper]

They are very loud and ride rough, but are a neat vehicle to ride in.
I would not wanna ride in one for long distance.
For me , it was the novelty of the Gama Goat that made it fun the few times I rode in one.
Here is a Web Site of dedicated Gama Goat enthusiasts
http://gamagoat.com/

Thanks for the link. I had not heard of them until recently and they seem pretty funky.

Warning! You are gonna stir trouble with this kinda of talk.
There are members here that do not believe that 500HP can ever be produced from a 4BT.I do not know if they can or not.I think most all agree that if a 4BT could produce 500HP, it would not very streetable...this is where I will stop.You need to continue to read and make up your own mind how wild a 4BT can be built.I do believe most will agree a Cummins 4BT in stock or near form is very streetable and reliable.

Not trying to get anyone riled, just reiterating what I have read here:
http://www.4btswaps.com/forum/showthread.php?t=2692

here:http://www.4btswaps.com/forum/showthread.php?p=20839

and watched here:
http://www.hellmannperformance.com/10.63.wmv

Dry weight of a Allison 545 is approx 300 pounds.
Here is another link to the Allison 545:
http://www.industrialautomatic.com/html/at542.htm

Just look how large this thing is:

That is a bigun! That definitely chalks up a big "No!" for that portion of the idea. The conversion is already packing on the pounds, and a extra 150# for a tranny is a waste, especially when its no strong or more reliable than a lighter tranny.