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Discussion Starter · #1 ·
Hello:
I have a 1994 C2500 Suburban and a 2000 GM Savanah Van 3500 - thinking about doing Cummins swap in each. Searching for thoughts as to whether I really want to go this direction. Suburban has a 6.5L with some sort of problem with pressure building in crankcase. The Van has a 5.7 350 in it. I will be totally new to the Cummins world if I do this. A friend with a concrete biz is totally into Cummins and has been trying to turn me. It seems to me the 6BT is the engine to go in either of these vehicles. Any reason to consider a 4BT in either?

Regarding C2500 Suburban:
I've been told by one of the diesel swap companies that I can't do the Suburban because it's a 2-wheel drive and a frame cross member will get in the way of the oil pan by about 2", whereas on 4x4 it doesn't get in the way. Anyone know if that frame member can be modified in some way to accommodate the 6BT? Is it possible to swap a frame member from a 4x4 to the C2500?

Regarding the Savanah Van 3500:
Can a 6BT fit? I don't know what tranny is in there currently, it's auto. I also don't really know what questions to ask about this. The van was given to me and I've never worked on one or owned one before. So it's a totally new experience.

Thanks for thoughts.
Cheers
Dave
 

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If your only hesitation with the Sub. Is the crossmember, they can be moved, I am lowering one on my ‘55 GBC now.

Ed in CO
 

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Hello:
I have a 1994 C2500 Suburban and a 2000 GM Savanah Van 3500 - thinking about doing Cummins swap in each. Searching for thoughts as to whether I really want to go this direction. Suburban has a 6.5L with some sort of problem with pressure building in crankcase. The Van has a 5.7 350 in it. I will be totally new to the Cummins world if I do this. A friend with a concrete biz is totally into Cummins and has been trying to turn me. It seems to me the 6BT is the engine to go in either of these vehicles. Any reason to consider a 4BT in either?

Regarding C2500 Suburban:
I've been told by one of the diesel swap companies that I can't do the Suburban because it's a 2-wheel drive and a frame cross member will get in the way of the oil pan by about 2", whereas on 4x4 it doesn't get in the way. Anyone know if that frame member can be modified in some way to accommodate the 6BT? Is it possible to swap a frame member from a 4x4 to the C2500?

Regarding the Savanah Van 3500:
Can a 6BT fit? I don't know what tranny is in there currently, it's auto. I also don't really know what questions to ask about this. The van was given to me and I've never worked on one or owned one before. So it's a totally new experience.

Thanks for thoughts.
Cheers
Dave
First, welcome to 4btswaps.

I don't know much about GM trucks, but, some random thoughts;

These are 3/4 ton and 1 ton vehicles. The 4 fits easier, but the 6bt is better suited to the vehicle size and weight - extra important if you live with altitude changes or are towing. NOTE: 4bt are getting very hard to find, 6bt is usually cheaper.

On the Savanah van, that diesel engine is going to be under your right elbow - Don't know if the dog house (engine cover) will fit without major modification. You could be building a 1 ton echo chamber ;).

On the Suburban. Search the build threads here for GM (Chevy & GMC) swaps. Confirm if:
1. The cross member location is a problem (Some "free" advice is not worth the asking price ;)).
2. How others mounted the engine. Ed mentioned moving the cross member. Another possible solution is using a body lift kit to raise the cab - thus creating clearance to raise the engine. Again, I don't know GM trucks.

Russ
 

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Discussion Starter · #4 ·
If your only hesitation with the Sub. Is the crossmember, they can be moved, I am lowering one on my ‘55 GBC now.

Ed in CO
Thank you Ed. Discussed what you said with a friend and we will look at it and see whether we slice and dice it where it is or move it. He's much more familiar with such things than me. Thanks again. Dave
 

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Discussion Starter · #5 ·
First, welcome to 4btswaps.

I don't know much about GM trucks, but, some random thoughts;

These are 3/4 ton and 1 ton vehicles. The 4 fits easier, but the 6bt is better suited to the vehicle size and weight - extra important if you live with altitude changes or are towing. NOTE: 4bt are getting very hard to find, 6bt is usually cheaper.

On the Savanah van, that diesel engine is going to be under your right elbow - Don't know if the dog house (engine cover) will fit without major modification. You could be building a 1 ton echo chamber ;).

On the Suburban. Search the build threads here for GM (Chevy & GMC) swaps. Confirm if:
1. The cross member location is a problem (Some "free" advice is not worth the asking price ;)).
2. How others mounted the engine. Ed mentioned moving the cross member. Another possible solution is using a body lift kit to raise the cab - thus creating clearance to raise the engine. Again, I don't know GM trucks.

Russ
Russ, thank you for the thoughts. The one about the echo chamber is a very good one and I did wonder about noise. I'm fairly certain they put the 6.5L diesel in the Savannah, but I'm going to look it up to verify. Even if they did, the noise is something to keep in mind for sure. Appreciate the thoughts as well regarding the body lift kit. I don't really think about such things, but a good idea to look into as well.
Thank you for taking the time.
Dave
 

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Discussion Starter · #6 ·
First, welcome to 4btswaps.

These are 3/4 ton and 1 ton vehicles. The 4 fits easier, but the 6bt is better suited to the vehicle size and weight - extra important if you live with altitude changes or are towing. NOTE: 4bt are getting very hard to find, 6bt is usually cheaper.
Russ
Regarding the issue of the 4bt vs 6bt. I've seen in the past both used with either class vehicle. At the time I only was thinking about the Suburban because I didn't have the 1 ton van. I don't push the Suburban hard. I don't do really heavy hauling. It came to me as a very inexpensive vehicle from a friend. It handles well the couple tons of granite, cement, stone chip, sand, etc... in my beefy little 4x8 trailer. So I do wonder if I would be fine with a 4bt. My friend who is Cummins guy has told me it's easier to get the 6bt these days. But he told me today that I will get 12-15mpg with a 6bt, with my GM 6.5L I get 18/19 highway; 16-ish mpg in lightweight city driving. This disturbs me a bit. I had hoped for similar mpg. So now I'm wondering if a 4bt could be fine and would it get me better fuel economy in the Burb.
 

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But he told me today that I will get 12-15mpg with a 6bt,
FWIW, I had a 1989 D250 with the 6BT 2wd and AT (non-OD). I would calculate MPG every few thousand miles...mixed light-duty driving. All my MPG numbers were between 19 and 21 MPG.

Roy
 

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I'd agree that the 6bt would be the better choice mainly because of availability. Depending on how much power you want you might use an Isb 170 which is a 3.9L 4 cylinder often used in delivery vans. Those normally came with an Allison 1000 transmission. The 170 was the HP on the engine and it had 440 lb ft of torque so it's not a total dog. No real power upgrades for that one since it is computer controlled. GM vehicles in general have issues of clearance with a Cummins. Member Rube Bonet aka Rob Bonney Fabrication, LLC may have a cure for the crossmember issue. He does parts for GM swaps. His email is [email protected] or phone 602-370-7955. Another company that specializes in GM swaps is Auto World. They are listed as Cummins Diesel Repowers and have been in business since 1989. Their net site is cumminsdieselrepowers.index.html The van may prove more of a challenge since space in the engine compartment tends to be tight. Cummins also builds an ISBe4.5 in Europe and now show availability in the USA. The 4.5 comes in power levels as high as 210 HP and 627 lb ft of torque. That would make a 6.5 look like a tinker toy. Buying one of those would probably lighten your pocket book a whole lot. Here's a listing on ebay for new ones for $14,695 plus freight. Cummins ISB - 4.5 - 210HP - NEW SURPLUS DIESEL ENGINE FOR SALE - 4.5L - ISB | eBay On top of that you'd need a special exhaust system for the smog control.
 
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