Cummins 4BT & Diesel Conversions Forums banner

1 - 7 of 7 Posts

·
Registered
Joined
·
13 Posts
Discussion Starter #1
I’m swapping a stock power, early 1st gen 6BT and an NV4500 into a 1998 Chevy K2500. I’ll be running the Cummins mechanical fan. The truck currently has a 350/4l80e with towing package. I don’t do any towing but I do live in Texas (very hot).

Is there a general rule of thumb for surface area or volume of radiator to keep the 6BT cool?
  • Run my GM 350 rad? (Core-only dimensions: 19”x34”x1”)
  • 88-98 GM 454 rad?
  • 88-98 GM 6.2/6.5 rad?
  • 1st gen Cummins rad?
  • 2nd gen Cummins rad?
  • Something else entirely?
 

·
Registered
Joined
·
1,569 Posts
Diesels don't put out as much heat as gassers, almost everyone has used the gasser radiator that came with the truck. You would be safe doing that, and see if it handles the heat load, one can always upgrade the radiator if necessary.

Ed in CO.
 

·
Registered
Joined
·
11,225 Posts
Ed, the 350 gas radiator will be too small to handle a 6bt. Would be plenty for a 4bt. Probably need to check the specs of the 454 and GM diesel radiators and probably choose the largest. Since they are the same brand they may fit with fewer mods.
 

·
Registered
Joined
·
51 Posts
I would attempt the factory radiator before planning on changing it, or changing it before trying it IMO.

I have a 1995 GM 3500HD. It had a 6.5 diesel and NV4500. I bought it from a shop that put a 12 valve 6bt in it. They utilized the factory radiator (i'll admit, it is likely a pretty big radiotor). But, for room constraints, they told me they used a Ranger fan on the pulley. It is very small, but it never overheats.

It is a great truck with exceptional factory four wheel disc brakes and nice 17.5"? heavy tires. The issues are it is only 2wd, (which is great until you need 4wd) and it doesn't have an intercooler.
 

·
Registered
Joined
·
8 Posts
Good question

My shop has done a lot of these conversions and my experience has shown is that if you are not going to tow, and your Cummins power is not turned up too much you will probably be fine to run your 350 radiator. If it is not sufficient then upgrade to the Big Block 454 radiator it will be the same size as your 350 radiator just thicker. Only a small amount of trimming to your core support at the corners of your core support, and drilling some new holes on your existing upper radiator mounts is required to get the perfect amount of clearance on the Dodge Gen 2 Fan and Hub. I go over some of these details on our youtube channel jonesysautoclub

Since, your truck was a gas burner to start with the GM 6.5L diesel radiator is not a good option as it does not have a radiator cap and uses a pressurized surge tank mounted on the passengers firewall. It fills through the lower radiator hose so you would have to source all of those parts. It is also the same size as the big block radiator with different lower water neck size.

I would stay away from the Gen 2 Dodge radiator and intercooler as it requires a lot of cutting and fab work to get everything to fit correctly especially if you are keeping your AC condenser. It is a nice setup if it is installed correctly it just takes a ton of work to do it right.

Also, since you are not going to be towing and not turning up the power. I wouldn't bother with a intercooler yet. Get your conversion on the road and broken in. You can always add that later if you need more power.

Lastly your handle looks familiar maybe we have sold you some parts already? If not we sell a lot of the parts to make your swap easier at our website: 1988-1999 Chevrolet GMC Truck Archives - Adventure Vehicles NW
 

·
Registered
Joined
·
13 Posts
Discussion Starter #6
Good question

My shop has done a lot of these conversions and my experience has shown is that if you are not going to tow, and your Cummins power is not turned up too much you will probably be fine to run your 350 radiator. If it is not sufficient then upgrade to the Big Block 454 radiator it will be the same size as your 350 radiator just thicker. Only a small amount of trimming to your core support at the corners of your core support, and drilling some new holes on your existing upper radiator mounts is required to get the perfect amount of clearance on the Dodge Gen 2 Fan and Hub. I go over some of these details on our youtube channel jonesysautoclub

Since, your truck was a gas burner to start with the GM 6.5L diesel radiator is not a good option as it does not have a radiator cap and uses a pressurized surge tank mounted on the passengers firewall. It fills through the lower radiator hose so you would have to source all of those parts. It is also the same size as the big block radiator with different lower water neck size.

I would stay away from the Gen 2 Dodge radiator and intercooler as it requires a lot of cutting and fab work to get everything to fit correctly especially if you are keeping your AC condenser. It is a nice setup if it is installed correctly it just takes a ton of work to do it right.

Also, since you are not going to be towing and not turning up the power. I wouldn't bother with a intercooler yet. Get your conversion on the road and broken in. You can always add that later if you need more power.

Lastly your handle looks familiar maybe we have sold you some parts already? If not we sell a lot of the parts to make your swap easier at our website: 1988-1999 Chevrolet GMC Truck Archives - Adventure Vehicles NW
Hi Joel,
Yes, I just installed your motor mounts yesterday actually. I had to trim a smidge from the passenger side mount to better clear the rubber tube on the turbo drain but other than that, they look and feel great.
That’s my plan exactly with the intercooler. Keep it simple and get it running in the truck and comeback to it later.
 
1 - 7 of 7 Posts
Top