Frame swaps
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| − | *This subject comes up often, so I thought I would post this reply I wrote to a rodder who | + | *This subject comes up often, so I thought I would post this reply I wrote to a rodder who wanted to improve the ride, braking and handling characteristics of his 1949 International KB2 pickup truck. Many of the points I make here will apply to other frame swaps as well. |
*I like using OEM stuff whenever I can. The factory has well-paid engineers and mega-buck computing systems to figure everything out so that it will work well together and I like taking advantage of that, doing a frame swap and using all the parts that I can from a donor. | *I like using OEM stuff whenever I can. The factory has well-paid engineers and mega-buck computing systems to figure everything out so that it will work well together and I like taking advantage of that, doing a frame swap and using all the parts that I can from a donor. | ||
| − | After doing a little research, I've decided that I might use a Dakota donor truck for this project. The Gen I was made from '87 to '96. '91 to '96 used a 318 V8 as an option, so everything would be set up for the "A" motor of your choice, 273, 318, 340 or 360. I like the Gen I because of the fairly narrow track, 60.7" front and 59.5" rear. Everything got wider in the Gen II truck. Depending on the configuration of the Gen I Dakota, three different wheelbases were used, 112.0", 124.0" and 131.0. By the way, these trucks came with power rack and pinion steering. Another thing of interest is that these trucks came in 2WD and 4WD. So, if you wanted a 4WD International, you could certainly have it. Before removing any parts from the donor, roll it onto a scale and weigh just the front axle weight. Write it down. Now, weigh just the rear axle weight. Write it down. You will need this information later if you need to change springs. | + | After doing a little research, I've decided that I might use a Dakota donor truck for this project. The Gen I was made from '87 to '96.... '91 to '96 used a 318 V8 as an option, so everything would be set up for the "A" motor of your choice, 273, 318, 340 or 360. Of course, once you have your hands on a 360, a 408 stroker kit is only a phone call away. |
| + | http://www.speedomotive.com/ps-140-13-mopar-360cid-to-408cid-stroker-kit.aspx | ||
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| + | I like the Gen I because of the fairly narrow track, 60.7" front and 59.5" rear. Everything got wider in the Gen II truck. Depending on the configuration of the Gen I Dakota, three different wheelbases were used, 112.0", 124.0" and 131.0. By the way, these trucks came with power rack and pinion steering. Another thing of interest is that these trucks came in 2WD and 4WD. So, if you wanted a 4WD International, you could certainly have it. Before removing any parts from the donor, roll it onto a scale and weigh just the front axle weight. Write it down. Now, weigh just the rear axle weight. Write it down. You will need this information later if you need to change springs. | ||
If a guy were going to use the entire frame intact, he might get lucky and find that one of these three different wheelbases were exactly right for the International. If not, use the frame that is longer than the International and section it between the cab and differential, then have the driveshaft shortened or order a custom driveshaft. What I would do is to jack up the International on one side, remove the wheels and tires, then lower the body back to stock ride height and place jackstands under the frame. I'd roll the front and rear tires forward and backward in the wheelwells until I got the "eyeball" that I wanted and measure the wheelbase between the centers of the wheels. That's the figure I would use for the final wheelbase to build the truck on. Once I got the eyeball right, I might drop a line on a plumbbob from the center of the wheel to the ground and make a mark. Drop a line from some point on the body and make a mark. Measure between the points and write it down. Do this front and rear. Take the measurement off the BODY, not the fender or the bed. You'll need this info later. | If a guy were going to use the entire frame intact, he might get lucky and find that one of these three different wheelbases were exactly right for the International. If not, use the frame that is longer than the International and section it between the cab and differential, then have the driveshaft shortened or order a custom driveshaft. What I would do is to jack up the International on one side, remove the wheels and tires, then lower the body back to stock ride height and place jackstands under the frame. I'd roll the front and rear tires forward and backward in the wheelwells until I got the "eyeball" that I wanted and measure the wheelbase between the centers of the wheels. That's the figure I would use for the final wheelbase to build the truck on. Once I got the eyeball right, I might drop a line on a plumbbob from the center of the wheel to the ground and make a mark. Drop a line from some point on the body and make a mark. Measure between the points and write it down. Do this front and rear. Take the measurement off the BODY, not the fender or the bed. You'll need this info later. | ||
| − | The thing with using an OEM chassis is that everything is engineered to work together. What you don't want to do is decide after it's built, you want the front lower or the rear lower.... or both.... and have to dink with cheezy dropped spindles or cut the front coils and change the suspension geometry from "as designed". If you want to drop the truck "in the weeds", then use only the front and rear frame clips from the Dakota and retain the under-cab International frame section. Weld the three together at ride height and call it good. If I were going to use the entire Dakota frame in one piece (even if I sectioned it to get the wheelbase right), I would use whatever scrap pieces of material I needed to use to graft the Dakota frame rails to the frame rail holes in the International cab. This ain't rocket surgery. (yeah, I know that ain't the right way to say it, but I like it better). | + | The thing with using an OEM chassis is that everything is engineered to work together. What you don't want to do is decide after it's built, you want the front lower or the rear lower.... or both.... and have to dink with cheezy dropped spindles or cut the front coils and change the suspension geometry from "as designed" at the factory. If you want to drop the truck "in the weeds", then use only the front and rear frame clips from the Dakota and retain the under-cab International frame section. Weld the three together at ride height and call it good. If I were going to use the entire Dakota frame in one piece (even if I sectioned it to get the wheelbase right), I would use whatever scrap pieces of material I needed to use to graft the Dakota frame rails to the frame rail holes in the International cab. This ain't rocket surgery. (yeah, I know that ain't the right way to say it, but I like it better). |
| − | Here's how I | + | Here's how I might do the "in the weeds" build. |
| − | With your Dakota donor truck still complete and sitting level, put an inclinometer on the lower control arms and write down the angle. (assuming you're using a 2-wheel drive donor). This will insure that when the International is finished, the angle will be the same and all the suspension geometry will be stock. Use the inclinometer on some part of the frame or spring hat or upper control arm mounting points inside the engine compartment to find the fore-aft angle | + | With your Dakota donor truck still complete and sitting level, put an inclinometer on the lower control arms and write down the angle. (assuming you're using a 2-wheel drive donor). This will insure that when the International is finished, the angle of the Dakota lower control arms will be the same and all the suspension geometry will be stock. Use the inclinometer on some part of the frame or spring hat or upper control arm mounting points inside the engine compartment to find the fore-aft angle of the front of the frame. Write it down. With the Dakota front clip cut off at the firewall and sitting loose, disassemble and remove the springs and shocks. Re-assemble without springs using Allthread, washers, nuts and whatever it takes to put the Allthread in where the shocks mounted to hold the whole mess together without the springs and at the control arm angle you found when you put the inclinometer on the lower control arms of the Dakota when the truck was complete. Chock up the Dakota clip at the fore-aft attitude you found with the inclinometer in the engine compartment of the Dakota when it was still complete. With the International cab and center frame clip positioned at the height and attitude you want as a finished product, roll the Dakota clip into place and connect the Dakota clip to the International middle frame section. Use your gas axe to cut pieces off the Dakota/International frame clips where they interfere with each other as you roll the Dakota frame clip into position. Position the center of the front wheel of the Dakota clip relative to the International body using the dimension you wrote down when you originally dropped a line from the body. Of course, you'll want to fish-plate the connections you make at the Dakota/International frame connection to assure integrity of the graft. The resulting connection might look somewhat like a "Z" as viewed from the side. This is called Z-ing the frame. |
Same thing in the rear. Measure the top of the differential tube to the frame or frame member with the Dakota complete and sitting on level ground. Write it down. You will have to remove the springs and fabricate some contrivance to hold the differential in place at that measurement. I might use some U-bolts and scrap plate to bolt to the housing, then weld a couple of pieces of thick-wall tubing to the scrap plate, coming off the plate in a "V" to bolt or tack the other ends of the tubing to the frame of frame member. Just something to hold the differential in place relative to the frame at ride height while you position it to mate up with the rear stubs of the International frame. If I were using a 4WD donor, I'd use the same V-bar fixtures front and rear. Of course, you'll want to measure on an "X" pattern between the front and rear Dakota clips to insure that the clips are square with each other and also square with the International center frame section before you begin welding the whole mess together. You can do this easily by dropping a plumb line down to the ground or working surface from two identical points on the front clip and two identical points on the rear clip and measuring on an "X" between the 4 points. | Same thing in the rear. Measure the top of the differential tube to the frame or frame member with the Dakota complete and sitting on level ground. Write it down. You will have to remove the springs and fabricate some contrivance to hold the differential in place at that measurement. I might use some U-bolts and scrap plate to bolt to the housing, then weld a couple of pieces of thick-wall tubing to the scrap plate, coming off the plate in a "V" to bolt or tack the other ends of the tubing to the frame of frame member. Just something to hold the differential in place relative to the frame at ride height while you position it to mate up with the rear stubs of the International frame. If I were using a 4WD donor, I'd use the same V-bar fixtures front and rear. Of course, you'll want to measure on an "X" pattern between the front and rear Dakota clips to insure that the clips are square with each other and also square with the International center frame section before you begin welding the whole mess together. You can do this easily by dropping a plumb line down to the ground or working surface from two identical points on the front clip and two identical points on the rear clip and measuring on an "X" between the 4 points. | ||
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