I thought I would write a tech article regarding a project that is currently in progress, for a change. I am in the middle of extensively channeling my 59 Ranch Wagon. I figure there are not too many vehicles with a larger floor pan than a 50s four door wagon, and the fact that I have cut out the entire floor pan, this article deserved a 401 classification. To date, I am only 50% complete with the channeling job. I will be posting my progress as I reach completion. So please join me in my channeling project as I take you through how I am going about putting the wagon on the ground. WooHoo- It's on the ground! Understanding Channeling: In short, channeling is the process of cutting out a portion of a vehicle body's floor pan, thus allowing the body to fit around the frame instead of sitting on the top of the frame. The primary reason to channel a vehicle is to achieve a lower stance without modifying the chassis and/or suspension. Although channeling sounds straightforward, it is not without its drawbacks and obstacles. As with any type of body/sheetmetal work, it is critically important to have a well conceived plan before making any type of permanent alterations. Planning Your Channeling Project: This is arguably the most important step. Depending on how much a body is to be channeled, there are many variables that can change significantly. The first order of business is to determine how much you want to lower your vehicle's body by channeling the floor pan. Once you have a target measurement, there are several hypothetical measurements and considerations to be made. Primary Channeling Considerations: Now that you have a target lowering measurement, the first thing to check for is interference between the body and the chassis. You will need to ensure that you have adequate clearance between wheels/tires and the front and rear fender wells. Secondly, you will need to check the door clearances for potential interference with the frame. Then you will need to make sure that you have adequate clearance for the tunnel to clear the transmission and drive shaft. Next, you will need to determine if there is enough additional height for the hood to clear the carburetor/air filter assembly. Once you have checked those three primary areas, you need to closely inspect the entire chassis, and make note of other potential areas of interference with the lowered body. Be sure to develop a solid solution to any noted issues before you cut the floor pan. Secondary Channeling Considerations: Once you have determined that there is adequate clearance between the chassis and body to accommodate channeling, there are several other variables you will need to take into account. Since at least a portion of the floor pan will be higher than stock, major consideration is interior head room, and ease of ingress and egress. Other things to take into account are pedal mounting heights, steering column angle and length, master brake cylinder height and potential interference with other engine components, exhaust interference, firewall clearance, and radiator clearance. The variables to take into account depends entirely on the specific vehicle to be channeled, the target height of the proposed channel, etc. As such, the above list should only be used as a general guide. Please be sure to closely inspect your vehicle for other potential problem areas before making any cuts. Preparing To Channel The Body: Now that the planning stage is out of the way, it is time to ready the vehicle's body for the channelingchanneling is that when the floor pan is initially cut, the body loses a great deal of its torsional rigidity. To combat this problem, it is necessary to internally reinforce the body. Reinforcing The Body: To keep the body torsionally stiff, it is necessary to weld in temporary structural supports and reinforcement. Before welding any supports, check one last time that the body is in its correct position, and that all the doors are aligned. The next thing to do is devise a series of supports for each of the A, B, C pillar areas, as well as the rear wheel wells. To keep the body torsionally rigid and "in square", weld the supports in an X configuration (See Figures 1-2). Depending on your specific vehicle, other areas may also need to be reinforced. It is good practice to over reinforce the body than not. Figures 1-2: (Click on thumbnails for larger image). Supports welded in an X configuration at the A, B, C pillars, as well as across the rear fender wells. All the supports are "hard tacked" to the bodybody in torsional alignment, I opted to use 5/8" rebar. Why rebar? Becuase it is extremely cost effective per linear foot ($0.50/ft), and when properly configured and welded, can be just as rigid as stock or tubing. It may not be slick or sexy, but there is no sense in cutting expensive tubing or stock for temporary supports. process. The first thing to do is install and align all the doors. If the doors are already in place, make sure that they open, close, lock, and otherwise function properly. An inherent problem with sheetmetal, and fully welded at the X intersections. Since the supports are not load bearing, and only need to keep the
Cutting And Channeling The Floor Pan: The first thing to do is clearly mark the sections of the floor pan you wish to remove. Place several supports under the floor pan, to keep the pan in place while cutting. Starting at one of the perimeter corners, use the cutter of your choice to begin cutting the pan (see Figure 3-4). Caution: Be very careful of fuel lines and the like, especially if you opt to use a plasma cutter or torch. Figure 3: Starting at the passenger front corner, I used a razor disc to start cutting the floor pan just to the interior side of the scuff panel. My entire floor pan was very badly rusted, so I opted to remove the entire pan. Please note that this extent of cutting is not necessary to channel the body. Figure 4: After cutting out the front 75% of the floor pan, and the entire rear cargo section of the floor pan, I was left with just the section of floor pan behind the rear seats. I left the stock mounting points at each end of the four body corners for support. I then proceeded to cut the remainder of the floor pan out. Once the entire floor pan had been removed, I then proceeded to cut down the four corner supports to the desired height. Adjusting The Channeled Body: Now that the floor pan has been cut, check the doors for proper alignment and functionality. If the cross bracing was properly executed, the doors should still be in alignment, and open and close smoothly (see Figure 5). Figure 5: With the entire floor pan gone, even the very large and heavy front doors are still perfectly aligned, and open and close flawlessly. Fine Tuning The Inherent Problems: With the cutting complete, it is time to lower the body into place and admire the new stance (see Figure 6-8). Figure 6-8: New and improved lower stance after channeling the body 3 Remember those considerations we talked about earlier? Now it is necessary to mock up certain items, and take some actual measurements. You will need to measure the interior headroom height, the channeled hood height, check for actual fender clearances, and determine radiator height. Carefully note any problem areas that do not match your expected changes. Hopefully with good planning, surprises should be minimal to non-existent. However, in the event that there are issues, now is the time to manipulate the body height to produce a working solution for the problem areas. Figure 9: Note the height discrepancy between the radiator mounting frame and front fenders. Thanks to thorough planning, this was expected. The modifications necessary to lower the radiator frame height will not interfere with the planned radiator size. Figure 10: Front fender clearance issues. The vehicle is currently sitting at its lowest point (parked height). Since the chassis is on air shocks, the ride height can be raised from 2-4. Nevertheless, some inner fender trimming will likely be necessary. This is a good example of why it is necessary to know your final wheel diameter and backspacing, as the wheel and tires currently on the chassis are rollers only. Figure 11: The new floor pan height. Here is a great example of the foremost problem to channeling. I am going to have to fabricate a completely new sub-frame to support the new floor pan, as well as figure out an attractive transition between the scuff plate and floor pan heights.
Part III: Proof Of Concept: Proof of concept pictures are always a bit embarrassing to show. Mock ups done with wood, cardboard, etc. are not very sexy. And then there are the comments of "you're not going to leave it like that, are you?" Regardless, mock up pictures are a really important means of showing how something goes from concept, to plan, to as built. So let's get on with the new floor pan sub-frame. Now that the floor pan has been cut out, it's time to mock up my design for the sub-frame. I had planned to use 1x3x0.125" rectangular tubing to build the sub-frame for the new floor pan.This particular size rectangular tubing made for the perfect choice. Not only does the tubing account for the new floor pan height, it fits very snugly along the inside of the scuff panels and the A, B, and C pillars. Also, the tubing will allow for the reuse of the stock body Figure 1: (Click thumbnails to view larger image). Here I used pieces of 2x4 dimensional lumber (actually 1.5"x3.5") for the initial mock up of the new floor pan sub-frame. The way I have the 2x4's configured, the 1/2" dimensional differences cancel out, giving a reasonably accurate representation of a 1x3 rectangular tube mock up. Figure 2: Overhead view of the the proposed sub-frame with a single horizontal crossmember in place. The 1x3x0.125" rectangular tubing will run on the inside of the scuff panels, all the way from the front firewall to the rear fender wells. Along the scuff panels and pillars, the body sheemetal is at least double, and in some places, triple thick. I will weld the entire perimeter of the tubing to the scuff panels, as well as the firewall, B pillar, and rear fender wells. These rails will form the basis of my sub-frame. The plan all along had been to create a sub-frame that allowed the new floor pan to be completely flat (see Figure 3-4). So far, the proof of concept proves that the floor pan can indeed be flat, and still accommodate the transmission and drive shaft tunnel with a period correct bench seat. A straight back, tuck and roll upholstered bench seat was a styling point I was not willing to give up, so I had to make sure the new floor pan, and more importantly- the new transmission and driveshaft tunnel, would accommodate the bench seat I wanted. I plan to do some junkyard shopping for a pair of 54" wide straight back bench seat frames. However, if I am unable to find suitable frames, my Plan B is to use bench frames from Glide Engineering or ISS Seating. Both manufacturers make 54" wide bench frames that will fit my new floor pan. Figure 3: Here is what the flat floor pan should look like atop the new sub-frame. Now you're probably saying "hey idiot, the drive shaft is on the inside of the crossmembers!" That is in fact true for the moment. What I plan to do is fabricate the horizontal crossmembers from side to side with the driveshaft temporarily on the inside. I will then mark out the absolute minimum tunnel needed to clear the drive shaft (which currently looks to be a ~ 2.5" radius), then cut the crossmembers and fabricate tunnel supports. Figure 4: Here is a better view of the proposed floor pan with the stock dash and brake pedal assembly in place. The clutch pedal will be going away since I have converted to a C6 automatic. The brake pedal will have to be cut down substantially to account for the new floor height. Otherwise, the brake pedal will work perfectly in its stock location. More than anything else, seating, interior head room, comfort, functionality, ergonomics, and style, and how all those variables would change as a result of channeling the body, were my primary concern. I certainly did not want to create a car that could not be enjoyed by friends and family. So from the very beginning, I was working with the relatively standard bench seat dimensions offered by major manufacturers (27.5" H x 23" L x 54" W [other widths available]). Now being a one project at a time person, I don't have any spare bench seats sitting around. Not to fear, I just used my better half's frilly outdoor seat cushions to approximate seating height and placement (see Figures 5-6). Most seats measure ~ 9+" under the back of the knee, and ~5+" under the buns. With those general measurements, you can make some general approximations and estimates. Figure 5: What is that, velvet?? *lol* Here I used outdoor seat cushions to approximate seat height and placement. These cushions made for about 7" of compressed padding when sat upon, which served as a good guideline. I am 6'1", and I have about 4" of interior headroom with this general setup. I am pleased with that, as it will allow most anyone to ride in the car without feeling cramped. Figure 6: Ergonomics are important to me, and in my opinion, are one of the details that really make a car. I was pleased to note that even with the floor pan channeled, my legs were not straight in front of me. I still have a nice 20+ degree break at the back of my knees, making the interior comfortable. Also, the dash and anticipated steering wheel location are still within comfortable distances. I have converted my C6 automatic to a full manual valve body, so I will have to build a suitable location for a floor shifter. mounting locations (see Figures 1-2).
Part IV: Sub-Frame Fabrication: With the initial layout complete, it is time to start the fabrication process. The first thing to do is cut the sub-frame rails and crossmembers from the 1x3x0.125" rectangular tubing. With the body on the chassis, I laid out all the tubing pieces in exactly where they should be in relation to the chassis, and "hard tacked" the tubing in place. I then lifted the body off the chassis and placed it on the ground, making sure that the body was flat and level. Next, I checked to make sure all the tubing had remained square and level. Once verified, I clamped the tubing to prevent any warping, and welded it in solid (see Figure 7). Figure 7: Rectangular tubing rails and crossmembers welded in. Note the weld on the B pillar. Welds were made on the A and C pillars, as well as along the underside of the scuff panels to firmly secure the new sub-frame to the body. Once all the sub-frame rails and crossmembers had been welded in, I installed the driveshaft and physically scribed where is crossed each of the crossmembers. In order to keep the crossmembers rigid, I need to fabricate tunnel supports. The tunnel supports will keep the structural integrity of the crossmembers, as well as serve as internal driveshaft safety loops and supports for the tunnel sheetmetal. The challenge of the tunnel supports is to keep the profile as low as possible, thus minimizing the finished tunnel height. Since the car is as low as it can possibly be at parked height, I can fabricate the tunnel supports with very close tolerances to the driveshaft, since the driveshaft will move away from the supports when the air shocks are inflated. Another challenge with the tunnel supports was ensuring that the crossmembers remained exactly square. To do this, I opted to pre-fabricate and weld the tunnel supports to the crossmembers before cutting away the center section for the driveshaft (see Figure 8-9). Figure 8: Tunnel supports welded in prior to cutting out the center crossmember section. This makes cutting the center section more difficult, but ensures the crossmember remains square. Note the tunnel support that surrounds the transmission tailhousing. This tunnel support also serves a second function as a tailhosing support. Figure 9: Completed tailhousing tunnel support, prior to grinding the welds flush. With all the tunnel supports welded in place, it is time to take the body off the chassis, cut the center section of the crossmembers, and test fit the driveshaft (see Figure 10-12) Figure 10: Tunnel supports in place with the crossmember center sections cut, capped, and ground flush. Figure 11: Trial fitment of the driveshaft. Note the close tolerances and centered placement of the driveshaft. This is where physically scribing the driveshaft location on the crossmembers proved to be key. Also, welding the tunnel supports in place prior to cutting the center section on the crossmembers ensured that things remained square and the measurements remained valid. Figure 12: Front tunnel support also serving as a transmission tailhousing support. Now that the front crossmembers and tunnel supports are finished, it is time to move on towards the rear of the vehicle. With the bodybody has been channeled 3", I should be able to reinstall this section of the floor pan (see Figure 13). Figure 13: Making use of the original floor pan. With a little bending, finessing, and additional trimming I should be able to weld this section of the original floorpan back in place. I should then be able to join this section with the new sheet metal floor pan for a nice, seamless fit. That's all for now. I'll try to wrap this article up just as soon as I can. Please stay tuned...
I dunno Zman...All the rest maybe...but this one he's gonna HAVE to cut and WELD!!! LoL What site is he getting all this from anyway????
Is this Tech Week? Did I miss Ryan's announcement? 15 how-to posts in a row, and all within a mere 32 minutes. Wow. Dude, pace yourself. Seriously. We have this thing called Tech Week every now and then and the best post wins a prize hand picked by Ryan. Incidentally, I saw in your profile that you write for OSR. Are these recycled from published pieces or ones not published? Not trying to be a smart ass, just curious if were getting a sneak preview. Vance
Wow, great post. Let me just throw something out here. You touched on having to shorten the brake pedal to clear the now raised floor. Isn't that going to reduce the lever ratio to the master cyl. to the point of creating a very hard brake pedal?
Thats a good point. Then again...when you can lay frame...do you NEED brakes? Seriously though...this is why a new guy shouldn't come on like gang busters and demand that you accept everything as gospel. I'm SURE the guy knows what he's doing, but sometimes its better to let people figure that out on their own...at their own pace.
That and putting something as non-specific as 'There' for where they live. That's a pet peeve of mine. Tell us where you live, there may be someone around the corner from you who needs your help and will never know you're close enought to save their ass. Sometimes I miss the old not so kinder and gentler HAMB. Vance
Great post. Very informative and answered a lot of questions. Looking forward to the next installment.
Nice post. Well written and nice photos to document. Im not bashing here at all, just trying to help you before you possibly get too far in the build so dont take this wrong.................. Just curious, but have you checked the suspension travel by jacking up the body, then when you jack it up to change a rear tire, will it tear out the floorboards and drive shaft tunnel with it being so close? Looks like every little pothole in the road will make the driveshaft scrape. Also, it looks like the aluminum tail shaft of the tranny is touching the crossmember you made. I think that might lead to a broken tailshaft or possibly a leaky seal from it getting banged around at best (they really do move around from the torque of the engine).
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