From The Scratch-Built Hot Rod
Chapter 12: Mechanicals
By design, the individual sections presented in this chapter are not necessarily in chronological order. You may notice that in some of the pictures, we have jumped forward or backward in time. And in other pictures, certain parts of the construction will be completed even though they have not yet been described in the prior sections of the book. Hopefully this will all make some sense to the reader, and not be too distracting.
The pedals from the donor F-100 can be used for the project, but the mounting hardware must be fabricated from scratch. The parts and pieces used for the pedals are shown in Photo 12-1. From left to right are: the clutch pedal, the clutch pedal push rod, the brake pedal, two 1x2 rectangular tube support brackets (with mounting holes drilled for the support tubes), two support tubes cut from 1" pipe, and, above the support brackets, four plastic bushings from the donor.
To begin, a support tube is inserted into one of the 1x2 brackets, welded on each end and ground smooth (Photo 12-2). The second bracket and tube are welded together in the same way. The two brackets and the pedals are then assembled into one unit (Photo 12-3).
The pedal unit is positioned and welded to the firewall hoop at the front, and the windshield crossmember at the rear (Photo 12-4). Photos 12-5 and 12-6 provide a couple of views of the pedals hung in the car. Later in the construction process the pedals will be shortened a bit.
To support the clutch master cylinder and brake master cylinder when they are hung on the firewall, 1/4" flat stock (arrow) is cut and welded to the mounting brackets (Photo 12-7). The firewall sheet metal alone would not support the pressure put on the master cylinders by the pedal action.
Using a hole saw, the firewall and supports are drilled out and the master cylinders are bolted in place (Photo 12-8). Note that the clutch master, shown on the right in this picture, was later lowered approximately 2" so that the fluid reservoir would no longer extend above the firewall hoop. In addition, a new Wilwood master was swapped in for the stock unit shown in this picture. A new master brake cylinder was also used to replace this original.
Photo 12-9 shows how the push rods for each master cylinder are attached to tabs welded to the pedals.
Steering box mount
The project will use a 525 steering box. After mocking up the box and the tie rods to ensure there will be no clearance problems, the frame is marked for the location of the mounting bracket. The main faceplate and triangular gusset supports for the bracket are made using 3/16" flat stock. One-inch pipe, as shown in the photo, is used to provide the correct spacing to keep the bracket from interfering with the box (Photo 12-10). This portion of the mounting bracket is welded and ground smooth (Photo 12-11). The steering box is bolted to the bracket using the two lower mounting holes. An extension must then be fabricated so that the upper mounting hole on the steering box can be bolted to the bracket (Photo 12-12). The extension is made using a piece of 1x1 tubing, which is cut at a 45-degree angle at the top, and then rounded with a grinder to match the curve of the 1" tube spacer.
After tack welding the tube spacer to the extension, it is removed from the rest of the bracket to complete the welding and to grind the beads smooth (Photo 12-13). The extension is then mocked back up with the steering box, and welded to the main portion of the mounting bracket. Photo 12-14 shows the completed bracket after the welds have been ground smooth and painted with a coat of primer. The steering box can then be bolted to the mount (Photo 12-15).
The tie rods were cut to length from 1/4" wall, 1 1/16" tubing, which is then drilled and tapped at each end with left- and right-hand threads to accommodate 5/8" heim rod ends. With the wheels straight ahead, the tie rod from the steering box to the passenger side spindle is installed first. To complete the cross steering setup, a bracket is cut from 1/4" flat stock and drilled for a 5/8" bolt (Photo 12-16). This bracket is welded to the tie rod we just installed as shown at the arrow in Photo 12-17. The tie rod to the driver side wheel is attached to this bracket as shown in Photo 12-18.
Note that with this design, each of the tie rods is approximately the same length as each I-beam axle. By keeping both tie rods (Pitman-to-passenger and passenger-to-driver) approximately the same length as each of the I-beam axles, it reduces potential for bumpsteer, since the arc of travel for the tie rod will be virtually the same as the arc of travel for the axle.
Steering column and steering shaft
Mounting the steering column begins with determining where the column will pass through the firewall, and then cutting the required hole in the firewall sheet metal. Using a level and tape measure, the firewall is marked in direct line with the center of the input shaft on the steering box. Although this location does not have to be absolutely exact, we want the "forward shaft" (the intermediary shaft that runs between the steering box and the steering column) to be nearly parallel with the steering box input shaft, so that it will clear the engine mount and the exhaust headers. This mark gives us a reference point for the "left-right" location of our steering wheel shaft hole.
The mark also provides a reference point for the height of the hole we need to make in the firewall. It is the apex of the angle between the steering shaft and the "forward shaft". To determine the actual height and position of the hole, we just need to calculate the angle of the steering wheel shaft.
To calculate that angle, we remove the column so that only the steering wheel shaft and steering wheel remain. We then mock up the wheel and the shaft, placing the upper end of the shaft at the exact height it will be once the dashboard is created. To do that, a temporary "dash", in the form of a 2x4, is clamped in place and the steering wheel shaft is clamped to the lower edge of that temporary dash (Photo 12-19).
Using the reference mark we previously made on the firewall as our guide, we move the lower tip of the steering wheel shaft up or down against the inside (cockpit side) of the firewall sheet metal. We then "eyeball" the trajectory of the steering wheel shaft, and visualize an imaginary line intersecting with the line from the steering box to the firewall. The firewall is marked where the tip of the steering wheel shaft is then touching the inside surface of the firewall sheet metal. The steering wheel and shaft are then removed.
Since locating this hole in the firewall is far from an exact science, we first make just a 3/4" pilot hole through the sheet metal (Photo 12-20). This hole needs to be just large enough that our steering wheel shaft will fit through, but no larger.
The steering wheel and shaft are once again mocked up, but this time the shaft can be inserted through the small hole in the firewall, and the upper section of the shaft is once again clamped to our imaginary dash (Photo 12-21). We can now test if our hole location needs to be moved slightly left, right, up or down in order for the steering wheel shaft to intersect at an appropriate point with the "forward shaft" of the steering system. By drilling our initial hole to the absolute minimum size, we can compensate by up to an inch in any direction if we have made an error in our calculation of the hole's location.
Fortunately, our hole location is well-positioned, and we can simply enlarge it to accommodate the steering column itself (Photo 12-22). Note that as the hole is enlarged it needs to be made a bit oblong rather than circular, so that the column can fit within the hole at the proper angle. With the hole enlarged, the column is once again placed over the steering wheel shaft and the full assembly is mocked up in position (Photo 12-23).
To mount the column, we begin by cutting two mounting blocks, which will bolt to the stock mounting pad that is attached to the column (Photo 12-24).
The two blocks are bolted to the column mounting pad, and 1x1 square tubing is used to fabricate the balance of the column mounting bracket (Photo 12-25). The bracket is then welded to the pedal mounting supports (Photo 12-26 and 12-27).
As you may have noticed in an earlier fabrication photo, 12-23, the column is a few inches too long for this application. With the upper steering wheel end of the column bolted in place we have determined that 7 3/4" needs to be removed from the column.
Unfortunately, you can't simply cut 7 3/4" off the end of the column and be done with it. There is a critical bearing and race at the end of the column (arrow "A") which keeps the steering shaft centered in the column (Photo 12-28). To retain this bearing, the bottom of the column must be cut off, and then reattached to the column once the 7 3/4" section has been removed.
Note also in Photo 12-28 that there is a hole cut in the original column for the old gear shift levers (arrow "B"). This hole is not needed or wanted for this project, so the end piece is cut off just below this hole, and then the 7 3/4" section is removed from the column. These cuts are done with a chop saw, which provides for a fairly precise 90-degree angle on the cuts.
Photo 12-29 shows the three sections after cutting. The arrow indicates the 7 3/4" section which will be discarded. The other two sections are then clamped together for welding (Photo 12-30).
Photo 12-31 shows the shortened column after the welds have been ground smooth and a coat of primer applied. With this portion of the shortening completed, we can now shorten the steering wheel shaft. To do this, the shaft is assembled in the column, and the column is bolted to the mounting bracket. The steering U-joint is held in place and marked so that the shaft will extend fully into the collar at one end of the U-joint (Photo 12-32). Note also in this photo that there must be enough shaft length to accommodate the bearing retaining collar which can be seen just above the U-joint. Photo 12-33 shows the shaft with the cut off mark (arrow "A") and the bearing retaining collar (arrow "B").
Photo 12-34 shows the shaft, with the U-joint attached, after being cut to the proper length. Photo 12-35 shows the completed steering column mounting from inside the cockpit.
To finish out the steering system, a support must be provided for the "forward shaft". This support will also help stabilize the lower end of the steering wheel shaft and the U-joint. The forward shaft will ride in a heim-type collar, and that collar will be bolted to a bracket. The pieces for the bracket are shown in Photo 12-36. The "pedestal" on the left is made from 1x2 rectangular tubing and the arm (on right) is cut from 1 1/2" x 1/4" flat stock. The pedestal was cut and welded to form a triangular shape, for improved looks.
The two pieces of the mounting bracket are welded together (Photo 12-37), and the unit is positioned and welded to the frame. Photo 12-38 shows the completed bracket and heim-type shaft collar in place.
Clutch slave cylinder and bracket
The F-100 donor vehicle had a mechanical clutch linkage that was too bulky and too difficult to swap into this project. A hydraulic master and slave from a Mazda pickup truck were used to replace the mechanical linkage. Later, these Mazda components were swapped out for new Wilwood units.
The clutch master cylinder and pedal fabrication were shown previously in this chapter. A bracket must now be fabricated to mount the slave cylinder, so that it can operate the clutch.
The first step is to locate at least two existing bolts in the vicinity of the clutch throw-out arm, that can be used to anchor the bracket. Two bellhousing bolts (arrows) will serve the purpose well on this engine. With the bolt locations established, a posterboard pattern is made for a mounting plate.
The mounting plate should provide for solid attachment to the bellhousing, and it should vertically extend slightly below the bottom of the clutch arm. The width of the bracket should be measured so that with the slave cylinder on the outside edge of the bracket (farthest from the engine) the push rod will be centered in the dimple of the clutch arm. Using the paper pattern, a mounting plate is cut from 3/16" flat stock, drilled and bolted in place (Photo 12-39).
The second piece of the bracket, the faceplate, is another length of 3/16" x 3" flat stock on which we will mount the slave cylinder. This piece is purposely cut a bit longer than the mounting plate and is then drilled and cut to provide two "adjusting slots", which are positioned to match the bolt holes on the slave cylinder. These slots are cut after roughly eyeballing their position, so that when completed, the slave cylinder push rod will be centered in the clutch arm dimple (Photo 12-40). The slave is then bolted to the faceplate (Photo 12-41).
The faceplate and slave can then be positioned on the mounting plate, so that the slave's push rod fits perfectly into the dimple in the clutch arm. The top and bottom of the faceplate are marked so that the excess material can be trimmed off. The top and bottom marks also serve to correctly position the faceplate vertically on the mounting plate.
With both pieces removed from the engine, they are positioned and clamped together at right angles and welded. To provide additional strength, a top plate (arrow) is also cut and welded to the bracket (Photo 12-42). Although it can not be seen in the photo, a second but smaller triangular support piece is welded inside the bracket and just above the upper mounting slot. Photo 12-43 provides another view of the completed clutch slave mounting bracket.
It is not unusual when putting together a scratch-built car that you suddenly discover two key elements that both want to occupy the exact same space. No matter how well we plan, this is bound to happen. For this project, it happened when the Mustang radiator I had ordered was mocked up on the chassis. The lower hose connection on the radiator exited exactly in line with the front crossmember of the chassis. And to keep the radiator in the position we wanted, there was no way to bend a hose sharply enough to get around the obstacle.
The solution? Run the radiator connection right through the center of the crossmember.
To do this, the crossmember is marked and cut with a hole saw (Photo 12-44). A section of black pipe is then cut long enough so that there is enough length on either side of the crossmember to attach a radiator hose. On one end of the pipe, a "blow-off" lip is welded around the tip of the pipe and ground smooth (Photo 12-45). Do NOT, however, weld a lip around both ends of the pipe at this juncture, or you will not be able fit the pipe through the crossmember hole.
The pipe is slipped into the crossmember hole, centered and welded in place (Photo 12-46). At this point, the "blow-off" lip can be welded to the "clean" end of the pipe and ground smooth.
Before fabricating the radiator mounting brackets, the electric fan is positioned on the radiator and mounting brackets (arrows) are made from flat stock and drilled to fit the radiator and fan mounting holes (Photo 12-47).
The radiator (with the fan affixed) is then mocked up on the chassis, and mounting brackets are fabricated from flat stock. Note that the upright portions of the brackets (arrows) are bolted at the bottom and are removable, which helps when installing or removing the engine (Photo 12-48).
Photo 12-49 shows the radiator mounted on the brackets. It also provides a good view of how the "pass through" pipe (arrow) lines up with the lower hose outlet on the radiator. A straight section of hose can be used to create this connection. Photos 12-50 and 12-51 show the radiator mounting brackets from a couple of different angles.
Hot rods can tend to run a little on the warm side, so it is best to provide a shroud around the fan to assist in cooling. In most cases, the shroud should be built so that half of the fan blade depth is inside the shroud, and half outside the shroud. By using a framework of 1 1/2" x 1/8" flat stock, our shroud will be positioned almost perfectly. The framework pieces are measured to fit around the perimeter of the radiator core and small slots (arrows) are cut in the flat stock to fit around the fan mounting bracket (Photo 12-52).
Photo 12-53 shows the perimeter frame for the shroud placed on the radiator. The arrows indicate where the slots were cut to fit around the fan bracket. Also note that the shroud perimeter fits fairly tightly to the edge of the core, and allows exposure to virtually all of the core for the fan's circulation effect. Small tabs are welded to the perimeter framing (arrows) to attach the shroud to the radiator (Photo 12-54).
Using posterboard, (Photo 12-55) a pattern is made to cover the perimeter framework of the shroud. The radius of the fan is measured, and a circle drawn on the pattern and then cut out. Photo 12-56 shows the pattern being test-fit on the fan and shroud perimeter. The pattern is then transferred to sheet metal, and after testing to ensure the fan will turn freely, the resulting panel is tack welded to the shroud perimeter frame (Photo 57).
With the shroud removed from the radiator, it is welded up and ground smooth. It is then bolted back on the radiator for one final test-fit (Photo 12-58), and then given a coat of primer (Photo 12-59).
Heat and A/C
This project will be equipped with a Vintage Air clone "mini" heater and air conditioning unit, which also comes equipped with defrost. The parts and pieces for the kit are shown in Photo 12-60. The evaporator/heater box is positioned under the cowl, and mounting tabs (arrows) are cut and welded in place (Photo 12-61). The air conditioning hoses will be run through the floor board, but the heater hoses will be run through the firewall. This requires some sort of bulkhead connector. These connectors are availed as an aftermarket item, but they are often pricey. With just a few common hardware items (Photo 12-62) you can make your own. The only modification that needs to be made to these parts is to bore out the connector (arrow) to allow the 1/2" copper pipe shown above the connector to slip all the way through.
Photo 12-63 shows the bulkhead parts assembled, and how the copper tubing passes all the way through the connector. Two 7/8" holes are located and drilled through the firewall, (Photo 12-64) and the bulkhead connector is installed. The copper pipe is centered in the connector and soldered so that there is adequate tubing on both ends to allow attachment of the hoses. Also, it is important to note that a "blow-off ring" (arrow) has been soldered to the tip of the copper pipe on each end (Photo 12-65). This ring is made by slicing off a very thin strip from a 1/2" copper connector.
Cutting such a straight and thin slice of copper can be quite difficult with most traditional tools. To remedy the situation, a "mini chop saw" was utilized to make the cut (Photo 12-66). This very handy little tool is made by clamping an air-driven cutoff tool to a short length of board. The board is then hinged (arrows) to a wooden base (Photo 12-67). Note that various "guides" have been attached to the top of the base so that material can be held in place to make 90-degree and 45-degree cuts. Photo 12-68 shows the saw being used to cut the blow-off rings for our bulkhead connectors.
An aftermarket stainless steel heater hose kit is being used for the water lines to and from the heater (Photo 12-69). This kit comes with the chromed ferrule end as shown, but this application also needs a "dress up" or "beauty" ring to cover the nut on the bulkhead connector. The ring shown in the photo is a 5/8" long piece of 1 1/2" diameter aluminum pipe which has been sanded and polished. Photo 12-70 shows the two heater hoses attached to the bulkhead connectors.
To keep the hoses tidy and straight, a small bracket is made from clear plastic and 3/4" flat stock (Photo 12-71). Plastic is used in this situation to reduce wear or potential damage to the stainless hoses, which will undergo a good deal of flex and movement during road travel. The bracket (arrow "A") bolts to the engine mounting pad and is shown holding the heater hoses in photo 12-72. Note also in this photo that the A/C compressor (arrow "B") has been mounted below the alternator.
Photo 12-73 shows the condenser core mounted in front of the radiator and Photo 12-74 shows the heater box plumbed with its incoming and outgoing water lines.
Headlight mounts and adjusters
The Dietz-type headlights being used on this project have a mounting stanchion (arrow) and adjustment/tightening apparatus that are not really usable unless you are mounting on a large flat surface. To mount these lights on the top of thin pedestals, we'll need to toss much of the mechanism, and fabricate a new mounting and adjusting mechanism (Photo 12-75).
Looking more closely at Photo 12-75, you will see that the headlight housing has a small sphere at the bottom, which rests in a cup shape at the top of the stanchion (arrow). This allows the housing to be rotated up or down to adjust the angle of the headlight beam. A bolt (which can be seen exiting the bottom of the stanchion) runs down through the sphere and the cup and a nut, also shown in the photo, can then be tightened to hold the housing in position once it is aimed correctly.
Since the stanchion must be discarded, we need to fabricate a comparable "cup" for the headlight sphere to ride in. The cup is made by cutting off a short length of 1/8" wall 1" tubing. We then weld a 1" diameter washer on what will become the bottom of the cup (Photo 12-76). A tightening nut is then welded to the bottom of the washer (Photo 12-77).
To ensure the cup and tightening mechanism will work properly, it is tested on the stem bolt as shown in Photo 12-78. This test should allow full rotation of the headlight housing up or down when the nut is loosened, but should hold the housing in any position when the nut is tightened.
The headlight mounting posts are each made of two parts, a base pad and a pedestal (Photo 12-79). The base pad is cut from 1 1/2" x 1/4" flat stock, and is drilled so that the pedestal will slip into the center hole. Two mounting bolt holes are also drilled in the base. The pedestal is cut from 1/8" wall 1" tubing.
To attach the headlight housing to the pedestal, a nut is welded inside the top end of the pedestal tubing (Photo 12-80). Note the holes drilled around the perimeter of the tubing, which allow for welding the nut without making a mess of the threads. The pedestal can then be threaded onto the stem bolt of the headlight housing (Photo 12-81). Note that a nut (arrow) was first threaded on the stem. This nut will allow the headlight housing to be adjusted from left-to-right when the nut is loosened, but will hold the housing in a locked position when the nut is tightened against the top of the pedestal.
This adjustment and tightening mechanism is not the prettiest thing in the world, so it will be concealed with a slip cover made of 1" I.D., thin-wall tubing. This tubing slides up and down the pedestal to allow access to the aiming/tightening mechanism, and is held in place by a small set screw (arrow) on the back (Photo12-82). When finished and painted, the slip cover should be barely noticeable.
To complete the headlight mounting, the pedestal base is positioned at the front of the frame rail. A large center hole is drilled to allow the headlight wiring to be run hidden within the frame rails. Two mounting holes are then drilled and tapped so that the base can be bolted in place (Photo 12-83).
The pedestal is then inserted into the center hole in the base, and set vertical with a magnetic angle finder. The pedestal is tack welded and then removed from the car for final welding and smoothing of the beads (Photo 12-84). Photos 12-85 and 12-86 provide a couple of different views of the completed headlight mounts.
Front turn signals
Mr. Roadster turn signal lights are used on the front of the car. The lights are mounted on a small tab cut from flat stock, which is welded to the frame (Photo 12-87). A small hole is drilled below the mounting tab, and the wiring for the turn signals is inserted through the hole and then runs hidden within the frame rail along with the headlight wiring. Photo 12-88 shows both turn signal lights mounted on the car.
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