Completing the car is now just one long series of small projects. Three are shown here.
The original chain tensioner design was not able to take up enough slack in the chain. The chain was either too short or too long, no matter how many links I used or where I put the adjustment. I had to come up with a new design with two idler sprockets instead of one, as you can see in this post. The bearings are special ceramic hybrids to handle the extreme chain speeds seen with a GSX-R1000 engine.
I’ve had a rear sprocket on the car for some time, but that was just for fitting. The lightening holes on that sprocket conflicted with the mounting holes required by the differential, so it wouldn’t have been strong enough. Instead, I ordered a blank sprocket from England and machined the correct mounting holes and center hole, then cut it in half on the bandsaw so that it could be mounted or changed without disassembling the whole rear axle and suspension.
I also built an adapter to go from the auto shift linkage to the transmission gear change lever. I bought a Suzuki GSX-R shift link rod from Ebay, cut off the front, and welded it to a threaded rod. The rod threads into a bushing I made that fits inside the eye of the shift linkage. The sleeve of the shift cable must be held securely, so you can see here the bracket that mounts it to the frame rails.
Chain tensioner sprocket floats on shaft
Starting the chain tensioner with a blank sheet of aluminum
First side outline finished, scribed onto second blank
Grind the two sided to match with the angle grinder
Drilling adjustment holes for idler sprocket shafts
Polish them up with a Scotchbrite pad on an adjustable-speed angle grinder
Chain tensioner in place, almost finished
Test-fitting new rear sprocket to old one as it can’t be mounted until cut in half.
Marking the rear sprocket for cutting, using the milling machine x feed
Milling the center hole in the rear sprocket on the milling machine rotary table
Cutting the rear sprocket in half on the bandsaw
Adapter for auto shifter cable to GSX-R1000 transmission shifter shaft
Adapter in place, connected to gear selector shaft
I was lucky enough to find some 7075-T651 aircraft aluminum plate, still with the Martin Marietta markings on it. Very useful for miscellaneous parts like this ECU mount. That stuff is strong! Almost as hard to bend as steel, but it makes for a very stiff end result. So I just cut this blank out of the aluminum plate, bent it in my hydraulic press, and added lightness using the milling machine. It mounts to the frame with aluminum clamshell mounts purchased on Ebay.
Yet another video update. Here you’ll get a tour around the car pointing out the newest additions, followed by fabricating the fuel swirl pot and mount, the first power-up of the electrical system, mounting components on the instrument panel, drilling the firewall for fuel lines, fabricating braided stainless steel fuel lines, building and installing the throttle pedal cable pull rod and the cable itself, building the ECU mounting platform, and machining the rear sprocket to fit the differential.
The car will use standard Honda Civic axle halfshafts, and I had the choice of cutting, sleeving and re-welding them, or building extenders that effectively widen the differential to meet the unmodified halfshafts. The cut/sleeve/re-weld option would eliminate the axle hardening and leave unknown strength, and I’ve since seen an example where this was done and the axle broke right at the weld. The option of “widening” the differential has several advantages. First, we can easily replace the halfshafts if necessary in the future with off-the-shelf parts. Second, moving the inner constant-velocity joint closer to the plane of the control-arm pickup points minimizes the plunge, or change in length, required as the suspension moves through its travel. Third, the halfshafts become equal length, eliminating torque steer. Now you may say “but, the extensions will be of different length and will twist unevenly so the torque steer won’t be eliminated”. The extensions will be much stiffer than the axle shafts so that won’t be the case.
So the choice was clear. We started with a differential and a couple of halfshafts as raw material…
I need to be able to lift the engine into the chassis, but due to the lowered floor of the work area a standard engine lift won’t work. While I’m at it, it would be nice to be able to lift the entire assembled car off the build table, turn it ninety degrees, move it to the door, and roll it out of the shop. Below is the solution. Sorry there aren’t any plans. The build process was “go to your local metal recycling center, buy some scrap beams, clean them up, cut them as necessary, and weld them together”. I’m getting more comfortable with winging it in the machine shop.
Also shown below is a mount I built to mount an angle grinder on the lathe. Parting-off has always been a problem. I’m just about to make the engine mounts, requiring at least 36 cutoff operations, and I figured I’d better solve the problem. I have a cutoff tool but only purchased a small number of carbide inserts; the inserts wear out really fast and I either have to order more from the US or drive at least an hour to a store that MIGHT have them. This baby works great, giving a clean straight cut. Just have to be careful not to let the abrasive get into the lathe.
Here’s what the overhead beam looked like when I started.
Drilling holes to mount the wheels. Milling machine makes this easy.
Welding the uprights to the wheel supports
Thick steel is so much easier to weld.
Welding the uprights to the overhead beam, upside down. C-channel is temporary, so it doesn’t fall over.
Finished. Trolley and chain hoist bought at Hardware House, Rayong.
So easy, even our spokesmodel can do it.
Test lifting the chassis. Easy!
Building adapter to lift the engine.
First lift of the engine.
While we’re building tools, here’s a holder to mount the angle grinder on the lathe.
Parting off has always been a problem. Not anymore. Plastic is to keep abrasive off lathe.
Next up: mount the steering column in the chassis. Nothing magical here, just lots of little steps. The steel bearing cup insert did work well at preventing distortion during welding. To get a proper press fit for the rear support bearing I decided to use my new internal bore gauge. At first it didn’t work at all (made in China, of course), so I had to disassemble it completely, figure out how it was supposed to work, unstick the rusted shaft, replace the dead battery, and reassemble it. All in a day’s work out here on the frontier. So now I can measure both holes and shafts to a few microns and press fits are much easier to make.
Front bushing; sheet metal cut on bandsaw and with die grinder
Front bushing support bent to shape
Front bushing support cap, ready to weld
Finished front bushing support
Turning steering column rear bearing cup
Finished rear bearing cup
Finished rear column support parts
Steel insert bushing to prevent distortion of the bearing cup during welding
Rear support, ready for welding. Note steel insert to prevent distortion.
I originally sent all these parts out to the CNC shop, but they never got back to me with a quote so I ended up making everything myself. The spline onto the steering rack was a tight press fit, so for now the entire column including the rack is a single assembly. I don’t know it’s possible to remove the rack later, and I’m not going to try as it might destroy the rack. The U-joints are special units from Sweet Manufacturing in the US, but don’t seem to be anything special. In the future I might try to adapt standard Honda steering column U-joints and column splines. These use a perpendicular pinch bolt so the column can be disassembled at each joint.
Parts turned on lathe, purchased, and laser cut
Front bushing and adapter
Finite Element Analysis (FEA) mesh of collapsible steering column joint in frontal impact
Finite Element Analysis (FEA) of collapsible steering column joint under maximum torque
Finite Element Analysis (FEA) of collapsible steering column joint in frontal impact
Collapsible column takes shape. 1mm steel is strong in torsion, weak out of plane.
Collapsible section finished
Finite Element Analysis (FEA) mesh of steering column quick-release adapter to column.
Finite Element Analysis (FEA) of steering column quick-release adapter to column.
Turning the adapter from column to quick-release
Finished adapter from column to steering wheel quick-release
Parts finished, still need welding
Welded double U-joint. Note clocking of joints. Important!
Welding the U-joints. Kept cool with wet cloths.
Machining the steering wheel to fit the quick-release.