Back to chassis....

In one of the previous posts we completed building out the tubing structure that will become the main floor section of the chassis.

In this post, we started by mocking up this completed tubing structure into the body, clamping it in multiple locations to ensure that it was aligned and leveled in the proper location using the rear S2000 subframe mounts as reference, which we also located into the new crossmember to serve as subframe mounting pads.

Applied a few short tack welds in each corner to ensure nothing moved, and then proceeded to stitch weld the new floor section to the inner rocker panels that we fabricated and installed earlier into the body structure.

 

Next, we re-installed the transmission, and set it to proper height with temporary piece of plate steel at the rear in order to check the clearance down the floor section where the transmission tunnel will be located.

 

 

Encountered some minor interference from an extraneous tab on transmission, which we proceeded to grind off. We will eventually need to take a small scallop out of the frame tube in the same location for additional clearance, but overall, the transmission fits very well. 

 

 

Dummied up a short piece of exhaust tubing of appropriate diameter to simulate the driveshaft location....looking good for clearance over the floor section.

In the next post we'll be working on connecting the new floor section to both the front and rear rails we fabricated earlier.

Tools...everyone loves Tools !!

The weather this year has been crazy, seems like the snow and winter will never end !

So rather than bring the Mini back inside the shop to continue on the chassis work, decided to start work on building the tube bender that will eventually be needed to construct the majority of roll cage and upper chassis assemblies.

I had some previous experience building a 6 point roll bar setup for my Camaro build a few years back, (https://www.flickr.com/photos/spetroff/sets/72157632420243515/) but farmed out all of the bending for that project. Given the shear number of tubes and bends that will be needed on this Mini build, decided that constructing the roll cage in house this time was the better way to go.

Did some research a while back on what tube benders are available in the marketplace at a reasonable price point. Looked at the JD Squared, Pro Tools, etc. and discovered a number of people were having great success building their own benders using a set of plans from Got Trikes. Liked the fact that it utilized simple construction techniques, readily available materials, and used the Pro Tools Model 105 tube dies. Also, the design allowed for the addition of air/hydraulic assist ram to reduce the muscle power required as with other standard tube benders.

http://www.gottrikes.com/Tube_Bender.htm

Given the majority of the roll cage tubing we will be using is 1.5" DOM, I also picked up a new Pro Tools 1.5"OD x 4.5"CLR x 240 Degree Die Set from a local off-road vehicle parts manufacturer, TMR Customs. They were very helpful, and were familiar with the bender design that I chose and had good things to say about it. Great bunch of guys.

http://www.tmrcustoms.com/store/

While researching the benders, I also discovered that a number of people had praised the use of tube bending design software from a company called Bend-Tech. Given the fact that the layout of all the roll cage tubing required will be all custom designed, figured that this software would pay for itself in time savings and wasted dollars in expensive tube bending mistakes. Ended up purchasing the Bend-Tech EZ 3D and played around with it for an hour or so, and I must say it's super easy to use and comes with a large number of built in pre-defined templates that you simply plug your own measurements into.

http://www.bend-tech.com/

Picked up some plate and square tube steel, some hardened shaft and got started. Made some progress with building out a few of the sub assemblies of the bender. More to come.....

Chassis continued.....

Got busy welding up the tubing, using the fixture we created in the previous post to keep all of the tubes located correctly. Started by going around the outside perimeter with series of tack welds in order to help minimize distortion, then allowing it to cool, and then worked on tacking the inner tubes.

After tacking up two complete sub assemblies (left and right), mocked them up against the rear cross-member and proceeded to weld the entire assembly together.

 

 

 

Tacked a short piece of tubing temporarily across the front to maintain square while going back over the entire assembly with finish welds.

 

 

 

 Once the welds cooled down, took some of the higher weld beads down with the grinder and then proceeded to use a flap disk to finish up the joints.

 

 

More chassis fabrication

Took the plans that my brother drafted up in AutoCAD, and printed out via plotter in 1:1 scale, and taped them down to a sheet of 3/4" plywood. The design was laid out so that each side of the floor was the same, allowing space for the centre transmission tunnel, which allowed the same fixture to be used for both sides, essentially flipping one of the completed sections over and linking them together with additional substructure for centre tunnel. 

 

Proceeded to rip some additional 3/4" plywood into 3" strips that were then screwed around the inside and outside perimeter of the drawing points where tubes will be laid.

Using the measurements from the drawing, fired up the bandsaw and got started cutting tubing, and laid them out in the fixture one by one, making sure the joints are tight with optimal gaps for welding.

Once the first complete set of tubes were constructed, started with the second set for the opposite side.

Two complete sets of tubes, ready to be welded up.

More chassis work....

Moved up front to start work on laying out the tubes to connect the front subframe.

First item on the agenda is to build out a fixture or jig that uses the front frame sections from the Honda S2000 I obtained previously as reference points. This fixture will then be used to locate the upper control arm and strut mounting points which will then be transferred onto the new tubing members when we get to that point.

Next, laid out the mounting points for the S2000 front subframe onto the new tubing rails, milled out the holes, and then tack welded the threaded bosses in for the mount bolts.

Also spent some time figuring out the mid section of the chassis layout. Captured the dimensions required and had my brother draft the layout in AutoCAD.  He was able to print out the rendering to full size using his plotter which will be great when it comes to laying out the tubing. Will share this with the next post......

Slight diversion

Only had single day off over holidays to work on car, so decided to take a slight diversion away from the chassis focus and devoted some time to the interior. Given the limited amount of interior space inside a Mini, picked up a Kirkey aluminum race seat (will be adding a second for passenger side) that should work quite nicely given the narrow seat width.

The seats are quite comfortable to sit in, but would prefer to have some creature comforts for longer street drives, so the plan is to add some additional foam inserts for the lower and upper seat backs and then have them upholstered in some distressed black leather that I picked up.

Decided the seat foam will need to have some additional strength, so got started on fabricating some fiberglass pans for lower and upper seat portions.

Applied some simple aluminum foil to the seat to protect seat and aid in releasing resin, cut the fiberglass mat material (few layers), and got started with applying the resin. When the resin hardened, cut the fiberglass to the required size using an air powered hacksaw. More to follow.

Chassis tubing begins...

Picked up quite a number of lengths of 1.5"x1.5"x.120" square tubing. Our plan is to build out the lower chassis rails and cross-members with the intention of allowing the front and rear S2000 factory sub-frames to bolt into the new chassis.  This strategy will allow both the engine and transmission, and rear suspension assemblies to drop from the bottom while the car is on the lift should full service of either ever be required.

Starting from the rear and working forward, we began by mocking up short lengths of tubing to get an idea of where the factory sub-frame mounting location points would need to be transferred to the tubing.

Fired up the mill and drilled some 1" holes into the tubing into which some 5/8" NF threaded steel bungs were installed and then welded into place. The rear rails also required some short steel spacer blocks to be welded in place in order to permit the rails to clear the rear upper control arm mounts.

Next up was to calculate the necessary angles in the tubing rails required to meet up with the front mounting hole location on the rear sub-frame. Once that was figured out, cut the tubing and welded the sections together.

Used the same approach to start work on the main rear cross-member which also required jog at the mounting pads in order to maintain the desired floor pan depth.

 

Using some heavier gauge metal, bent up some new inner rocker panels and welded them in to the outer factory rocker panels with a series of plug welds. This new panel will be used to mount the chassis floor structure to the body.