build diary

July 7, 2004:
The 4-1 collector for the factory manifold.
Not too bad for a free part.
entry 427
Using pool hose to mock up the header.
It's quite a challenge getting everything tucked into place.
entry 428

July 8, 2004:
I can feel a thrash looming.
If I want to have this car on the track at the Flyin' Miata Open House in late August, I need to get a few things sorted. Time to get down to work!

The first step is the header. After some playing with pool tubing, I've managed to figure out the best hose routing and arrangement. It was very interesting work as I've never done anything quite like this before. My little Caterham model provided a certain amount of inspiration and confirmed my choice of where to pass through the frame. However, the engine in my car sits much further back than in a Caterham so it was only a starting point. I ended up arranging the pipes differently in the collector. Keith Armstrong also provided me with a link to a wonderful website showing two Caterham exhausts. Of course, I received his email after I'd come up with my design! It wouldn't have changed much, as you can see the difference in engine location from that page. But it has inspired me to try one more change to the #1 tube.

I also decided to pull the radiator to fix a small leak where I had moved one of the fittings. I didn't think this through completely and the entire cooling system drained onto the floor through the water pump outlet. Of course the car is too low to put any sort of pan under there at short notice...
entry 429

The first attempt at a header design.
The arrangement of pipes is the same as the Caterham 4-1 but it's going above the frame diagonal.
entry 430
Attempt number 2 at a header.
This is a basic copy of the Caterham 4-1.
entry 431
The best pipe arrangement for the header.
entry 432
The coolant drained out through the water pump inlet when I disconnected the hose!
I was concerned about the hose on the radiator. Whoops.
entry 433

July 9, 2004:
Brian has a friend who owns a mandrel bender.
The Seven may be going on a little field trip this weekend so we can make the exhaust in that shop. That sure would make life easy so I hope it works out!

I spent last night working on little things. The holes for the passenger's seat base have been drilled - even with all the modifications to the seat, it's still a tight, tight fit and I may have to "clearance" the transmission tunnel a little. I started working on the wiring for the headlight, hazard and turn indicator switches until I ran out of wiring parts. I also reinstalled the radiator, filled it up...then had to remove it again. Turns out I had misidentified the leak. It should be fixed THIS time. I made another mess with the coolant but nowhere near as much as last time.
entry 434

July 10, 2004:
Unfortunately, the plans to visit the shop with the mandrel bender fell through.
The bender has been sold. So I'm back to the original plan of cutting up pre-made bends. Too bad. I expect to ruin a few bends while doing this. I've been working on the wiring in the meantime, getting the final switches in place. Once the transmission tunnel gets here (next week, it's on the way) I'll be able to start assembling big chunks of car. I am tempted to put the side panels on one side of the car so that I can fit the rear fender. This means I can also mount the taillights and start finishing up that particular wiring. First I have to figure out which of the rear fenders is which - they're asymmetrical. I have a number of photos of various CMC builds that should help here.

Interesting note - looking through those old CMC photos, it appears they run their exhaust above the diagonal frame member. That's the first routing I tried but I had trouble getting it to work to my satisfaction. It also put the exhaust close to the master cylinders - but without the change I made to the water pump inlet, it would have been the only option. I also notice that CMC had to cut a new hole for the throttle cable bracket ain the Mitty build as well!
entry 435

More header mockups.
entry 436
I'm trying to get up the nerve to attach one of the side panels.
If I have to take it off again, it will have to be drilled out.
entry 437
The first of the main switches has been added to the car.
These black rockers will be used for the turn indicators, headlights, high/low switch and the hazards. The others will be placed along the transmission cover. This one is the hazard lights and it's currently turned on - thus the illuminated LED.
entry 438

July 12, 2004:
It seems hard to believe, but I'm running out of things to do!
Or more specifically, there's not much I can do until my transmission cover gets here or the exhaust is done. Lots of small things are done now. The lights work (at least those on the front), the fan is now functioning properly, the rear end has been fully aligned and I've started to attach body panels! The big panels are on the passenger's side now and the car is looking good. The fitment of these panels was almost perfect which is a relief. I even managed to get them on with no visible rivets from the side or top of the car. The driver's side will have to wait until the exhaust is done because I have to cut one of the panels. I have another potential lead for the mandrel bending and I'll investigate that today. This is getting quite exciting although there's still some debugging to do once the car is running.
entry 439

Bug mulcher! I think perhaps a small grille of some sort might be a good idea.
entry 440
Fitting a side panel.
This is going to be a difficult part to remove later as it wraps right over the top rail.
entry 441
The side panel in place.
It fit almost perfectly.
entry 442
The side of the car.
There is a seam right below the cleco fastener in front of the firewall. CMC puts rivets down here but mine has a very tight fit without them. Good, this makes for a cleaner look.
entry 443
The front fender on an unmodified stay.
entry 444
This is where I would like the fender to sit.
entry 445
The angle of this stay was all wrong.
A quick pie cut solved that although it still needs to be extended a little.
entry 446

July 13, 2004:
After a lot of running around, I've determined that there aren't any real mandrel benders in town.
After a long talk with a local petrolhead and muffler shop wizard, I've decided to simply use "normal" pipe bends in the first round of my header. It'll be inexpensive, easy and will let me get the car running. Besides, I'm using quite large 1.75" tube for the header instead of the more usual 1.5". Even with the lower quality bends, the tube will never go below 1.5" diameter. Once I'm satisfied, I can cut and weld my own runners out of mandrel U bends.

To this end and following advice given to me, I spent last night carefully bending welding rod into the shapes I need. I have a lot of room to work with and it's a good thing - this is harder than it looks! The bent-up rods were dropped off at the muffler shop this morning and I'll be able to test-fit them tonight. A couple of my bends were too tight for their bender but I do have a few chunks of mandrel U in that radius so I'll just stitch that together.

In other news, I ordered my mirrors last night. I had been looking at the same mirrors we used on the Flyin' Miata "Track Dog" race car but the $80 price tag for a pair had me hesitating. A bit of looking around and I found some motorcycle mirrors that are similar in design for $25 a pair. So they're not quite as easily adjusted. I can deal with that! I was also informed that there's a track day that would be perfect for testing and setup on the 24th. Will I be able to make it? Hard to say. It's a long drive and I'd hate to discover a major problem when I got there. But it honestly would be possible if I wanted to do it...
entry 447

A modifed front fender stay.
It's been angled up by about 25 degrees and extended by 20 mm.
entry 448
The bias bar control cable was placed a little too low and too far back.
It's much better now. Note the BRG nuts holding the brake pedal down - a little reminder of the donor car.
entry 449
Once the header pipe routing was worked out with the blue hoses, aluminum welding rod was used to finalise the shape.
It's quite an art!
entry 450
My future header tubes.
entry 451
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