Читать книгу I'm Building a Car - Andrew Davies - Страница 5

Assembly, construction design, re design re design.

I’ve planned 2011 to be the year, well as I write maybe, in February the authorities changed the rules on personally built cars, how that will effect the build remains to be seem, I’m too far committed to make major changes so I will persevere. I believe that considering I’m engineering the car to a high level, following the ASRF guide lines and putting safety first that logic will preval.

The body has been off for prepping, a expensive venture, but the body has been transformed into a smooth and aligned structure, not only do the doors fit but the whole shape has been enhanced into a stelth bomber, well car!

Body after some repairs, as delivered was poor.

2011 has seen the fuel system developed, a former LPG tank has been suitably converted, heat shielding to the exhaust system for obvious reasons, cooling system, fans, power considerations, where to place the battery, loom fuse boxes all these items need consideration. Its worth remembering that once the body is on some of these ancillaries will be hard to work on so a lot of work at this stage.

Before the body goes on finally I will run up the engine and check everything, so far so good but a big snag hit with the brakes and hydraulics.

After plumbing upon the clutch I found I needed about 50Kg of load to release it, not overly practical! This necessitates a smaller master cylinder, more travel but less load at the pedal, applying this to the brakes and after doing a few calculations regarding front/ rear bias I figured my had too much rear brake action and possibly inadequate pedal advantage. Here’s where being an engineer comes in handy, books, calculations, calculators, web sites etc. Yes I want the answer to 3 decimal places but in reality that’s not really possible so its going to be a bit of suck and see.

My calculations suggested that a maximum braking say 1.5+G, 90% of the brake effort will be at the front, and the tall 16 inch period wheels I’m using will exasperate the problem as the moment increases on the small brakes.

The braking venture has seen a new pedal assembly developed in order to achieve > 5:1 pedal effort, different master cylinders for front an rear, plus a rear adjustable pressure regulator valve. But will it all work, lets hope!

There’s a lot of tinkering at this stage, a bit of cosmetic, wiring lights, number plates, where are they going? Small parts but costs do add up, period lights are not easy to come by and not cheap, instruments, getting closer though.

Time to put some fluid in the beast, completed the cooling system and added coolant, to my dismay water leaked from head gasket and water pump. The water pumps already been rebuild as was rubbish when supplied, no go its to porous so decided to adapt to a newer series 3 water pump with larger impeller and more sturdy design, some design enhancements coming. Head was a worry but after re torqueing the head leaks disappeared. Goal is to start the engine, test for pressure, cooling etc, much easier to get to whilst body is off, if all is well will attempt to move under it’s own steam and stop with the revised brakes.

Plans change, now lets get the engine fired up prior to the body, just in case, so that means all fluids, cooling fuel, exhaust and brakes MUST be working, possibly a good way forward as once the body is on its not coming off!

Now I ‘ve a new factory to build so things slow down considerably.

After a bit of tinkering and catch-up, I’ve made the decision to start the car, so it’s wiring fun time, ignition, start action, after a few goes I realize the distributor is shorted, a few more rounds and she fires, what a sound, just like a 50’s racer, just what I wanted, but then she stops and fuel squirts everywhere. Interestingly Jaguar installed a non-return valve on the auxiliary starting carburetor in the 60’s, but not on my engine, so a modified valve goes on and the problems sorted.

Mighty fun to drive like this!

In September its the big move, Ash and I hire a trailer and tow the DBR2 to it’s new workshop at Enterprise Drive, we call it the “cool room”, well it’s made of cool room material and houses a pretty cool car. My hoist is in so it will be much easier to work on the car. All went well until the hand brake cable came adrift, not so easy to hold the car, but the hydraulics held up and all was fine, but it’s’ now heavy!

More wiring, kill switches, roll over inertia switch installed this is going to be as safe as I can make it. A few more starts just for fun, now brakes are bleed again and the steering rack removed and shortened in order to achieve the correct toe in, a professional wheel alignment follows and to my credit the rear is perfect, yes perfect no adjustment needed at all so just goes to show that a ruler and straight edge are just as good as a laser!

So a test drive is warranted, around the car park of course and success, ok it takes a while to start but once running she’s fine, if not revving a little fast but everything works, the brakes the steering, the clutch, gears all fine, well so far.

Ok, lets do that again, and again!

December 2012 --

Goal to fit the body to the chassis – last time, or 13th time to be exact, but at least it will be right, the body has been sitting on the cradle which held the GPR rigid so it could be prepped, this jig is a work of art in it self and a real shame to destroy, but off came the body in late December, fitting was easy just slip it over nose first and “Allah’ it’s a car!

Early 2013 saw the permanence of the body.

Getting to know the family.