Rear axle and suspension fabrication 12 Dec 2009

Time to start the suspension then. I began to make the U brackets from 50mm x 50mm box section.Marked up and sliced through and then the waste side chopped out. They were then divided to form rough cut brackets

 

Once i had these sliced up, i made a template out of sheet steel which i could then use to reproduce a good shape and centre punch them for drilling

 

With the rear axle prepared i made some brackets from 50mm x 50 mm box section and cut out semicircles so that they would fit snugly around the axle. My U brackets were attached to the chassis according to the book.

My red trailing arms were manufactured using a jig so that they are all the exact same length (x4). My bush tubes welded onto the ends and bushes fitted, the axle, brackets and trailing arms were assembled and the axle clamped into place so that it was centred perfectly. Everything was then welded into place.

 

 wooden boards were used to raise the axle up so that the trailing arms were parralel to the ground

  

I made sure that the axle casing was square using a spirit level on the diff mounting face before welding

 

Top rear shock mounting plates made from 3mm sheet steel 100x100mm and a length of 19mm box section along one edge. Also 2 plates welded on to accomodate shocker bush

Top rear shock absorber plates were then mounted ensuring that they were flat.

I bought a pipe bender but struggled to bend the thin 1.6mm tube required for the rear body hoop. After a quick look on t'internet i found that if you fill the tube with water and then pour in sand, the sand will sink to the bottom and displace the water until the tube is full of sand. The tube can then be cappend and bent much easier. To aid even more, i used Oxy Acetylene to heat the tube up to cherry red at the area which needed bending (WARNING  -  too much heat on a short tube can cause the water to turn immediately to steam causing the steam and red hot sand to exit the tube VERY rapidly)

Then attached the bent hoop to the rear of the top shocker mount plates and levelled it up using clamps and wood.

Rear suspension done!!!!!

Next job was to make the suspension bush assemblies. The "book" advises the use of metalastic bushes from a triumph herald or similar but i wanted something with more performance so i decided that polyurethane was the way forward.A full set of bushes, tubes, brackets and bolts can be bought locally for about $360 AUD but i wanted to manufacture them myself so i spent a lot of time researching poly bushes, their suppliers and prices and was surprised at the high prices but eventually found a suitable solution.

Surprisingly the closest bush i could find to the size i wanted is a set designed for steering rack mounts on an EA Ford Falcon. The only modification i had to make to these is to remove 2 mm from the shoulder of the bush and shorten the crush tube to fit within the brackets i had made.

The outer tube (eye) is ERW (electronic resistance welded) mild steel tube with OD (outside diameter of 34 mm. I had to machine these on my friend's lathe to A: remove the weld protruding inside, B: remove ovality C: create a smooth inner surface for the bush.Here we see machined eyes on the left and unmachined on the right.the finished eye. You can still see where the weld is inside the tube but it is smooth enough for mounting the bushes. A Day's work machining the eyes, crush tubes and bushes. Glad it's done and satisfied that i have made them myself. Total cost is about $120 including brackets which is a big saving from $360. Nice result!

Started to recon the MKII Escort rear axle.
Used the robowash at work to clean most of the thick stuff off everything as there was a lot of oil mixed with red dust which sets like concrete. The robowash also took most of the paint from the axle casing too. Then cleaned all the rust off with sanding discs and rotary wire brushes. A coat of etch primer and enamel should make these look like new!?

I was amazed how well these scrubbed up actually because cars this old in England are just rotten!

A Test Fit?

With the main frame complete and looking great, we decided to see what the finished product would look like (some imagination necessary)

At this point i would say that the frame still only weighed about 15 to 20 kilos!

Strengthening added to chassis 26th April 09

more chassis

Continuing with the chassis.

uprights,

jig was made for front parrallellogram thingie....very fiddly!

Chassis started!11 april 2009

started chopping and laying out the 25mmx 25mm box steel on the building table to construct the floor.

Home made chop saw

I'm too cheap to buy a chop saw so i modified my angle grinder to suit.
I bolted my drill press vice to a piece of board and screwed down a piece of steel at 90 degrees to that. i bolted my gronder to a piece of 2 inch box section and squared it up. i could then slide the grinder along the steel on the board to cut a perfect square edge on box section.
I then could measure and mark other angles on the board and move the guide as necessary to reproduce accurate angles! easy!

The build begins 5th May 2009

I have decided to build a car based on the Lotus 7 design. If you are not familiar with this name, you have probably heard of similar cars like Westfield, Caterham, Dax Rush, Robin Hood. These are all kit cars but the car i intend to build is made completely from bought and found steel and various bits from several different cars. At this point, nothing is set in stone about the final product, although i am following rough guidelines set out in a book entitled "Build Your Own Sports Car For As Little As 250 pounds (and race it)"

This book tells you how to manufacture the basic chassis and is focussed on using a MkII Ford escort as a single Donor. Unfortunately, here in Australia, this is not an option due to strict emmissions, safety and design rules applicable to independantly constructed vehicles. Instead, we are forced to think outside the box (or book) and use donor cars, parts, materials and design features which are available locally, cost effective and are viable options with regard to local design rules. For example, the "book chassis" will not pass the torsional rigidity regulations here in Australia so additional strengthening must be factored in. In England, it is possible to use the crossflow engine from the donor escort, or use carburettors but here our engines must pass emmissions tests as per 1998 regulations so we must use engines from cars built after this date and use their original (or better) fuel and emmissions equipment.

So with this in mind, i will start my build and look for suitable donor parts along the way!

1st step is the table......

Built the building table, all marked out and ready to start! (VERY EXCITING!)