Chassis as delivered.
Section V Preparation of the Chassis
Safety Note :- Before you proceed any further you are strongly advised to read the article by Tim Swatt in the Winter 2006 Issue of Boys in Hoods page 18. This describes an essential modification to the mounting brackets on the Sierra Trailing Arms. This modification can be carried out on a finished car but is 100% easier if done NOW.
Warning:- Before carrying out any modifications to the standard design seek written approval from the Kit Designer. Use only high quality materials and fasteners and lock all threads. This applies particularly to Safety Critical items such as Brakes, Steering & Suspension Components. The chassis is best placed upside down on the garage floor, the Roll Bar giving a very firm support at the rear. Place the Roll Bar on some thick cloth or towel to avoid any damage, do the same at the front end.
See Appendix V Special Tools Required before starting.
The weld areas should be wire brushed with an electric drill and a rotary wire brush, ( try to get brushes with Stainless Steel wire and use goggles ) to remove all trace of oxidation. Chip or file off any weld spatter, the bare hand can detect even the most minute little blob. Take care to avoid cuts. Once this is completed, at least on the visible lower faces, the upper faces can be completed once the chassis is turned over. Do not turn over yet. It is also a good idea to run a file over the edges of any tube ends or sheet metal to remove burrs etc. RHSC's recommend drilling 3mm drain holes at the lowest points of the chassis, particularly on the Mild Steel version to allow water to drain out, poke the holes clear at intervals.
When fitting Coil overs at the rear, the lower ends of the Roll Bar need cutting off. This is a good time to do this.
On my chassis cutting off just 45mm was fine. If you do not wish to take my word for the 45mm, you will need to wait until the Rear suspension is fully fitted with the Engine and Gearbox, Fuel Tank, Seats etc installed, plus at least one passenger. See section XV Fuel Tank & Boot
Where possible polish the bare stainless with fine " Blue Back " Engineers emery cloth or use the 3M Brown Polishing Mops. Use the Diablo method, rip off a piece about 1/2" wide along the length of the sheet, wrap around the chassis once and pull backwards and forwards at right angles to the tube whilst moving along the tube at the same time. A nice fine uniform finish can be achieved in a very short time. As the Roll bar is the only part of the chassis visible on the finished car, extra care can be taken on this part later on when the chassis is turned over. You can buy rolls of narrow abrasive cloth at most Kit Car shows.
Some builders have opted to undercoat and gloss even the Stainless Steel version. Contrary to popular opinion Stainless steel will " rust " or discolour but to a much lesser degree than ordinary mild steel. The choice is yours. It is a good idea, even with Stainless steel to give the car a good hose down after a winter run with tap water, but hard water may leave stains, so wipe the panels dry. This more or less completes the work on the bare chassis.
Note:- A problem that only manifests itself when the mudguards are fitted, is that the rear wheels tend to be slightly offset. The offside wheel projecting out about 10mm more than the nearside. There does not seem to be a lot that can be done to correct this apart from fitting a nearside rear wheel spacer. Later chassis's are fully jig built and this error may have been corrected. See the sections on Rear Axle and Mudguards
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Chassis as delivered.
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© Colin Usher 2005