• Ripault bonnet catches (4)
• Bonnet webbing
• Radiator shell
• Radiator cap & badge
• Radiator grill
• Radiator shell lower mounting brackets (“Z” brackets) - (2)
• 5/16” UNF x 3/4” bolts & nyloc nuts (2)
• M10 nuts (4)
• M10 spring washers (2)
• 2BA x 1/2” countersunk screws (2)
• M6 x 15mm bolts, nuts and spring washers (4)
• M4 x 10mm chrome headed (or polished SS) domed countersunk screws & nyloc nuts (16)
• 3mm alloy pop rivets – for temporary use (16)
7.2.1 Bonnet details
The bonnet is handmade in 4 louvered aluminium panels, two top panels and two side. The long edges of the
panels are folded in a “U” section. These are held together by three stainless steel piano hinges whose edges
are similarly folded and slide into the panels. The top hinge is held in place by 4 alloy rivets, and each side
hinge by 6 alloy rivets, 16 in all. Through each piano hinge is a brass rod, which can be removed to
dismantle the bonnet. The centre (larger) hinge has a 5/16” brass rod. It is fixed to the car at the rear with an
end fitting having an M6 stud passing through the bulkhead and held with a nyloc nut. The front is fixed by
an end fitting which is attached by 2BA screws through the radiator shell into the radiator hoop. The two
outer (smaller) hinges have a ¼” brass rod and attach the side panels to the top panels. To the lower edge of
each side panel are fixed two “Ripault” bonnet catches which mate with hooks fixed to the chassis rail.
7.2.2 Bonnet fitting/cutting advice
Fitting the bonnet may seem a daunting task for those tackling it for the first time. However it requires more
patience than skill to achieve a successful result. Remember to check and double check all dimensions before
cutting any metal. Aim to trim a little at a time, check fitting the panels at each stage. Metal can easily be
removed but not added. Filing rather than cutting the last 1mm is a sound strategy if somewhat laborious.
It is most important to the overall appearance of the car that the shut lines (the gaps between the bonnet
panels and the body and radiator shell) are consistent.
The eye will pick up any lack of evenness. Consistency is much more important than the absolute value.
However a gap of at least 3mm is necessary. Any less than this and movement of the panels with the car in
motion can cause the edge of the panel to contact the bodywork and chip the paint. 3mm is a good aim (a £1
coin is a useful gauge).
The aluminium panels are very soft and will deform and scratch very easily detracting from the finished
presentation. The utmost care is required when handling and cutting them. Always carry the panels one at a
time taking care not to knock them on anything. Always work with them on a bench covered with soft carpet.
7.2.3 Preparing centre hinge
The first step is to prepare the hinges. The centre (
larger) hinge must have an overall length of 49 ¼“
including the two end fittings (front & rear), which are each 1” long so the stainless steel part of the hinge
must be 47 ¼“ long. The 5/16” brass rod must be longer, just a little less than 49 ¼” to accommodate the end
fittings. Cut the stainless steel part to exactly 47 ¼ “. It pays to measure, check and measure again before
cutting. Be careful to pull the brass rod out of the hinge a little way so you are not cutting it and cut squarely
in both planes. Now slide the brass rod back into the full length of the hinge and cut it to length so that the
two end fittings mate with the ends of the hinge when assembled. Drill four 4 holes to accept the 3mm pop
rivets, 2 in each “U” section 20 mm from the ends of the hinge. Each set of holes must be deburred so that
the aluminium panels can slide easily into place. Do this with a hacksaw blade for the inner surfaces and a
countersink bit for the outer surfaces. Suffolk Sportscars usually does this for you.
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