I was given a clue! Lose a bit from
the rear brakes or get a bit more on the front. One
section above that shows the brake efficiency at 53.78% front
and 45.78% on the rear, means they are too close so that when
weight transfer happens the rear would lock before the front and
could lead to a spin.
One way to sort the problem would have been to use an adjustable
regulator to the rear brakes. This is no longer allowed
for IVA even if it is then locked when done. So another
way has been sought.
It took a lot to figure the weight transfer, or weight
distribution ratio as mentioned above, but the Internet came to
the rescue and after some searching for answers, I was able to
write a spreadsheet, enter the data from weights and braking
forces and for it to work out the end results as above.
The next step is to solve the problem and after talking with a
rep from Brake Engineering I have decided to reduce the rear
slave cylinder size.
The standard Sierra cylinder has a bore of 22.22mm, but there
are other cylinders that match the external dimensions but have
bore sizes of 20.64 mm 19.05 mm and 17.46 mm. So the
spread sheet was changed to allow me to work out the brake
forces that would act on the back wheels, all else staying the
same. This allowed me to make theoretical changes and
watch the predicted brake distribution and weight distribution
The spreadsheet is here for anyone to try: - braketest.xls
I have chosen to fit the 19.05 mm rear cylinders, which I hope
will give me an approx 60/40 split on the front/rear
brakes. This is work in progress.
Interior fittings. Side repeater body and N/S and
. These must also follow if above 3.2 mm
from the bodywork have the 2.5 mm rule. These have now
been covered by rubber hose to solve this issue, this is glued
into position over foam on the body of the repeaters. The
repeaters them selves give me another problem elsewhere!
More to follow!
19th October 2009
Picture of the new brake switch adapter that should allow air to
be bled from the system.
Seat Strength For outboard seats the height
of the top of the head restraint above the R point must be at
least 700 mm.
Now this equates to 753 mm from
the seat area on a line parallel to the seat back! The
problem arises in that my seats are designed to fold down flat
and the headrest will go very low to achieve this. The fix
is to sleeve the head restraint bars, so that the head rest will
not go fully down into the seat. It means the head rest
may have to be removed to fold the seat down, but so be it.
All ‘hard’ parts
contactable with a 100mm sphere, which form an external
surface or protrude 5mm or more from the external surface must
have a radius of curvature of at least 2.5mm
Mounts/Rear reflectors and Interior mirror
This 100 mm sphere that represents a knee coming into impact
with the car, can come in from any angle, no longer from just a
forward direction, otherwise the headlight mounts would be
covered by the front indicator lights.
The bar that holds the headlights has been redesigned. It
is also wider to give more spacing between the front indicators
as I am still loathe to mount them from the nose cone. A
small amount of lathe work is still to be done in making two end
caps, but that job is all but complete.
The two rear reflectors, the 60 mm red disks on the back of the
rear arches are 6.2 mm thick and the rounded edge does not
conform to 2.5 mm radius. It was suggested that I glue a
large O ring on each of them, but I am looking to make two
aluminium bezels. My reasoning is that any trim fitted to
solve an issue will not be falling off after IVA.
The interior mirror has an edge of 1 mm plastic and the edge
facing the driver needs to have a 2.5 mm radius, so I will
either fit some form of edge trim or get another convex mirror
that will pass.
The front indicators are
positioned more than 400 mm inboard widest part
& Angles of visibility
on side repeaters not met
I could have kicked myself over this! The rear wings are
the widest part of the car and these are the second pair of
wings the moulds for the first set were wrong. These new
wings are an inch wider then original, so they add approx 50 mm
to the width of the car. The indicators were over the 400
mm distance per side by 15 mm but would have been fine for
the original wings. This has now been sorted by the
new headlight bracket.
The side repeaters need to be seen from an angle of 5 degrees to
60 degrees rearward of the vehicle along a line formed by the
extreme outer edge. This outer edge is made by the rear
arches, and so the only way for the side repeaters to meet
the requirements is for them to be mounted on the outside edge
of the rear arches. But does that make the car wider still?
This is still under review and I need to ask again of the
inspection team for an answer.
Rear Fog Lights RS3, RS4 & RS6
all due to the wiring loom as supplied, compliant for the SVA,
but not IVA. The fog lights could be switched on from the
side light position and not just the headlights. The RS10 & RS11
to the tell tale light. It had one but the wrong light,
the switch would light up, but you could only notice it in the
dark so not good enough. This has been partly fixed by an
earth return from the headlight position of the indicator
stalks, this will feed a relay through the fog light
switch to only switch the rear light on correctly. I have
ordered a tell tale light that has the correct symbol and can be
seen under daylight conditions.
Rear suspension ball joints
not fitted with lock nuts
. OK, so other builders
of the Roadster will know there are no ball joints on the rear
suspension, but it means the rear camber adjusters. These
are 20 mm threaded bars that fit into the top wishbone, they can
not rotate and become loose, but fitting lock nuts will stop any
wear happening to the threads. A valid point, I have now got the
lock nuts and will fit when the rear axle come off to fit the
new brake cylinders.
RS7 wiring under dash /
Protect battery terminals / wiring passing through
un-grommeted holes at headlight mountings/front cone
Wiring under dash now sorted, more insulation tape around wires
as in a normal car loom and a few more tie raps used. The
un-grommeted holes I have sorted with the new headlight
mount. Still to find battery terminal covers or a complete
cover for the battery.
23rd October 2009
Fitted the new brake switch adapter today, also the switch,
relay and lamp for the fog light. Took a trip down to a
few breakers yards to get some battery terminal covers and also
swapped the offside rear brake cylinder for the smaller size and
fitted the lock nut to the top wishbone. If the weather
holds tomorrow I will do the near side.
Here is a picture of the modufied headlight bracket showing how
I solved the sharp edge problem, still to make the end cap and
come up with a tidier way to hold the cable to the indicator, it
could run internal I guess.
The silver nut at the bottom will have a 12 mm nut cover fitted.
24th October 2009
Finished the rear brake cylinders and lock-nuts on the
wishbones. Filled and bled the brake lines, the Easybleed
make life easy when doing it on your own. Car is still on
the trailer so no chance to try the brakes yet.
Made the aluminium bezels for the rear reflectors, not sure if I
will use them! They look fine, but have seen some nice
chrome finished reflectors from SVC, so if I get chance to see a
few I may pick them up. Managed to scrounge some rubber
sheet for the battery top so that is now covered
6th November 2009
OK so a little while since last update, but I have been busy
Now I hope to have all the points covered, but only time and
retest will tell me if it is enough. The secondary side
repeaters have been fitted to the wings, small lamps in the
Not sure if you will notice it or not in the next picture?
The headrests have the tubing fitted and glued to stop them
retracting in too far. The battery cover with terminal
covers. Then there is the rubber piece over the internal
body of the normal side repeaters. The wires have also
been rapped and tie rapped to the frame.
The centre mirror was edged with grommet strip and then a cable
cover glued over the top to finish. Another close up of
the headlight bracket, now with it's end plug. Lastly the
locknut on the rear camber adjuster.
I did buy some different rear reflectors, but to be honest
prefer my own. Will take the car to a garage Saturday to
test the brakes, it will not be a comprehensive test as with the
IVA, but hope to get figures from it all the same.
11th November 2009
The brake tests on standard MOT rollers gave indications of back
breaks locking at around 100 Kg and front around 130 Kg,
unfortunately no way of indicating balance and the point at
which they lock up is dependent on the weight of the axle.
So having a re-think on this and trying to figure a way of
measuring brake pedal force easily.
To that end I came up with this!
A clutch slave cylinder from a Honda motorbike and a pressure
gauge. Due to the cylinder size, 2 bar indicated is approx
23 Kg pressure on the pedal. This needs to be a higher
figure so an addition of a spring should help. The idea is
to strap the cylinder to the base of the foot and read the pedal
pressure on the gauge. It does not need to be accurate
just repeatable so the same effort can be applied at various
stages to test both axles.
Changed my idea for the new side repeaters. At an auto
jumble I spotted another variety of small amber lamp
holders, and bulbs for them arrived in the post today.
They are a lot brighter and give a better viewing angle as you
can see from this simple 12 volt battery test.
I should have them fitted tomorrow night. These have
removable lenses so makes it a lot easier when you need to fit
replacement bulbs. Silicone sealant will be used on the inside
of the wing and the smaller size will give more clearance from
16th November 2009
Completed fitting the lamps over the weekend, once again I bled
the brakes to ensure no air came out of the system, there was
none but needed to be sure. I managed to book my IVA
retest for the 23rd
So now it is just a matter of waiting, and keeping my fingers
Thought I would post a picture of the lights fitted, would like
comments as to suitability if possible.
So here we have the new light fitted, not as
The second view is looking under the wing, you can see one of
the clips that holds the plastic tube with the wire s running
internally and the end of the lamp holder covered in silicone,
plenty of clearance from the tyre.
When I last took the car out on the trailer, the tarp I used
caused a lot of scratches on the rear arches and bonnet.
So I treated the car to a small car cover, it is not
tailor fitted but a standard small car size costing about
£19. I will used elasticated straps under the car to
pull it tight so should provide better protection?
23rd November 2009
The car has passed retest. All the time now seems
to be worth it and I can look forward to getting the
registration number, taxing the car to finally drive it on the
road. Bit out of season, but hope to get some good days.
Just a couple of pictures to close the pages off, two of the car
at the centre, wet!
Next the main one, a copy of a copy of the IVA test certificate
with a few bits blanked out. The main one is now with