Thursday 5 August 2021

First electronic MoT

 I submitted the car for it's MoT yesterday

Apparently I need to contact my dealership re any outstanding safety recalls

Wednesday 4 August 2021

Petrol Pump

 The standard Austin Seven mechanical petrol pump should be adequate for my 3x stock horsepower twin SU petrol guzzling monster. 

The old pump was brand new at the last engine rebuild from A7 workshop. It has 3 problems.

1) It leaks oil from somewhere despite making numerous gaskets for it.

2) Poor starting from cold as the engine has to turn over before it pump delivers any fuel

3) It fails at high temperature on a track day, the thing just stops pumping. The main reason for the upgrade.

The advantages of this pump are as follows

1) Improve cold starting

2) Increased capacity

3) Mounts at the rear stated as ideal application

4) Improved my oil leaks

A blanking plate was needed to remove old pump permanently from the engine, that was fashioned out of 10mm alloy plate.

Here is an Index page for the build

Improved headlights for MoT

 One of my ambitions is to make the car as road legal as possible. One of the key improvements is adequate Headlights. The headlights I had fitted are of the Lucas pattern and are a nice looking vintage type lamp but the lack light cut-off on dip and possibly blinds oncoming traffic and potentially fails an MoT.

The problem being these headlights are in actual fact spotlights off some vintage car, they look the part but are not designed for my application. 


1) Fit some modern aftermarket part

2) Fit a new insert into the existing assembly

3) Get some real A7 headlights

I chose 2)  however the options of sealed beam units or otherwise is extremely limited.

I found a Vespa headlight unit which is almost ideal. It has a focused dip beam, has a parking light and with a bit of effort will take a standard (Bosch) motorcycle 12v headlamp bulb.

The adapter tube was turned out of a piece 127mm x 6.3 mm alloy pipe. Metals4you supplied the material at a reasonable price. The tube just fitted my Myford chuck and an afternoon was spent generating swarf.

The above image shows the 1930's pattern Lucas spot lamp fitted with a Vespa headlight assembly. 

Here is an Index page for the build

Rear Panhard Rod

Rear Panhard Rod 

One of the key elements in my recently improved handling is the Panhard Rod at the rear of an Austin 7 to reduce the oversteer on a corner. The oversteer is produced when the spring bends relative to the chassis as you load it up on a corner. I have tried various arrangements over the years however this is my latest and most successful attempt. The ideal Panhard rod starts off at the end of the spring at the rear and terminates on the bodywork at the same level.  If the attachments are not level with the car at both ends then a movement sideways will be induced into the rear suspension when the suspension is loaded up on a corner.

To achieve the optimum  I fabricated a special clamp on the rear spring and a ball joint on the chassis.

Ball joint on the Chassis

Mounting on the end of the spring

Spring Mounting from below

The spring mounting was fashioned out of two 6mm steel plates held in tension to the spring using 6mm ss cap screws with shims to make the sandwich a tight fit. Locktite was used to assemble on to the spring. This arrangement has been in place for some time now and has not moved.

General Arrangement

Note the kink in the rod to avoid the prop shaft.

The final test was on the track see Video

Here is an Index page for the build

Improved shock absorbers

 The front Shockers

The car on track was still not handling correctly in my opinion, despite upgrading the brakes and steering with added caster angle. My track times at Forrestburn are well off the pace for a properly sorted car.  The problem occurs when there is an abrupt change in camber. The Bowden suspension has an inherent design defect in that the front springs change length under load. This causes bump instability. The steering direction does not change but the tow in/out changes dramatically which is translated by the camber change into bump steer as one side is loaded up on a corner and the other has little grip anyway.

Tony Betts markets a conversion kit for the standard front axel on an Austin Seven to separate the shockers (from each side) and shorten the friction arms.

  As you can see from the following image when this assembly is overplayed on a Bowden arrangement it is about 180mm short on both sides.

The following cardboard model illustrates the type of modification required on my car.

Hopefully I should be able to sell some of the bits when I am finished.

This diagram shows the difference between the two mounting plates

The lower CAD drawing was uploaded to a company in Glasgow (Kilbarchan) called JetCut. The part was cut out of 5mm thick stainless and posted out to me. Some holes were relieved in the fabrication to keep the weight down. The rt angle was welded in ss by myself.

The above image shows the final arrangement installed in the new front suspension arrangement.

The final test was on the track see Video

Here is an Index page for the build

Adding caster to Bowden front suspension

 A theory dictates that high speed stability would be enhanced if the steering had some caster, typically about 6 deg. This was reasonably easily done by inserting a wedge at the mounting point of the front suspension (on the cassis) and extending the lower wish bones to take up the change in dimensions. The wedge was fashioned in a milling machine using 8mm alloy plate and putting a 6 deg slope on the part.

The other item on the list is the lower wishbones that need to be extended.

A jack screw was added to the lower suspension arms to extend them.

The final test was on the track see Video

Here is an Index page for the build

Monday 2 August 2021

Rack and pinion steering conversion

After my relative success at the Bo'ness Revival in September I decided it was time to sort out the steering (including caster angle), Front Shockers and rear suspension.

The steering

The A7 steering arrangement made the car down right dangerous to drive. At speeds above 40 mph it is impossible to keep it on the road. There is so much play in the worm and peg steering box arrangement it is impossible to understand the problems. The existing box has run out of adjustment so a crisis looms for any further track days without urgent action. The alternative is I kill myself. I plan to have a long retirement.

Various solutions have been suggested including a VW steering box however my favoured choice is a Hilman Imp rack from the 1960's. It looked even at an early stage that there was room between the sump and the Bowden assembly for such a modification.

Carboard template of mounting plate for the new steering

Surely there is enough space for a Hilman Imp Rack

A project was born, first the rack mountings were machined out of 10mm alloy plate

Next the cardboard template for the mounting was then cut out of 3mm steel sheet

Above plate needed to centralise the rack vs A7 track rods to keep them the same length.

Above Intermediate Plate needed to transfer  the action of the rack to the front to pick up track rods
Side View Intermediate Plate
Side view of Intermediate Plate

The rack bolted in place with the two plates

Additional plate to take the new track rod ends

Two additional plates are required to mate with the front of the Bowden suspension. The first plate centralises the rack vs the track rods (which are the same size) the other function is to make the assembly easier. The second plate has two 80mm standoffs to transfer the action to the front to pick up the track rods.


The steering has improved a lot however there are now further issues with the handling that need to be investigated and remedied like a) A caster angle of the front suspension (it has none at present) and b) The front shockers are completely ineffective.

The final test was on the track see Video

Here is an Index page for the build