First Stevens Prototype Restoration – Part 1

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Stevens Sienna prototype

It started with a sketch in 1976 but the yellow finish didn’t survive

For many years I have endured a hankering for a little ‘Special’ the type made popular by the minimal machines such as the Austin Seven. The post war idea of building a racing special became very popular and I received further inspiration after meeting the master of the Austin special, Chris Gould.  From his house near Worthing, Chris made fibre glass Ulster bodies over many years but like everything it came down to price. Buying one completed was out of my range for sure, whilst building my own version didn’t really appeal and would still exceed my budget. Several years ago I met up with Tony Stevens at his home in Kent and we visited the unit where many of the sports cars he designed and built during the 1970s and 80s were still kept. At the back of his workshop and untouched for years was a very small two seater sports car called the Stevens Sienna. After many years designing cars for Rootes Group, Tony decided to produce his own cars which culminated in the Stevens Cipher range displayed at the Earls Court Motor show in 1980; the Sienna was his first built prototype. In his own words Tony describes the Sienna as a car that ‘neither he nor the public wanted at that time’ but forty years on, times have changed and so will the car. So what is it exactly you may ask? Well there were close ties between the Reliant factory and Tony Stevens during the period so when considering the basis for his creation, a chassis from the Tamworth based company was sourced. Heavily modified for both minimal flex and to accept the bespoke body, a Kitten chassis was prepared which meant the excellent Reliant 850cc in line four cylinder motor could be used without much alteration.
Stevens Sienna prototype restoration

Time to remove the body and see just what we have, the answer could be better

This very engine is now a popular alternative as a replacement into original Austin 7s, the reason being they share the same distant gene pool; let me explain. When Reliant needed a four cylinder unit prior to WW2 it was the Austin 747cc power plant they bought in but when Austin decided to cease production Reliant assembled their own version. This engine was developed over the decades and offered reliability with ease of maintenance. The 850cc version arrived in the 70s and the combination with the Kitten chassis seemed ideal for the Stevens prototype which would become known as the Sienna. First registered in April 1977, with the help of Simon Fitch of Stevens-Cipher Enthusiasts Group/Reliant Kitten Register we established that the engine was dated to May 76; our aim is to have that unit up and running for its 40th birthday. Re-store and Re-age? The seventies was no doubt a dire time for car design, the individualism of marques began to disappear and any flair or character was penned out on the drawing boards. Mass produced square boxes left the plants of Ford and Vauxhall; worst still, for a decade very few BL cars  could be described as attractive. The Sienna was certainly not going to win any beauty contests and unlike the Cipher that followed, it didn’t fall into either the modern age or a bygone era. ‘A squashed Morgan’ were my thoughts when first viewing Stevens prototype but minus the charm of the Malvern produced machines. Nevertheless it intrigued me and therefore ended up in my garage but this time I wouldn’t be chasing the original perfection that has come with previous rebuilds. This time I am looking at what I feel the car should have been whilst satisfying my desire for a light, fun and unusual ‘special’. The fabric roof was not a great design and I think Tony would acknowledge that, it served a purpose, luckily one I don’t require, so that can go. The windscreen then becomes somewhat redundant and everyone knows any ‘special’ benefits from a pair of early aero screens. The Sienna Special in my ‘mind’s eye’ may not please owners of the real thing or in fact the purist but it needs to be something I can enjoy whilst ensuring the project can always be returned to its original design; should a future owner look at that route. Many months of contemplation have passed and it is time to get started. I am sure most folk would agree that before taking the Sienna apart it would be sensible to check the health of its 850cc power plant; that would turn out to be anything but straight forward. Back from the Brink?
Not the surface of Mars; leave a tank full of fuel for 20 years this happens

Not the surface of Mars; leave a tank full of fuel for 20 years this happens

We had oil and water but were minus two other key ingredients; a spark and fuel. The fuel tank had a drain bolt and I was treated to a face full of brown foul smelling gunge. Fresh fuel and still nothing, the single SU was not seeing anything so we decided the pump was not working and plumped for a more direct route; syphon into tube onto carb. Plug replacement was another straight forward task until I tried to move no1 which was seized solid; oh dear, ‘Don’t panic, just get a bigger bar’ advised my long suffering mentor Alan and with the biggest breaker bar and much straining it moved. Fighting all the way, it took 30 minutes to extract and whilst fully expecting the threads and maybe half the cylinder head to come out with it, the worse failed to materialise; the thread on the plug was in very poor condition but intact.
Stevens Sienna prototype interior

Interior needs a re think especially after decades of neglect

Alan was now bored and wandered off to play with another plug; removing the electrode he then got me to hack saw straight down the middle.  ‘An old boy’s trick’ he advised whilst cleaning the threads on the wire wheel, ‘this will clear out whatever is there and a new plug should fit nicely’. The trick is slowly wind in and out, surprisingly it worked, and the tiny 850cc beast roared into life. Blocked fuel lines were traced back to the tank and once removed a look inside can only be described as horrific. We cleared the lines with earth wire from a large capacity electric cable, the tank itself would need 8 large bottles of ASDA white vinegar and a box of baking soda; one clean tank for £4.68.  Another method from the minds of men that always have dirty fingernails and are happiest in the garden shed; there is even a tutorial from ‘Chuck’ on ‘You Tube’. So, the engine ran for a few minutes before we noted the temperature gauge was climbing quicker than the rev counter due to a failed water pump.  Switched off the motor ticked itself cool having not been run for many years (maybe decades), we are certainly on our way. Grant Ford for – Next Instalment: We undress the Sienna and get down to some rather rusting metal The engine is cooled by a classy classic radiator Cut and weld, we’ve been here beforeTags: