MK1-Performance-Conversions.co.uk
The most comprehensive resource for the early mini fan anywhere

Downton Bolt on Tuning Kits.


Each of the "Bolt on kits developed by Downton went through the same careful development process, this is described by long time Downton employee Mr Barry Hawkins.


A Downton, Bolt-on:


Always carefully overseen by Daniel Richmond.


When a new BMC model came out, say a new 'A' series, Downton would take the engine apart and if the car was going to remain as a demonstrator the crankshaft/flywheel assembly would be balanced, the engine would have the head faced to increase the compression, say 10-1 then ground and ported by George toth and the valves would have their heads machined in the machine shop.


George would also skillfully reseat the valves. The head would then go to Fred Stokes for careful calibration (with pipette and paraffin oil) then onward for assembling, at which time all Downton heads had the end top face stamped by Fred with comp ratio and reference number.


Jim Penton (foreman welder) would have the car and by trial and error carefully workout the shape for a three branch exhaust manifold then onto the rest of the exhaust system (silencers where bought in from Burgess silencers in Leicester). All the bolt-on Downton kits used BMC cast aluminium inlet manifolds. George in the head shop ground them out to match the inlet ports on the head and they had location pins fitted. For the competition engines Jim would produce an inlet manifold in tube for Robin Fearon, who would then fit linkages and say for example, twin H4 SU carbs, heat shields and aircleaners.


The distributors where usually changed for non vac types.


All this process would take a couple of weeks, sometimes the guy's would stay on into the evening until the job was done with Daniel carefully watching every move.


The car would then all be put back together and Daniel would try the car with the foreman mechanic on our test route complete with fifth wheel for speed accuracy. This was always a touchy time, Daniel had a good ear and a fine touch with engines, so nothing would ever get by unless it was absolutely correct.


Eventually all the bits would come off again and jigs made and and if necessary an aluminium inlet manifold cast (an outside company job).


The completed new kit would then be fitted and again go through a full Daniel test and again Daniel would be up and down the test route time and time again each time testing various SU needles etc. Not until he was fully satisfied did we all relax a little.


At the end of this process I would get all the parts together and do the costing and make the specification sheets up. Daniel and Bunty always trusted me with this side of the business.


Downton never cheated as far as performance figures were concerned.


Please note over my time at Downton some of these jobs where done by different people (apart form the very much liked Fred Stokes who was older than

          the rest of us) so every time you look at a real Downton head you will

          know it was Fred that put those numbers on the end of it

        


The Brochure Archive
An archive of original brochures & what went into making them.


The Downton Brochure


Produced in 1969 this semi glossy brochure was the most interesting brochure ever produced by Downton.  It gives a fantastic insight into the company & is a fascinating read.

Mini, Cooper & Cooper “S” Brochures
Brochures for the whole Mini range.



























Conversions for the 850 Mini










Mini Ton Bomb Conversion


850 Mini 1960
850 Mini 1964
850 Mini 1966
No’s 1 & 3 Touring
Conversion 1966
850 Mini 1969
Elf / Hornet 1966
850 Mini 1969
Mini 100 1969
Mini Cooper 1961
No’s 4 & 5 Touring
Conversion 1966
No’s 4 & 5 Touring
Conversion 1969
No’s 4 & 5 Touring
Conversion 1973
Mini, Cooper & Cooper “S” Competition Tuning Brochures
Tuning specifically for competition.






Group 2 Conversion
Group 2 Conversion
Britax / Downton Cooper
Handout














BMC 1100 & 1300 Range
Tuning for BMC’s most popular model.
No’s 6, 7 & 8
Conversions
No 22
Conversion
No 32
Conversion
1100 Motorway
Conversion
1100
Conversions







BMC 1800 Range
Tuning options for the “Big” Transverse model.
No 14
Conversion
No’s 13 & 14
Brochure



























B Series Conversions

Sports Cars
Tuning options for various BMC & Non BMC Sports Cars..
Austin Healey Sprite
Conversions.
Austin Healey Sprite
Conversions.
Lotus Seven
Conversions.
Lotus Seven
Conversions.
Austin Healey Sprite
MK2 & 3 Conversions
MG B GT
Conversions.
MG B GT
Conversions.
Sprite MK4
Conversions.
MG C Conversions
MG C Conversions.
Early B Series
Conversions.
Other BMC Models
A collection of stragglers, BMC Models that don’t fall into any of the above categories.








Morris Minor 1000
Conversions
Morris Minor 1000
Conversions
Austin A35
Conversions.
Austin A40
Conversions.
No’s 4 & 5 Touring
Conversion 1966 (again)