Chris Isaacs race cars

Unique vision - innovative design - quality fabrication

Here at CIRC it's not all drag racing... we have performed fabrication and setup work on a number of successful circuit cars, and this Morris Minor'company car' was  an ongoing evenings and weekends project for around 5 years.  Initial testing was carried out during July and August 2012, whilst 2013 saw the car's race debut competing in the Classic Sports Car Club's Special Saloons series. 
The initial two race meetings (at Brands Hatch and Cadwell Park) saw an encouraging start to the Minor's race career, qualifying in the top third of the grid at both races and coming away with a 2nd in class trophy at each venue.  An ongoing development programme is under way, to edge closer to the front of the grid.

(Photo courtesy Peter Still)
The Morris features a Jeff Bull 383ci small-block Chevy putting out around 430hp, a Tremec 5 speed gearbox, 9" Ford rear with lower A-frame and twin upper links, and a CIRC designed and constructed double A-arm front suspension with our own  fabricated uprights.
This photo was taken at a test day at Brands Hatch, where we found out a couple of things...
100mph feels a lot faster when you are going around a corner.
Compared to good old American muscle power, most circuit cars are not very fast in a straight line!  (hee hee)

Front camber adjustments,
Brands Hatch.


In the pits,
Prescott hillclimb.

On the startline at Prescott.



As purchased.  For those of you who think that colour looks familiar - yes, this is a genuine ex-Police car, and once the headlining was removed it revealed the little metal patches welded in place in the centre of the roof to cover over the mounting holes for the blue light.

The Morris was originally being built for another race series, the BARC South-East's QMN Saloon championship.  This series features several different classes on-track at the same time, with the rules for class 'A' being very similar to the late lamented Thundersaloon championship rules - you can't have a spaceframe chassis, otherwise do pretty much what you like.  As such, the Morris had to be a monocoque floorpan car, which dictated much of the initial sesign criteria.
Following the design work, carried out on both the drawing board and in CAD programs,  the cutting began.  The rear chassis rails were cut out above the 9" Ford axle to allow the axle to sit up much further into the car.  New frame rail sections were then fabricated out of cold-rolled steel sheet, and 4-link boxes fabricated and fitted. 
The right-hand photo shows our dummy small-block in place, and shows just how far back the engine was positioned for optimum weight spread.

The new diff cover, propshaft tunnel, and rear floorpans are in place here.  Subframe connectors have been fabricated and welded in from the front of the 4-link boxes to the new, custom front chassis rails which are the next addition to the structure.

The left-hand photo shows the new chassis rail in place from the subframe connectors to the footwell.  These rails are fabricated from steel sheet with internal bracing at critical stress points.  The right-hand photo shows how a folded section of steel sheet links the new rails to the original sill boxes, creating in effect a chassis of main rails, outriggers and sill bars, but in a monocoque body structure to comply with the rules the car was built for.  Also here is seen the lower mounting plate for the A-post roll cage tube.

The cutesy -shaped panel above the axle in the left-hand pic is the original Minor floor section, and this photo shows just how far it was moved up to get the required ground-hugging stance.  The old, rusty wheelwell is already removed here, and the right-hand photo shows the new replacement spot-welded into position.

The roll cage structure well under way here.


One front chassis leg under
This is the inside face...

...And the spot-welds visible on it's surface are for the internal bracing which triangulates the chassis box and transfers loads to the rest of the bodyshell.

This shows the chassis rail in position, before the outer sheet steel skin is welded into place.

The completed front chassis rail with outer skin attached, and front suspension being fabricated on the jig.  The geometry for this suspension was developed on our CAD program, and features custom CIRC-fabricated uprights.

The custom fabricated pedal box, using twin brake cylinders and a balance bar plus a hydraulic clutch.  This assembly had to be made, fitted and welded into place before the firewall was put in, and was a bit of a 'ship in a bottle' job!

The firewall is coming on well in these photos.  Note how, in the RH pic, the car has had to be 'tubbed' at the front to clear the front tyres on full steering lock.

Firewall completed, and suspension reassembled with brakes installed.  The rotors are 323mm diameter, 30mm thick vented, with Wilwood 4-pot calipers.  Also clearly visible in these pics is the tubular front bulkhead which ties the two main frame rails together top and bottom plus mounts the steering rack.  This bulkhead bolts onto the front of the main rails, and is taken off whenever it is necessary to remove the engine.

As the CIRC Morris is still a monocoque car, the transmission tunnel was fabricated from 18swg steel and welded in.  An important part of the car's intended appearance was the preservation of the original dashboard.

Bolting on the wheels shows just how wide the Morris is going to be - nearly 7" per side wider than standard!

The left-hand photo shows the fabricated aluminium rear bulkhead, bead-rolled to complement the factory style pressings.  The other photos above show the car having its underfloor welding completed - these pics clearly show the fabricated monocoque front chassis sections which comply with the 'no tube frame' rules the car was being built to.

Stainless 1.875" OD headers under construction.

Making the patterns for the fibreglass wings.  We roughed out the shape with steel sheet and parts of the original Morris arches, before smothering the whole lot with plenty of filler to get the required shape.  Although this technique may seem somewhat crude, it is actually very versatile as it gives a lot of freedom for tweaks and modifications as the shape is being built up.

Once the patterns were filled, primed and painted, moulds were taken and lightweight fibreglass panels made for us by Street Eliminator racer Steve 'Splinter' Nash.  The quality of the finished panels, as shown by this front wing, are so good that we don't need to paint them - they will be left in the white gelcoat to match the intended white paint job.

The pattern for the front air dam was made in the same way.  The use of 1/2" thick marine plywood for the front splitter element is in fact a common choice of budget-minded circuit racers - its stiffness-to-weight ratio is excellent, it is easily worked, and if you damage it you can purchase your replacement raw material from any DIY store for £10 or so!

The left-hand photo shows the fibreglass doors from well known Morris parts supplier Bull Motif.  These are actually pre-production prototypes which they kindly released to us.  The other photos show the radiator, fan and oil cooler setup being mounted.  The air dam pieces have now been produced in fibreglass.

The patterns for the running boards and front wing supports are under construction here.  Note how, on the rear arches, there is a 'scalloped' section at the front which sweeps up and over the arch, and which is fed air by the upswept rear section of the running board.  All this is to try to utilize the fairly large frontal area of these rear wings to produce a bit of downforce as they push through the air.
Next, it was off to Motorsport Repairs, where Jim Salvin worked his magic with the body and paint...

Now resplendent in white, it was time for the car's final fit-up.


Most of the removable components were powder-coated in satin black.  The silver sheeting on the firewall is an adhesive backed heat-reflective material, which has proven very effective in keeping engine and exhaust heat from permeating into the cockpit area.


The clutch, shown in the LH photo, is a RAM twin-plate unit of 7.25" diameter using cera-metallic discs, this has its own flywheel of the same size and the whole lot bolts to the back of a flexplate which is only there to provide a ring gear for the starter.  The engine revs very quickly with this small clutch, and the setup has proved very effective and reliable.


Nearly ready!  the extensive ductwork in the RH photo takes cool outside air from an intake cut into the front of the bonnet, and feeds it to the carburetor.

The Morris' first proper race meeting - Brands Hatch, May 2013, and I managed to blag a pit space next to the legendary ex-Gerry Marshall Baby Bertha Vauxhall, a car I have loved ever since seeing it at the Motor Show as a boy in the mid-70's.

Qualified a respectable 6th out of 18 entries, challenged for 5th in both the weekend's races but ended up settling for 7th and 6th overall - a decent result first time out.