JoMoRo and the BL / Shaw Rover

Looking through British Leyland´s press release on the Bill Shaw entered, Roy Pierpoint conducted Rover 3500 whetted our curiosity as to how the car had been turned from a well thrashed rallycross nail into the shiny red beast ready for a round of the Hepolite Glacier championship at Mallory Park a few weeks ago. The car didn´t win on that occasion or at Brands Hatch on Sunday, though the Rover did go quickly before succumbing to gearbox troubles.

To find out about this brave project to inject variety into saloon car racing we went along to see the proprietors of JoMoRo racing at Westhill Service Station, Brookwood, Surrey, who were entrusted with the task of preparing the Rover from scratch. Only the engine was prepared outside, simplifying maintenance when the car is required to appear at a number of meetings in quick succession. Plans for this car are to make sure it appears in the maximum number of good clubbies to sort out the feasibility of producing a Group 2 version: a second car, to a different specification, may well be produced in time for the Tour de France.

The first point to sort out is just who are JoMoRo racing? Well the name is made up from the surnames of ex-Alan Mann mechanics Jimmy MOrgan and Jimmy ROse. It may not the most inspiring name for a business but these two gentlemen have a lot of experience behind them and Those Who Know among the Ford fraternity speak very highly of the pair. Morgan worked for John Coombs before joining Mann to work on the highly successful saloons and Chitty Chitty Bang Bang. The latter project was very enjoyable for Morgan as the team worked merely from the film studio´s undetailed drawings and so were able to make up virtually everything as they went along. Remember the torsion bar suspension on the rear of Mann´s Group 5 Escorts? Apparently it started life when they seized on a poor Morris Minor outside the works, measured everything up, found it would all fit reasonably well and proceeded to a scrap yard to get the bars: BL strikes again! Shortly before Mann disbanded his racing shop at Byfleet, Morgan left to pursue his own interests in Britain, including the auto/rallycross MiniFord, the Springbok series winning Grand Bahamas Racing Lola 70 of Mike De Udy and, the Rover project plus some work on Ecurie Evergreen´s McLaren M8C for Chris Craft.

The other half, Jimmy Rose, started off at Lotus in the Cheshurst days and stayed there for eight years working on the Lotus 27 and the infamous 30, among other things. Then he also went to Mann meeting up with the other Jimmy and working on GT projects including the ill-starred Honker Can-Am machine and the equally fated F3L. Before the sleek DFV prototype was finished, Rose had headed for the USA and Holman and Moody.

After 18 months in the States he came away impressed by Can- and Trans-Am preparation standards but distinctly unmoved by the big NASCAR stockers with their flabbily located front suspensions. Rose spent much of his time at the drawing board and his talents in this direction have helped enormously with the Rover: a look at the mound of drawings the Jimmys keep shows that the MiniFord (which is „just my hobby“, according to Morgan) and a perfect little monocoque for a single seater have also come from the Rose pen.

Not long after he returned to England, Rose became involved in the Rover idea, working from Roy Pierpoint´s family business premises at Hersham in Surrey, where Morgan joined him on the initial chassis work. Still without premises of their own, the two went to work for the best part of a fortnight at Broadspeed while the Rover´s plumbing was being attended to. By Easter time things were really hectic with Rose putting in a couple of days work on the Shaw Camaro, while Morgan went to Trojan and the Craft/Cadanet M8C and tried to make it work at Thruxton. When he got to the circuit on Monday he found Rose with the Camaro, as Shaw´s mechanics had let him down on Sunday! Morgan still has some involvement with the Ford powered McLaren (which should be ideal for the Nordic Cup series) but naturally enough he and Rose are keen to get on with the Rover, as it´s still got plenty of scope for development.

All the same, after 20 weeks hard work the pair have turned out a pretty exciting saloon, turning the slumbering 3500 into a comparative lightweight with liberal use of alloy and glassfibre inserting 4.3 (explaination follows!) litres of Traco-Olds/Rover, fabricating a lot of new suspension parts and stopping it all with whopping great McLaren-style ventilated disc brakes! The engine is the least complicated part of the story because Mathwall Engineering took after its preparation at Cobham in Surrey. This company specialises in American V8s and they set the engine up to Traco specifications using modified pistons, Chevrolet con rods, cast alloy inlet manifolding, heads, hydraulically operated camshaft and „stroker“ crankshaft. With both the bore and stroke enlarged, capacity is 263 using an externally standard block for the all alloy engine. Bore and stroke is 3.563 in. by 3.5 in., a rough calculation shows this to be 4303 cc. Wet sump lubrication is used and a Borg and Beck triple plate clutch.

Power output is said to be 365 bhp, assuming those quadruple Webers are right in tune ad at present they seem to be well on form. The snag at Mallory Park was that all that horsepower was reaching the ground via a rather inefficient transmission set-up, the ratios in the manual 2000 box being far too widely spaced and the final drive ratio to high at 3.5:1. Mallory helped the partners enormously for the car had done only two inconclusive test sessions before its debut, so information on the effectiveness of the suspension and transmission all came on race day!

Likely changes to overcome the problems experienced at Mallory include lowering the car on its suspension a little more than the present 2 ˝ inches, which should stop the rear wheel picking up quite so readily. A wide range of final drive ratios for the Land Rover based differential is available, so they should have no further problems in this respect. A new gearbox, such as the five speed ZF, would help enormously but there seems little hope of getting one at present.

Although the basic Rover 2000/3500 front suspension system is retained, with a lever and horizontal coil spring shock absorber unit, the pair have returned to the drawing board to produce some tubular steel triangulated lower wishbones with adjustable ball type joints. These lower arms attach at a point approximately one inch higher than standard, to the benefit of the car´s roll centre.

However the trickiest job was to mount the 12 inch diameter Lockheed ventilated discs, the special hubs necessary to use the fully floating discs being designed by the partners and machined locally. At the back the standard De Dion tube had already been given the rallycross treatment with beefing strips of metal and weld in abundance, so some more weight could be saved on the tube. JoMoRo have affixed what they describe as a „light anti-roll bar“ to the tube: thick bars are just a waste of time so far as they are concerned, „all you do is pick up wheels“ says Rose. On paper the rear suspension conforms to standard specification with trailing arms, coil spring/shocker units and locating rods for the De Dion arm. However in detail there are quite a few changes: for a start those trailing arms are 1 ˝ inches longer and a fresh box section has been made up under the rear seats to locate them. Phosphor bronze bushes help the arms to do their job more precisely; in fact accurate feeding in of the suspension loads has been the most important task and it was for this reason (and a little weight saving?) that the differential´s subframe was thrown out and a box section fabricated to take its place. Both the diff and torque tube are accurately located by short steel arms. The box section under the floorpan takes both wishbone and torque tube loadings, via these tubular arms.

Shrouding the differential one finds a pair of inboard 10 inch diameter ventilated discs. Getting them there involved a lot of calculation taking into account the amounts of space needed to clear both calipers (all Lockheed) and the offset for the new hubs. On the second attempt they went in together with some thicker differential output stubs, the driveshafts were standard at the time of our visit. As is customary with racing saloons, no brake servo is fitted, but a brake balance adjusting bar is.

The rest of the bodywork is pretty sensational for men who make no pretence of being trimmers or styling experts. The bulged arches were drawn up by JoMoRo, being partially fibreglass as all four wings are made of this material, while the rest of the external panelling – bonnet, all four doors, sills, bootlid, popriveted roof and much of the interior are all made from pressed aluminium sheet.

Inside the lightening process has been covered by some pain-stakingly applied black PVC and much of the original equipment, including the wooden door trim cappings. Four seats are supplied and all of them were functional so far as I could see, so there is room for some further weight paring here in clubby events. Morgan commented dryly that they found on removing just the seats they had saved half a hundredweight and a similar figure was mentioned for the doors!

The changes to the dashboard layout are more than one would guess from a casual glance, the speedo being retained among a cluster of switches and a pair of supplementary instruments. One very neat idea is the wiring up of all the standard idiot lights within the speedometer so that they all come on simultaneously, should the oil pressure drop alarmingly.

A gleaming red and white finish and 10-inch rim Minilites certainly add to the bulbously functional lines of which the partners have every reason to be proud. They still intend to revise the front suspension geometry but apart from that and the selection of suitable transmission bits there seem to be few problems.

Dunlop 4.50/13.00 by 15 inch tyres are used, with sets for both wet und dry they are of the same type as were fitted to F1s a few seasons back when rim widths had not got to their present gargantuan proportions.

After two races the Rover project shows every sign of being a success, provided the powers that be will allow some more development work to overcome the transmission troubles. Perhaps British Leyland could take a leaf out of the Ford book and homologate such things as a decent gearbox? Such a move would presumably make it decent for a ZF or E-type box to be used in club events, although the car is already a long way from being a straightforward Rover! Much the same goes for any competitive Escort though, even in Group 2 trim. Whatever happens, I am sure we are going to see a lot more cars bearing that JoMoRo label.

U.K.  May 1970