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Tomcat tails.

Episode 1. The dawn of chaos.

So there I was, sitting in the office, minding my own business, when along comes this idea which totally changes my life. Again. Oh dear.
The reason for this was the All Wheel Drive Club web site and pictures of Comp Safari events. These seemed to involve people propelling themselves through rally stages at ridiculous speeds in home built specials made out of range rovers.
On closer inspection, the rally stages appear to have obstacles that no rally car could ever hope to challenge without leaving it waving its little feet in the air in total submission. There were ditches to cross. There were jumps (note: not yumps, these buggers needed access ladders and altitude breathing apparatus). There were what appeared to be bogs. This looked like a proper challenge, worthy of my unique talents and stupidity.
So, the decision was made to sell the SD1 racer and abandon my circuit racing plans (that’s another storey) and decide on what sort of vehicle to campaign.
First choice was whether to build one or buy a second hand one. Building one would mean spending at least three months working flat out (which never happens) and spending considerably more money than would be needed for a race proven finished article. Decent second hand racers go for as little as £3000, for twice that you get a really good one but the real benefit is once purchased I can immediately go out and try to injure myself.
The choice was obvious.
So having decided to build one (!) the choice was what exactly to build.
There are many classes within each club and indeed many clubs with whom to go playing with. Having read up as much as possible from club web sites and car manufacturers, I decided to get a flavour of the real thing and visited Charley who was doing a race in north Wales with the Northern Off Road Club. The range of vehicles (and engineering ability) was rather wider than I was expecting, there were basically modified road vehicles such as Land Rover 90’s running next to single seater double wishboned specials. Hmmmm. Time to ask a few people their opinions and experience. Seemed like a good idea, but of course these people have already proved their sanity by doing this sport. So predictably I got a fairly confused picture, most comments based on the fact that Land rover parts are shit/excellent (delete as applicable) depending on whether the owner actually had a Landy or not. One thing I did notice was there were a lot of range rover based Tomcats and similar.
Right then, a trawl through suppliers web sites showed that, although there are many suppliers of bits of race car, there were relatively few who could do all a race car. One of the nicest ones is of course a Bowler, unfortunately I can’t get a mortgage on a car so more down to earth options were sought. Tomcat Motorsport appeared to offer all the bits (although all as options at extra cost) and had a good range of vehicles so I went to see them. They were just moving from the shed next door so there was a certain degree of chaos, however they did have several cars part way through build up and a rather fetching white 100 ready for shipping to the customer in eastern Europe somewhere.
Steve (chief waffler) was very friendly as he gently coaxed large quantities of money off me. I began to become aware that I had bought a Tomcat 100, with all the bodywork (frog green fibre glass) and suspension mods, I don’t think there was a single option I didn’t fall for, I even bought the tyres there!
The spec was based on the range rover chassis, which is trimmed of unnecessary carbuncles and adorned with a space frame which includes some roll over protection. The rear axle is converted to use the same set up as the front, with two ‘hockey stick’ trailing arms and a panhard rod. This gives it better location and gets rid of the central ‘A’ frame which works very well on the road car but I am told is not so good for high speed off roading, admittedly I was told this by the man trying to sell it to me. The engine is moved rearwards (enough to swap the prop shafts round) and the radiator situated at the back in order to reduce the polar moment and get the centre of gravity nearer the middle. I opted for the traditional Rover V8 engine which although rather outdated now is relatively affordable (and a had a few spare engines left over from my SD1 exploits), this would drive through the ZF 4HP22 four speed auto box (auto means I can concentrate on driving rather than cog swapping). The interior is made of ally sheet and sports two Tomcat bucket seats with multi point seat belts. All I needed was a donor.
The idea was that the donor would provide the chassis, axles, two radius arms, steering system, brake system, pedal box, engine, gearbox, props, fuel tank, radiator, lights, windscreen wipers, dash unit, some of the electrical system, washer jet system, battery, wheels. That way I would be just putting a new body on a complete car and so can keep its identity thus keeping the paperwork simple.
Some time previously I had bought a Range Rover Vogue which came complete with a spare rotted three door car which had the worlds worst diesel conversion (Ford York 6 cylinder, yes six cylinder) which blew flames out of the intake on start up, earthed through the brake pipes and was flat out at 35mph. Seemed ideal as a starting point for the tomcat! So, myself and Frank (chief aficionado of the Deranged Off Roaders Club) set about ripping the unwanted parts off this rabidly depreciating classic. Luckily this was quite easy (well, initially), once the roof was unbolted most of the rest of the body work fell apart due to corrosion, I pulled the drivers door straight off by hand, complete with ‘A’ pillar!
The engine and manual gearbox were ‘carefully’ removed with an axe (I would not be using those, oddly enough) and then the chassis was inspected. When inspecting a Range Rover chassis, its not a matter of ‘is there rust’, oh no, it’s a matter of ‘how bad is it’. In this case it was bad, checking it with a hammer (I like hammers, the tool of choice) revealed several rust canyons at the rear half. Thus, with a heavy heart, the heap was declared unfit for animal (Tomcat) consumption. But the axles were ok and so were the radius arms and a panhard rod which made it worth all the hard work in the rain!
So, now I have no donor, but I do have my daily transport Vogue, I start to stare at its fearful body with axe and hammer in hand, its howls of terror unheeded……
The Vogue is a much better proposition, it has power steering and the right engine and gearbox. So its time to start cutting up a perfectly roadworthy car. I get a perverse enjoyment out of this sort of thing.
Whilst all this fannying about is going on, Tomcat are building the space frame on a jig and getting the body panels made in a rather fetching vile green. This gives me a date by which I have to have the chassis ready for them to nail the cage onto. Its good to have deadlines, I suppose.

Episode 2. Convergent complex events.

I still have to use the Vogue. Apart from being my daily transport it also has to collect the space frame and other bits from Tomcats lair on the back of Dave’s trailer (you just cant do this sort of thing without a good network of mates, preferably mates with trailers). So initial striping for inspection has to be minor! A good, relatively minor, way of gaining access to suspect parts is to rip the load bed out. Guess what, the vogue had rotted away by the cross member! Bollox.
Now, I could of course weld up the holes, but a few measurements showed that the chassis was twisted and the front curled up slightly. This indicated it had received more than one collision in its life and went some way to explaining why it had a tendency to turn left.
This revelation coincided with me being convinced that what I really needed was the later fine spline diffs, not sure why, but I needed them, apparently. From this point, it was only another (relatively) minor increase in cost to have a rolling chassis off a late Disco. Its this sort of thought process that causes the cost to slowly increase, usually until its double the original worst case budget! It is absolutely vital to discuss project changes with someone who will tell you when you are being stupid, or at least question the decision to abandon plan B and adopt plan C. But no one was around at the time and the human mind has a great capacity for justifying its own decisions to itself, despite clear evidence.
So I bought this rolling chassis. Tomcat set about the rear axle with various torture instruments and stuck it in their jig to fit the suspension mods on, whilst I set about the chassis with smaller (but perfectly formed) torture devices relieving it of burdensome bracketry and most of the cross members (only the front one is original). Looking back on it, perhaps I should have checked over the fence for children’s parties before sending loads of angle grinder fireworks their way, oops.
Job done and its off to Tomcat to deliver the bald chassis and collect bits of axle, for some reason I thought they would reassemble the rear axle (having stripped it to weld it) but I was presented with various parts and a sturdy cardboard box. Well, I wanted to change the bearings anyway. I also collected the smaller parts of body work.
When I had reassembled the axle, I eventually noticed that the dif had a three bolt input flange, all my propshafts had the usual four bolt arrangement so it was time to change it. To do this you insert the appropriate service tool (a bolt with a broken drill bit on the end) in the spigot and wind in until the central plug simply pops out. Or, as in this case, until the bolt shears off. Arse. Various methods were used to convince the damn thing to come off, such as heat, hammers, stilsons, bizarre puller arrangements, all without putting undue stress on the input shaft bearing, honnest. In the end I sliced down each side of the flange collar with my trusty angel grinder and set about the thing with a precision axe, only when it was out was it apparent that it was actually glued in.
Mean while back at the ranch, Tomcat have jigged and welded the space frame to the chassis and finished the body mouldings.
Off I go again in the increasingly lighter (don’t need that bit, rip) Vogue (I only refer to it as the Vogue because I cant be arsed typing Range Rover every time) with the trailer. The chassis and frame looks splendid as it is fork lifted onto the trailer (I briefly wonder how I am going to lift it off) and the large body panels taped onto it. At this point I really should have noticed that the cab roof doesn’t fit so well on one side and that the back body is a slightly different shape to the frame it sits on. But I am preoccupied making sure the load is secure and that I have all the bits that I think I have paid for, including five Amazon tyres which play a comedy role later.
Driving back with the space frame dressed in the basic bodywork filled me with some pride, the collection of bits looked like it was going to become a real car at last, and quite a mad one at that. In one traffic jam I remember a bloke in an open top MGB saying to me ‘looks like you weekends going to be busy’ whilst grinning. He was bloody right though.
Evidently my rumbling V8 (broken back silencer after an off road fun day) alerted some of my chums to my return, and after reversing the trailer down the narrow alley that leads to the workshop in a manner resembling a drunken Python with arthritis, I was greeted by Pat, Ron and Jim who felt it was that time of the day when some pointing and standing around was needed. I mercilessly pressed them into helping man handle the chassis into the workshop. This can be done with four people relatively pain free at this stage as it is still light (that’s light in the Land Rover sense). The bare Disco chassis weighed about 110Kg on to which was plonked about 140Kg of space frame.
Weight is, of course, bloody important to a proper racing car, but also its important to this one. Now, starting with a Range Rover means that light weight is never going to mean the same as it does to a Caterham owner, but still, the whole car is made out of many components and so each one should be optimised. Well, optimised as far as I can afford anyway.
A quick check (using a scrap of paper, a tape measure, some bathroom scales and an EWAG system) revealed that the CoG should be about six inches in front of centre thus putting about 50Kg more on the front axle. Total weight was calculated at 1300Kg, allow 100kg for being wrong and forgetting just how many bolts I need and we should be in the right ball pit. That makes it a light weight for that sort of thing!
The main bits that contribute to this are the engine (160kg with ancillaries and exhaust manifolds), transmission (about 160kg with transfer box and brake), rear axle (110kg all up), front axle (130kg which hurts when dropped on foot, I discovered), then the wheels & tyres (30kg each), radius arms (10kg each, lightened ones weigh 0.5kg less each), radiator (13kg), water (12kg approx, lots of pipe work remember), fuel tank (10kg), wiring (10kg) and battery (10kg). A set of springs and dampers in total gave 60kg, the seats and belts contributed 30kg and the complete steering system was about 50kg. Then there was the exhaust which I guessed at 20kg (not much of it), fans, windscreen etc.
The engine would be moved back in order to improve weight distribution. The deciding factor for exactly how far back to move it was based on the scientific principal that I couldn’t be arsed making new prop shafts, thus the front one is on the back and the back is on the front leaving the engine about eight inches further back.
So now I am master of all I survey. Precisely what I survey is largely a pile of bits and a workshop. This must mean is time to do something, I put the kettle on.
First step is to decide where each bit goes. Its important at this stage to consider how each bit will do its job and how they all work together whilst remembering my design philosophy, that is 'keep it simple, easy to fix, effective and light', specifically I really did not want to add brackets where possible, instead try to bolt a part to something that was already there. Also, all weight added had to be inside the wheelbase (low polar moment to allow it to turn easily), as low as possible (low roll moment to allow faster cornering before it falls over) and put so as to get good weight distribution (to get balanced cornering and flying well from jumps).
Starting with the radiator, many chaps nail this directly to the rear bulkhead where the fresh air arrives, thus keeping it simple and effective. This seemed to easy for me so I decided to lower it which meant moving it back so the fresh air could get to it, it also meant fitting a baffle round it to stop hot air circling round to its front and reducing cooling. So that’s all four parts of the philosophy buggered in one go. Terrific.
The fuel tank is an oddity. This is an ATL racing fuel cell with foam in. The valve block allows you to hold the thing upside down and no fuel will fall out. Also the fuel in it does not slosh about much which helps to keep circuit racers steady (but makes sod all difference in a ton and a half of ballistic range rover). So, its very safe, but it needs to be put in a metal box. I made a steel tray for it to sit in that would protect it from rocks flying up and made an ally overcoat for the top and sides. All rather a snug fit and secured with lots of little bolts.
Deciding where to put the tank was not straight forward. Because it as not designed to fit in this chassis, it doesn’t. It ended up above and to the rear of the back axle, inboard of the right hand chassis rail. This allows easy filling but does mean that its difficult to find somewhere to put the spare wheel. So now there's no spare wheel.
Putting the tank to one side allows the exhaust to occupy the plot to its left and exit above the rear bumper. This avoids the problem found with exiting below the bumper where the exhaust gets flattened when the back end drags down a bank or I reverse into a parked car, errr. The alternative is to exit the exhaust in front of the rear wheel arch, but that would mean making some tight bends and thinking it through a bit, no chance.
In the gap between the radiator and the bulkhead is a nice pace to drop the battery and also a large washer bottle. The windscreen washers are the headlight jets from the rangey which blast the mud off the screen thus allowing the wipers a sporting chance without having to lift turf up on every stroke.
By the way, if you follow this rout and put the jets on the bonnet, please remember to fit them such that they don’t hit the wipers when you try to open the bonnet! Bitter voice of experience and stupidity speaking.

Episode 3. Let the bodging commence!

Right then, having faffed around for far too long working out the principals, it is now time to do some damage to the chassis. It is during the trial fitting that you find out how wrong you really were.
But first a felt the need to try my new Amazon Bastardgrabbershitflinger tyres on the rangey. A quick trip to my local tyre fitter and I had them on my vogue wheels, most chunky they looked too. Actually they are very chunky, as I discovered whilst reversing out of the fitting bay when upon applying right lock the front left fouled the under bumper spoiler thingy. Well, I say fouled, actually it ripped right through it then when I drove forward I inadvertently drove over it and it ripped the whole lot off with a clatter of fog lights. I was not at all embarrassed as I stopped and put the broken parts in the back of the car! The tyres proved slightly more skittery on the road and surprisingly well mannered. This was the Vogues last trip before the body snatchers of the garage would descend upon its terrified parts.
The chassis was put on stands ready to trial fit the axles, engine/transmission, radiator, seat (well, actually a block of wood because the Tomcat seats hadn’t turned up yet, wrong sort of leaves on the production line or something…), steering column/ wheel, gubbins and bobbins.
Trial fitting the axles raised some issues. Firstly, of the two radius arms supplied, one was bent and the other was cracked! So I used the two from the first donor car. It was at this point that I discovered that early Range rovers have thinner radius arms! After some swearing I made some 4mm thick spacers and fitted them anyway. The spigot at the chassis end is also thinner so I had to make some sleeves so it would fit my nice new bushes. Oh, and they have a different thread. But apart from that they are identical to later ones.
The panhard rods are a bit tricky to fit unless you get the axles in just the right position (about normal ride height) because of the arc the axle moves through tends to twist the rod.
With that lot now on I could move the axles through their full movement and check for clearance quite easily. This highlighted that the front diff is coincident with the engine oil filter on full bump. To resolve this I purchased a remote filter pump base and ran hoses from the pump base to the front grill where I made a simple cross bar with the oil filter and cooler. This makes changing the oil filter rather easy as a bonus.
By the way, I got some of the parts for this from an Autograss race stall, there is a huge quantity of simple and cheap parts for oil systems, suspension, steering, seats etc usually for sale at their race meetings, Evesham is a good one.
After this messing about it seemed that the axles will clear most of the important bits so I fitted the springs and dampers. The dampers are Fox 12” jobbies with spherical joints at each end and are very shinny, which is good. The problem with spherical joints is they wear very fast if you get them dirty, also the degree of fine control they give you is rather irrelevant for this sort of application. So when they finally go they will be replaced by bushes. You can of course purchase specially made rubber boots for them or try the old racers trick of using a party balloon with thin washers around the bolt hole.
First up after that was fitting the engine, I intended to fit the engine and transmission as one lump (it is known to be running so one less thing to worry about) and it would be easiest to get round it to fit mounts whilst there was nothing else there.
I drove the vogue up to the front of the Tomcat so I could 'simply' take the powertrain out of the vogue chassis and plonk it in the new one. What could possibly go wrong?
Well, the thing about old cars is that they have invariably been 'repaired' by brain damaged syphilitic monkeys. Each monkey knows only one way of fixing things, with some its by fitting pattern parts with a hammer, with others its patching things with broken mechano and bloody self tappers (self tappers are evil, no good will come of it). With the monkey in question it was welding, so where the gearbox bracket bolts had corroded through, the solution must have been obvious to its tiny over stressed brain, weld it on! Arse! There were many treats like that in store, such as when I wished to retrieve the ECU and wiring from under the drivers seat, only to discover that the floor had been welded to the seat base.
Luckily I have some fairly aggressive vehicular abuse tools, a selection of angle grinder paraphernalia, very big crow bars, air chisels and the such like. All good fun.
With the victims terrified heart torn out and offered into the chassis the revised engine mounts could be fitted to the engine and tacked to the chassis, then the original gearbox mounts refitted in the new location. This involves drilling the bolt holes and fitting tubes in them to prevent the chassis rails being distorted by the bolts (which would eventually result in them working loose or possibly breaking). The trick to this is drilling a bolt sized hole the gearbox side of the rail and an enlarged hole on the outer side, the strengthening tube has a flange welded on one end and is fitted into the hole, slot the inner hole with a small cutting disk and you can put two dobs of weld onto the tube, the flange end is welded to the outer side.
The Tomcat engine mount kit has very little fore/aft stiffness so I put a gusset plate in.
At this stage I noticed that the transmission brake was fouling the drivers seat belt mount which is welded to a piece of box section welded to the chassis rails. It turns out there are many types of transmission brake, mine is the large one. I cut the offending mount off and fabricated a new one further back.
I pushed the remains of the Vogue into the yard where I would keep it until the Tomcat is rolling. This is a lesson I have learned the hard way, when using a donor car, keep the thing about until you have finished building the project, its amazing how many small bits and bobs you need from it.
With the engine and box installed, it is now time to start putting things in around it.
I supplied Tomcat with a pedal box on an exchange basis. They weld in a simple frame and weld the pedal box directly to it. It is lightly unfortunate then that the standard brake servo fouls the damper top mount! The pedal box is now about an inch further back and tilted slightly to give good clearance. Of course, if you use later Discovery servo and master then there is no problem as it is about four inches shorter in total!
With all the main oily bits nailed on I turned my attention to the 'bodywork'. The interior is ally sheet which had been laser cut and pre shaped. Unfortunately it must have been pre-shaped round a different car because quite a few folds were in the wrong place, so I had to flatten the sheets and re-bend them. Whilst doing this I took the opportunity to make the foot-well narrower to give me clearance to the right hand exhaust manifold bolts which would otherwise require the engine to be removed to get at.
It was at this stage that I found out that the transmission brake fouls the seat mountings (there are many different sizes of transmission brake, I had the big one!) so the seat support rails were cut out and new ones put in with the lap belt mount fitted behind it. The transmission tunnel had to be reworked to put pockets in in order to go round all the components and still leave room to put the seat bolts in.
The interior starts to take shape, the range rover steering column goes in without complaint. The transmission tunnel is used to support the coolant pipes, fuel pipes, cables and brake pipes as well as support the gear selector and hand brake leaver. I made this from sheet ally with the sides bent in two planes so it was rigid and did not require a support frame (its strong enough for me to stand on) and I incorporated an inspection hatch to make transmission fiddling easier.
I held the arch liners up on boxes whilst I made brackets for them. All the body panels, including the arch liners, have to be cut to fit. Every car is slightly different and the method used to mount the panels is entirely down to the builder. This degree of freedom inevitably leads to excessive thought and overly complicated solutions! it is vital to discus any designs with chums who will tell you when you are being stupid. Everything has to be positioned not only so it will work, but also so that it can be accessed easily for servicing or repair.
I actually took time to weigh the whole interior and exterior panel work, weighed in at about 50kg in total, which is fairly impressive.
The front wing goes on, I decide to space the rear edge out about an inch so that it fits without cutting the rear edge off and loosing its strength. The wing needed a little further support, but I didn't want to put a heavy metal frame in (because of weight and also I want the panels to flex when I hit the scenery rather than break). The solution is in careful mounting of the inner wing to give it stiffness and some flexibility.
With all the body panels on it became apparent that I had to do something about the lights! Other than a slightly bug eyed look it was quite nice to reach this stage, although there is still lots of work still to be done at least it looks like a car finally. Time for a cup of tea!
With a plethora of small jobs still to do it was time for a shake down run at Avon Dassett. The first drive was amazing, the suspension soaked up huge bumps with ease and the barely silenced engine sounded fantastic. I did find the pedal position a bit uncomfortable so once back at base I cut them up and started again, other than that the only problem on the day was the fuel pump passing out after several hours of abuse so I slipped a new one in as a special treat.
Now to try a bit of racing...

 
 
 
 
 
 
 
 
 
 
 
 
 

©Ralph Hosier