The Story of Roger Jefferson's Supercharged Arkley MLO 410D
My first encounter with an Arkley was in 1983, when a new employee at the company I was working for turned up in one. It was based on a 1966 1098cc Austin Healey Sprite Two years later, I bought this self-same car without an MOT, from him. In no time I managed to get it 'on the road' but, disappointingly, shortly afterwards, in September 1985, the gearbox failed. The car was put away for the winter and during the following year, stripped down. It needed a lot of welding work, which included floor, inner and outer sills, 'A' posts, foot well-sides, repairs to inner and outer front and rear bulkheads, new front chassis rail and repairs to rear wheel-arches. (How it passed an MOT the year before I don’t know!) This would have been very expensive to have had done at a garage, so, I enrolled on an evening course to learn about welding and soon set about purchasing an oxyacetylene pack (D.I.Y. MIGS were not about then) so that I could get on with the work myself. However, after a lot of effort I did not seem to be getting very far and lost interest. A friend of mine had bought a ‘basket job’ Lotus Elan at the same time as I bought the Arkley, bought a new chassis and was well on the way to having a rolling chassis. I, meanwhile still had a long way to go to finish my chassis.
At about the same time as I lost interest in the Arkley, A friend told me about a 1978 ex-Rally Mini-Clubman 1275 GT which had been laid up for about 4 years and needed a small amount of work to make it roadworthy. I did it up and got it on the road within six weeks. Then I decided to race it.
So, over the next six years I raced at most of the U.K. circuits in the ‘Post Historic Touring Car Championship’, winning my class in the championship 2 years and I held 9 class lap records.
All the time I was racing the Mini, the Arkley sat next to it in the garage on four beer kegs, and every time I thought about working on the Arkley, something went wrong with the Mini. I realised that the Arkley would not get finished while I was racing.
Eventually in 1994 I decided to quit racing and concentrate on the Arkley. At this time, a neighbour's son, who was interested in welding, helped me for a while (until he found a girlfriend). The turn-around period came in 1996 when I met a chap who had worked on restoring Rover cars and he was able to assist me.
This was very fortunate because I had, at that time decided that, if the Arkley was not on four wheels by Christmas, it would 'have to go'. All the welding was finished. The car was tipped on its side and the underside prepared using a wire brush on an angle-grinder. It was then painted with two coats of Finnigans No.1 and two of black Hammerite Smooth. The rear axle and springs and front suspension were fitted. Coincidentally, that particular year produced the coldest winter on record for thirty years. It was so cold, in fact, that I actually had to build up the front suspension and spray this and other car parts, in the Utility room. The suspension was then duly bolted onto the car. We did manage to get it onto four wheels in the time I had set. It still had no engine, but at least the bodywork was well under way and the brake pipes and fuel lines were fitted at this stage.
Things still seemed to progress more slowly than I would have liked and so I set myself a timeframe for getting the body sprayed and the engine installed and running. I made up my mind that this would have to be done by the end of 1997.
During the summer of 1997, the Arkley came out of the garage for the first time in twelve years. I wheeled it outside, basically, to paint the inside of the tub. I cleaned up the inside and painted it black to match the trim.
A lot of things on the car had originally been done badly and, therefore, lots of things had to be re-done. For example, the spare-wheel mounted on the outside of the rear bodywork flapped up and down as the car was driven along. So, I welded bracing behind it, to support and reinforce it and to ensure that the wheel was firmly in place. Plates were added to mount a roll cage.
All the welding work was to ensure that the Monocoque structure was sound again. Fortunately, because the original 'Frog-eye' had a one-piece front, the front wings on a Midget did not add anything to the strength. At the back there is a chassis-member, which runs down over the rear wings to the 'spring-hanger'. So you do not really lose any strength from taking the back off. The transmission tunnel, boot floor and the bulkhead, did not have to be renewed. Just about everything else, however, even the front parts of the chassis-member, did.
The car has 'flares' on the wheel-arches so that wider wheels can be fitted and was shod with 225/60 x 13 tyres. However, these were too wide and had actually rubbed through the paint on the underside of the wheel-arches, which in turn caused rusting, which then had to be made good. I intend to fit 205/60 tyres, which are narrower and nearer to the diameter of the original tyres.
At this point, I noticed that the fibreglass rear end had been fibre-glassed over underseal onto the rear wheel arches and that this was coming away. This meant tipping the car onto its side with the weight of the suspension and axles fitted. Ingenious use of jacks and an engine hoist enabled me to do this single-handed and the old fibre glassing was removed, the underseal stripped off and the rear end re-laminated to the wheel arches. At the same time, a piece of 22mm copper pipe was formed to the shape of the scuttle and bonded onto the inside of the bonnet to keep it in the correct shape.
The next stage was to fit the engine and gearbox. You may recall that earlier, three months in fact after the car was purchased, the gearbox had 'packed up'. Well, fortunately, I had a spare one (which had been wrapped up in a plastic bin-bag for about 14 years) and decided to use this as a replacement. Unfortunately, however, it was from an earlier model (smooth case) and, according to the Instruction manual, could not be fitted to a later model.
I decided to try to prove the Manual wrong. Because I eventually want to put in a close-ration gearbox and a bigger engine, I did not want to buy another gearbox. So I looked at the clutch-release mechanism and found that this was different but that, by re-drilling the casting of the old box, I could fit it into the re-conditioned one.
Chuffed with this piece of work, the engine, gearbox and prop shaft were installed in the car. I then noticed that the fan belt was not in line with the water pump pulley, which probably explained why the original crankshaft pulley disintegrated. Putting a washer between the alternator and the mounting lug on the water pump solved the alignment problem but it was now obvious that the alternator was not square to the belt! Bending the rear mounting brought things into line.
I now concentrated on getting the body shell and doors ready for spraying. The bonnet would be left until later to avoid damage and to allow for modifications to fixings, etc. The body-shell and doors were duly sprayed 'Tartan Red' (Oct. 1997) and the doors taken inside for safe keeping until required. My next target was to have the engine running by the end of the year. The heater and a few other bits, including a few wires (to enable the engine to be run by filling the float chambers with petrol) were fitted. Could things be so straightforward? The simple answer is no. It turned about half a turn and then stopped. I thought it might be the starter-motor which was at fault - it was not. I then had to take out the engine and the gearbox again. The back of the clutch, which is a hexagonal shape, had fitted into the gearbox but, as soon as it tried to turn, the corners of the clutch were hitting on the bell housing.
Now I knew why the manual had suggested that gearbox could not be used with that engine! They had not reckoned with my determination, however!! At this point, it was New Year's Eve 1997. I decided, therefore, to forget about it for a short while and go off for a few beers. A few days later, having mulled over the problem, I decided that there were three choices open to me: 1.Fit a smaller clutch, 2. Fit another gearbox, or 3. Get out my 'angle-grinder’. The third option was chosen and I then proceeded to grind off some of the metal from the inside of the gearbox. A few days later it was running. When the engine did run, it had good oil pressure but removing the oil filler cap revealed another problem - lack of oil to the rockers. The rockers were removed and checked and appeared to be O.K. I decided that there was probably a build up of sludge in the oil way to the head. As I was eventually going to replace the engine anyway, I thought I would take a chance and run it for a longer period when the radiator was fitted - in the hope the blockage would clear when the engine got hot.
The radiator was duly fitted and filled and the engine left running. (At this stage the choke was operated by 'mole grips' on the carburettor spindle; the throttle pedal was a piece of welding rod fitted to the throttle linkage; the ignition key was simply two wires touching together). As the engine got hotter, oil started to dribble out of first one rocker, then another and then another, until normal service was resumed.
The next task was to fit the doors. The doors had to be fitted before the windscreen to enable it to be aligned with the angle of the quarter lights. Therefore, as I needed not only locks but also several other parts, Stoneleigh could not have come at a more opportune moment. (Largest MG Autojumble in Europe held at N.A.C. every Feb).
Soon after returning from Stoneleigh with the new door locks, glass seals etc., the doors were assembled and fitted to the car.
The windscreen had been left in the garage. Unfortunately, when I had been cutting and grinding, I had managed to get lots of little bits of metal 'melted' into the surface of the windscreen. I tried to get some of these filings out, then bought a polishing kit and spent a whole day polishing up the screen. Afterwards, I decided to polish up the aluminium frame, which was being loosely held, with a bit of cloth to protect it, in my 'Work-mate'. After polishing, I decided to put a new rubber in the bottom to seal it to the bulkhead. I then decided that I needed something to help ease the rubber in. So, I walked across to the other side of the garage to get a screwdriver and then, suddenly, there was an almighty crash.
The windscreen that I had been working on all day, lay on the floor shattered. There was just one thing to be done, and I did it. I bought another windscreen and had it fitted by someone else.
Well, when the original owner, whose job had been wiring up racks in communications, decided to re-wire the car, he had fitted 90% of the wiring in the same colour, with a lot of little terminal blocks that gave no indication as to where they led.
So, as the car is a 'hybrid' - (it is about a foot shorter than a Midget, and the rear lights are different - it should have had positive earth for the dynamo, but this had been changed to a negative earth, using an alternator), I realised that any new 'wiring-loom' I bought would be wrong. Also the windscreen washers were manual, the horn button (on the steering column) was disintegrating, there was no headlamp flasher or single wipe facility etc. More food for thought! Being a 'Mini' man, I decided to use one of a couple of Mini wiring harnesses that I had kept, and modify it so that I could use it on the Arkley.
So, I laid the Mini harness in and, without a lot of modification managed to get it to fit. The steering column was modified to take a 'Mini's twin stalks. A new dashboard was added and the result was that I now had the horn, headlight-flasher, intermittent wipers and washers, on the end of a twin steering-column-stalk. A reversing light was added and the rear screen heater wire used for a fog light connection. The wires for the front lights were left unterminated in the engine compartment, until the bonnet was fitted.
The original car is a 1966 model, but the rear Arkley bodywork was based on a 1967 type.
The original owner had never bought another hood and consequently, in bad weather, had to prop up the rear of the hood with a piece of wood. I obtained a late hood frame and then adapted the rear inner wing panels to take it. I went out and looked at someone else's Midget so that I could decide where to put the mounting holes. Then I noted that the hood frame was damaged. The middle hoop was lower than the front and back ones. I therefore checked out another Midget and bent the frame back into shape. A new hood was purchased, which did not fit properly. I decided to go over to take a look at a friend’s car and measure it. My hood frame was 1" higher and the cockpit 3/4" longer than my friend's car. This means that I have now bought a new hood which needs 2" let in the back to allow it to fit. I now had to make up some adaptor-plates to lower the hood to the correct height, the hood should then line up with the windows. This done, the car was then taken to a local trimmers to have an extension added to the back to meet the bodywork.
Luckily, there is a chap in my village who can put in the extra section required.
The bonnet was refitted, with the copper tube bonded in place, it was now the same profile as the scuttle, but it was not at the same height. Brackets were fabricated and bolted to the bulkhead to take bonnet pins to locate the bonnet, and rubber tubing was fitted over the pins to set the bonnet at the right height. Unfortunately, the bonnet could not be opened by lifting on one side as had been possible to do before, as it jammed on the pins. Another trip to an Autojumble provided a Triumph Herald bonnet handle which was mounted centrally on the bonnet.
Aluminium 'top-hat' sections were made and riveted to the foot well sides to guide the bonnet and ensure it lined up with the pins. With the removal of the original Sprite front, there was now no radiator shroud or heater intake. The heater had been left to suck in air from under the bonnet. An aluminium radiator shroud was made and fitted (I was lucky enough to be working at a company which had a workshop I could use at lunchtimes) and a new Sprite air intake panel was purchased and 'butchered' to make a bracket that could be fitted on to the front wheel arch and a matching hole cut in the side of the bonnet. I noticed that when I closed the bonnet, it did not line up with the pins. This was because when it was opened it distorted under its own weight and sagged, effectively making it shorter.. More reinforcement was added in the nose and a tube was bonded in the front to take the light wiring harness from one side to the other.
The original Arkley grill consisted of a piece of expanded metal bonded in the front. I removed this and made up a new grill by taking out the slats from a Mini grill, shortening them to suit and mounting them on new brackets that could be screwed to the front of the radiator shroud.
Originally, the indicators on the Arkley were in a recess under the headlight. They were 6W repeater lights off the side of a car. Such lights are not actually legal nowadays, also they are not really very visible.
So, it seemed a good idea to try to find an alternative but, as I could not find anything in a pod to match the headlights, I got some Lucas indicators (which are nowadays used on Motorbikes and some cars.
As the front of the bonnet is angled on each side, mounting the indicators directly to the body meant they would be angled forward, so brackets were riveted and bonded to the inside of the bonnet and holes drilled through the bonnet, so that the stalks of the indicator could be mounted square to the car and pass through the hole and be mounted on the brackets. The original indicator recesses were filled. The bonnet was now removed and taken to be painted. I now decided to concentrate on the interior. Access to the boot is from inside the car and the hole was filled by just pushing the original bulkhead panel into place.
I riveted angle between the wheel arches to form a rectangular hole, to which a lockable lid can be fitted. I then made shaped aluminium panels to fill the gaps at the side.
Some of the original carpets (rear shelf, transmission tunnel, under seat) were in reasonable condition and refitted. The previous owner had put carpet on all the interior trim. The foot well inner panels were in good condition and refitted, as were the sill panels. The outer foot well panels were badly worn and one was melted, where someone had previously done some welding. I made new panels - the same height as the sill panels - and covered them in carpet.
The painted bonnet, lights and indicators were then fitted and the wiring for the latter wired up.
A self-adhesive number-plate was stuck to the front of the bonnet and racing mirrors fitted to the wings.
A new 2-part sliding bonnet stay was made from aluminium rod, to replace the piece of washing line that had been used by the previous owner.
The car was then trailered to the 'trimmers' to have the hood modified and fitted and some vinyl covered trim panels made for the rear wheel arches, doors and the top half of the outer foot well sides.
Interior door handles and window-winders were then fitted.
New foot well carpets were purchased and fitted.
When purchased, the car had a low-back bucket seat for the driver, the original (very tatty) passenger seat, and was fitted with 3-point harnesses. Replacement seats are about £600 and I am loath to spend this sort of money on seats. Instead, I would prefer to spend it on tuning bits, in the future.
A pair of Cobra high-back bucket seats, with harness slots, were, therefore, bought instead for £140 and bolted directly to the floor. The original harnesses are very worn and I replaced them with a new pair of ‘LUKES’.
The car was now ready for the M.O.T.
As I had purchased a new speedo, I trailered the car to the M.O.T. station so as to get an M.O.T. certificate with zero miles on it!
The car passed it’s M.O.T. on the 25th of March 1999.
Like an idiot, I put the car on the road on the first of April.
I got up early and drove a few miles up the road to check everything was O.K. before setting off for work.
With 12 miles on the clock it started to misfire, then lost power and stopped.
Luckily my insurance included breakdown recovery, so I duly phoned them up.
Now my cousin, who has the same initial as me works for a local breakdown service, and on April 1st, gets a call from his boss to go and recover himself as he has broken down on the A14!
It was obviously an H.T. problem, so the car was taken home on the back of his truck.
The fault was traced to the rotor arm.
19/4/99 took Arkley to MGOC meeting, and noticed it was charging at 20 amps continuously.
Removed alternator and swapped regulator – settled down to below 10 amps within a minute and charging at 14 and ¼ volts.
2 months later when making the same trip, I noticed a rattle and a drop in oil pressure, so I backed off and pulled off at the next exit. It sounded like big ends. Too embarrassed to call out the recovery again, I called my wife to come and tow me home. Disaster after 275 miles.
Subsequent examination showed no 3 big end had gone, possibly caused by no 3 gudgeon pin carving big lumps out of the bore!
Although I had intended to replace the engine at some stage, I had rather hoped it would last a bit longer than this, so that I could de-bug the rest of the car. Also, I had not decided on what sort (spec) of engine to fit.
Years ago I used to run a 1098cc Morris van, the engine of which was so badly worn that my workmates used to bring their waste oil into work – I put a pint in when I left home and another pint in when I left work, and this was for a trip of 10 miles each way!
Eventually, when I had to stop twice on the way home from work and remove and clean the plugs, I decided to replace the engine.
The van had long since gone, but the old engine was still under the bench.
I stripped the engine, fitted a set of cord rings, new mains and big end shells, the Sprite camshaft and head, and even managed to find the Morris flywheel and clutch. We were back in business.
Although it had 60p.s.i. when cold, this dropped gradually to about 20 as the engine got hot, but what the hell, it was only temporary!
About 300 more miles were put on the clock without major incident.
During February 2000 I decided to buy some new tyres, the car was currently fitted with 205/60-13s on the front, and 225/60-13s on the rear, the later not giving much clearance between tyre and rear of sill.
The wheels (7 X 13 Cobra alloys) were rather tatty, so I had the insides and tyre wells grit blasted and polished the outside faces. The insides and tyre wells when then painted with engine paint to (almost) match the car.
M.O.T. time! The tester noticed some end float in the offside rear hub. Investigation showed that the outer race of the bearing was loose in the hub. I knew that I had an A30 rear axle kicking around that was once fitted to my trailer (I never throw anything away, you never know when it may come in handy!).
A hub was removed and fitted to the Arkley, and this cured the problem although I do not understand how this loose bearing resulted in end float.
A trip to the coast to visit my parents resulted in the exhaust grounding on an undulating bit of road – the exhaust consists of a L.C.B. + a length of pipe + a silencer from a Renault that happened to fit the pipe.
The pipe and silencer ran parallel to the ground. I removed the pipe to bend it, and having removed a wheel to do this, noticed that the rear tyres had still been rubbing on the wheel arches, even though there is ¾ of an inch clearance when the car is static. I assume that with the sticky wide tyres, the springs are twisting under hard cornering.
Quick call to Peter May Engineering for panhard rod.
Now this should be simple to fit, drill 3 holes in the boot floor and weld a tube to the rear suspension-wrong! It fouled the petrol tank. Phone Peter May, Have I got an original tank? No. The flange on the pattern tank is about 1 inch all round, where as on the original it is generally much narrower, just being wider near the mounting points.
Off with the tank, modify, re-fit, fit panhard rod.
We now have 921 miles on the clock.
After a few weeks, I jacked up the back to check every thing was O.K. and noticed play in the nearside wheel bearing. Both wheel bearings were replaced, but the play was still there.
Removing the diff revealed that the diff bearings were shot.
As I was going to fit a more powerful engine, this seemed like a good time to alter the gearing to lower revs at cruising sped, so a s/h 3.9 to one diff was purchased from Mech Spec and fitted.
The play in the bearing had disappeared and driving at 65-70 was now more comfortable due the engine revving less.
Out for a spin one morning, I noticed it was coming up to 1000 miles, and there is a road in the next village called "Roger’s Road". Driving around side streets for a while enabled me to drive up "my" road as the car reached 1000 miles.
I had spent a considerable time thinking about the replacement engine.
My mini had 110 bhp at the wheels, but would not pull under 4000 rpm and had to be rebuilt far too frequently. I wanted more power, but without rapid engine wear and unreliability.
A winter of reading had convinced me the way to go was supercharging, but although I had been to several autojumbles and contacted dozens of s/h parts suppliers I was unable to find a suitable kit.
3 or 4 superchargers were available on their own, but I had decided from the outset that I would only buy a complete kit; I did not want the aggro of designing/fabricating mountings and manifolds.
I decided it was back to a hot 1275.
Several years ago I had bought a marina 1300 short engine with a view to fitting it in the Arkley, I also had a 12G940 head, and my Mini was originally fitted with a Weber DCO45E, which I had to remove because it was not homologated for the series in which I raced. (I told you I never throw anything away)
I sorted these parts out and stood them near the bench in the garage, I find it helps my little grey cells if I have something to look at.
About a week later "enjoying M.G." dropped thro the letterbox. In the "spares for sale" section was a complete supercharger kit for a Morris 1000!
I made arrangements to go and view the supercharger a couple of evenings later, to be told that a couple of other people were interested and the seller wanted us all to make an offer and the supercharger would go to the highest bidder. The others were coming to view during the coming week.
I went home disappointed that I had not been able to purchase the supercharger there and then and pondered how much to bid. I eventually put in my bid and there followed one of the most agonising weeks of my life, as I was so excited of the thought of actually getting the supercharger, but also knew it could be such an anti-climax. Eventually I got a telephone call to say it was mine, but another agonising 24 hours passed until I actually had it in my hands and could relax.
I now had to go through the exercise of deciding what engine to build again.
The first thing to do, was fit the supercharger to the existing engine to see how it fitted andb to establish exactly what I had got and what problems there were likely to be.
The first problem was that the blower fouled the long centre branch exhaust manifold, so this was removed and the blower offered up again – the bottom hose was now in the way, so this was removed and now the blower could finally be fitted.
It was obvious that there would be minimal clearance (1mm?) between the 3 Vee blower pulley that replaced the existing crankshaft pulley, and the front cross member, so I made a note to buy an emergency fan belt.
Closing the bonnet posed a problem, the carburettor dashpot being about 6mm to high.
Basically I had proved it would fit, and I had most of the bits.
The blower vendor then mailed me and told me about a web site for British Classic Sports cars, who specialise in second hand superchargers and are very knowledgeable about Sprites.
That website confirmed that the LCB exhaust manifold would have to be modified to fit, or replaced, and also that the Sprite carburettor pipe was angled so as to lower the carburettor, but the Morris one I had was straight. As a second hand pipe is over £100, I think I may end up with a hole in the bonnet!
The blower was removed from the car and fitted to the original Sprite engine, along with the 12G940 head, so that I had something to look at while I pondered further.
It was now march 2001, and I decided that it would be a good idea to modify the dash area to fit the boost gauge, before I started to use the car regularly again, also the temperature gauge had failed, and this definitely needed sorting before a new engine was fitted.
The dash was duly removed; along with the auxiliary bracket I had made for the ammeter, interior light, and illuminated (badly) reversing light switch and auxiliary (cigarette lighter) socket.
As I had fitted twin stalks on the steering column, I had a spare switch on the dash board, so I drilled a hole next to the bottom left switch to take a warning light, and wired this up as a replacement reversing light switch.
The two small holes on the auxiliary panel that had taken the reversing light switch and auxiliary socket were now enlarged into one large hole to take the boost gauge. A small bracket was made to mount the auxiliary socket behind the boost gauge, facing into the passenger foot well.
At the same time some instrument lights that had not been working were sorted.
I had been thinking about the engine. A 1275 block was taller than the small bores and would mean a new supercharger mounting plate – the font of the supercharger mounts on the timing cover, the back on the inlet manifold. Also, using a Marina block would mean using the Sprite crank (rendering the rest of that engine useless) or modifying the Sprite flywheel to fit the Marina crank.
After various deliberations, I decided that as the Arkley is non standard and fitting a supercharger is not that common, I would go non standard on the engine, retaining the original sprite block, but over boring it to take Hillman Imp pistons, that would give it a capacity of 1220cc.
Who would build this engine?
Looking through the MGOC list of recommended suppliers I recognised the name of Anglian Engine Services at St Neots and remembered that I knew Ian from when he used to race an Anglia in a sister series to the one I raced the Mini in. If he built his own race engines and I knew him, I decide he was the man for the job.
A phone call renewed an old acquaintance, and subsequently a boot full of bits was taken to St Neots, and a spec was discussed – bore to take Imp pistons, flow and port the head a bit, block off bypass hose position + add two extra stud holes to block, (Ian suggested APT head studs), grind crank, fit fast road cam + all the other normal bits. He would strip and clean the blower, match the inlet manifold to the cylinder head and machine a hole in the supercharger mounting plate to improve airflow to the exhaust. I told Ian I wasn’t in a hurry, which was just as well as it turned out!
I then took a trip to MG Mecca out at East Harling near Snetterton were I exchanged my original broken gearbox for a reconditioned one, (I had decided that with the extra power and torque of a supercharger that it was no longer to fit a close ratio gearbox, as it would probably be unnecessary to change down gear to overtake) and also purchased a second hand anti roll bar and also a cast exhaust manifold + a Peco big bore exhaust system. At the sane time I also bought new engine and gearbox mounts ready for the transplant.
I had purchased some EBC grooved discs and ‘greenstuff’ pads at Stoneleigh about a month earlier, and these along with the anti roll bar were fitted to the car. We were now on 1230 miles.
During the summer we went to several events at clubs I belong to, winning the ‘Car most people would like to take home’ Trophy at the Cambridgeshire MGOC concours evening, performed miserably at the ‘Newmarket and District Car Clubs’ Driving skills test (having won it the previous year) and eventually made it to a MASC meeting! (At a subsequent meeting I was able to purchase a certain out of print book at a favourable price!)
During this time I had periodically phoned up to see how the engine was progressing, and eventually on the 21st of September I was able to pick it up – only time will tell whether it was worth the wait.
The supercharger had been stripped and Ian had decided that it would be prudent to fit some new bearings, but hopefully it would be ready in a couple of weeks.
Two days later we drove down to Brooklands where after Sixteen years of owning an Arkley I actually got to see another one close up and speak to the Owner!
We are now on 2442 miles.
I had an alloy rocker cover kicking about that had been on the racing Mini at one point, and decided to use this on the new engine. It was a bit tatty and painted in a black that did not match the black of the engine. I polished up the bare bits and painted the rest in red engine lacquer and bolted it in position with a pair of chrome plated ‘T’ bars. A friend of mine from the MGOC had engraved some Arkley badges, a silver one that I had fitted to the dash in place of the Sprite badge, and a red one that I screwed on to a plinth on the rocker cover – thanks Ray.
The ignition does not need as much advance with a supercharger as it does without, and as the distributor in the car was fairly old so I decided to purchase a new distributor from Aldon with the correct advance for the engine and also to alleviate the problem of continually resetting/replacing points I also specified an electronic ignition module – this fits inside the distributor cap so apart from no vacuum advance the distributor looks original. (Why am I worrying about originality!!!!!) The distributor arrived a few days later and was fitted to the engine. I will modify the old distributor in due course to carry as a spare.
The clutch was now fitted to the flywheel.
Next item to fit was the water pump, straightforward unless your name is Roger.
I found three aluminium and two cast iron pumps around the garage and none of them would fit; yet these were all pumps that had been fitted to ‘A’ series engines at some point. The extra stud that had been fitted to the front of the cylinder head protruded through into the water jacket and fouled the pump impeller. This was simple to remove, modify, and refit, and then ONE of the pumps would fit. Why?
I read the cooling chapter in David Vizard’s bible on tuning ‘A’ series, but could not find any reference to this problem.
I looked at the engine in the car – smaller bore heads have clearance on their undersides underneath the thermostat area to clear the pump, 1275 heads do not need this as the block is 3/8inch taller, and the cast iron pump that fitted had been modified by someone earlier by removing metal from its top face.
I modified an aluminium pump to suit and tapped the bypass hose boss and ‘glued’ a suitable bolt in place to blank it off.
Having read the section on cooling, I decided to fit a modified (add two 1/4inch holes) thermostat rather than a blanking sleeve, as this would reduce the warm up time.
Next problem, the thermostat housing studs on a 1275 head are in a different position to the 1098, but as the 1275 car uses a cross flow radiator and different thermostat housing this is not a problem – using a 1275 head with a vertical flow radiator is, the outlet pipe is about 30 degrees out of position.
There was a restoration show coming up soon at Stoneleigh, so this seemed like an excuse for a day out.
Walking around the cars for sale I noticed that the thermostat housing on early MGB’s appeared to be at the angle I required, so one was duly located and purchased at the adjacent autojumble for a couple of quid.
I also found at the autojumble an aerofan, now for those of you who are not familiar with these, they are fan blades that are sprung loaded and feather like aeroplane props as engine revs increase.
I had fitted one of these to an 850 Mini years ago, because the original fan absorbed nearly 10% of its meagre 34bhp. The aerofan passes the same amount of air at tick over, but as engine speed increases it feathers and passes less air, absorbs less power and is quieter. As normally an increase in engine revs is an increase in speed, the ram effect of air passing through the radiator provides adequate cooling and the fan is superfluous – hence the introduction of electric fans.
I had been planning on fitting an electric fan, but here was a piece of period nostalgia that I could not resist, and it would be easier to fit.
On returning home I found that the ‘B’ thermostat housing had a larger inlet pipe than the ‘A’ series and the fixing holes were in a slightly different position. Using soap as a lubricant, I managed to stretch a new top hose on to the housing, and filing about 1mm out of the fixing holes got it to fit.
I found some longer bolts and fitted the aerofan (it is quite a lot thicker than standard fan blades).
When using the original fan blades with a supercharger you have to fit a 5mm spacer between the blades and water pump to stop the blades shredding the supercharger drive belts, but it looked as though the aerofan would clear.
The only job left to do before fitting the supercharger, was to fit the inlet and exhaust manifolds.
Having done that, I phoned Ian to find out when the supercharger would be ready- I could pick it up in a couple of days.
It was easy to bolt the supercharger on to the engine, now there are only a few things to sort out before I would be ready to carry out the transplant.
I needed drive belts, spark plugs (colder than normal), oil feed pipe, sort out carburettor, choke cable, throttle cable and air filter.
I had spoken to fellow MASC member, Chris Yates, about his supercharged Sprite earlier on in the year, and decided to email him with a few questions before proceeding. Chris was able to clarify a few points, and so I set off to source more bits.
Past Parts in Bury St Edmunds were able to supply to belts of the correct length (I think) to drive the blower, and some N4 spark plugs. A nearby engineering shop made up a braided oil hose to suit, although this is quite large in diameter and is probably more suitable for a Jumbo’s undercarriage than feeding a pint of oil every 1000 miles to a supercharger and did pose a further problem.
I had to use a bit of force to fit the drive belts, there is no adjustment, and they are tight, but I am sure they will stretch quite quickly and should be O.K., and the aerofan does clear.
Getting back to the oil pipe, I had fitted a ‘T’ piece in to the oil pressure gauge tapping on the block, but the oil pipe union was so big that it fouled on the engine back plate, and the oil pressure gauge pipe did not look as though it could easily be bent at right angles to go in the side tapping of the ‘T’.
Apparently, an alternative pick up point for the blower oil feed was to tap the banjo bolt on the feed pipe to the oil filter housing. This would make it difficult to fit an oil cooler in future, but I do not think one is necessary on a road car, and if used in winter it would have to be fitted with a temperature switch to stop the oil from running to cool.
My everyday car is currently an MGB GT, and when I change the oil I that I think it is a waste of time as the new oil will immediately get mixed with a pint of old oil left in the cooler. On my racing Mini, I used to unbolt the cooler and hang it from the garage roof to drain when I changed the oil, but this is not possible on the ‘B’ as the oil pipes pass through the radiator mounting panel.
So, as I do not intend to fit an oil cooler to the Arkley, I tapped the end of the banjo bolt, but instead of taking the oil feed to the blower from here, this is where I will plumb in the gauge, the blower feed will come from the original gauge tapping. Why? Because the banjo bolt comes before the filter and I think that is essential to feed filtered oil to the blower, where as I couldn’t give a t??s about the gauge.
The next stage was to fit the bottom hose, I had already bought a set of hoses, and BCSC supercharger fitting instructions said that all you had to do was to bend the original hose behind the timing case and use another piece of pipe to extend it forward to meet the radiator. I had already sourced a suitable piece of copper pipe for the extension.
I was not surprised when this proved more difficult than it sounded, especially as the only straightforward thing about this sodding supercharger had been parting with the money when I bought it!
A used hose already clamped to an engine may have fairly pliable and easily bent over the timing cover, but this new piece of Kevlar reinforced rubber weren’t having it! Well not without distorting and snagging bolt headson the back of the blower mounting.
As I sat on the garage floor looking at this latest little opportunity to sort something out, it occurred to me where as the Sprite hose drops down vertically from the water pump, a Mini hose is curved and follows the shape of the timing cover. Within a few minutes I had found three hoses, one slightly longer (top to bottom) than the other two. This longer hose, when fitted to the engine, rolled over the timing cover beautifully and exited between the engine mounting and timing cover. BRILLIANT.
This was a vastly superior fit to the original hose, but did just chafe on the top of the engine mounting plate between the timing cover and the engine mount – simple solution – remove blower – chop lump out of engine mounting plate – replace blower.
Now all I have to do is source a new hose.
The next week saw me popping in to Marshalls in Cambridge armed with hose, and eventually three parts people, probably with in excess of fifty years in the trade were looking at this pipe.
Two were convinced it was Mini Clubman, the other either Morris Marina or Mini Clubman, but whichever it was obsolete and they could not supply one.
A call to a local Mini specialist confirmed that a Clubman hose was longer than a normal Mini and he could get one.
I went to pick it up – he meant longer in the radiator stub, I wanted longer top to bottom – this was not the one!
I remembered that my racing Mini had at one point been fitted with an 1100 radiator – a call to a company that specialises in BL transverse engined vehicles confirmed that the 1100 hose was taller than the Mini, but again it was obsolete although they have some second hand ones.
Well, at least I have a hose I can use in the short term and I am 99% certain what it is, so I may be able to find a new one at some time.
Another cause for concern for some time had been the carburettor that had come with the supercharger. It did not have a throttle lever or any connection between the choke and throttle as most SU’s have, indeed the bosses on the body where this linkage would normally pivot had been removed. I had a book on SUs from 1960 to 1972, but mine was not listed, also I had been hawking it around autojumbles looking for something similar without success. I had been told by one carburettor specialist that it was basically in good condition, but the butterfly seemed to operate backwards.
At the restoration show at Stoneleigh I had been given some magazines, and in one of these I spotted and advert for Burlen Fuel Systems, who apparently had taken over the rights to SU.
I sent an email to BFS with all the information I had on the carburettor and they phoned me back the next day to say that the choke/throttle linkage was not fitted to this carburettor originally and was not required with a supercharger, also they could supply an overhaul kit and throttle levers of various lengths.
I knew that I was also missing a throttle cable mounting plate, so decided that as I knew I could use the carb, I would wait until the engine was installed before I finally sorted it out.
It was now early December, so I took the Arkley outside and gave it a wash, deciding that I would not be using it any more before the engine swap.
We are now at 2580 miles.
There were two other jobs that I decided I must start before the engine swap, and these were to make a crankcase breather to fit onto the side of the engine where the petrol pump fits on A30s (I had already modified the block) and to modify the nearside wheel arch of the bonnet – this protruded forward of the sill by half an inch and the wide tyres rubbed on it occasionally when carrying a passenger.
I found a piece of 3mm thick steel and cut it to the shape of the petrol pump mounting, drilled suitable holes in it and then riveted a right angle brass plumbing fitting into it. This was then bolted to the engine.
I will fashion a pipe after the engine is in place, along with other pipes from the tappet chest and rocker covers.
Before I knew it Christmas was here, and I was the lucky recipient of a MASC fleece and a book ‘Modified Midgets and Special Sprites’ by John Baggott – well worth a read if you are interested in modified Spridgets.
Between Christmas and new year I modified the offending wheel arch and also knocked up a mud flap that I intend to fit to stop stones etc. bombarding the protruding rear wheel arches.New year – new engine.
The existing engine and gearbox were removed and the rebuilt engine (c/w supercharger) and reconditioned gearbox were fitted using all new mountings. Prop shaft, starter, alternator, dizzy etc. were then fitted.
The carb was bolted to the carb pipe, the choke cable would fit but the throttle cable was about a foot short.
The radiator was in a sorry state, although it didn’t leak – both side plates had become detached from the header tank, and the header tank had a large dent on the top on one side and a large bulge on the other.
I decided that this was not suitable for exchange, so I took it to Serck to rebuild.
The engine and gearbox were filled with oil and the engine was turned over - - - - oil pressure!!
A Marina throttle plate was modified to suit and an MGB throttle cable was found to be the correct length, although the nipple at the accelerator pedal end was far too large and had to filed down to suit.
At this point I took a day off work and drove down to Burlen Fuel Systems near Salisbury to get the missing bits for the carb and one of their nice shiny chrome air filters.
The next job was to offer up the exhaust, and as expected it was too long – the Arkley being somewhat shorter than a Spridget - and I decided that the only way to shorten it was to do away with the ‘S’ bend behind the axle and have the exhaust come up at an angle from behind the axle to finish just below the rear bodywork.
I cut the exhaust in to two pieces in the middle of the ‘S’ bend, and with the front part mounted on the car offered the rear part up to gauge the angle. I then cut both parts and tacked them to-gether.
After a couple attempts I got the position right and called on my cousin to do the final welding.
The tail pipe now came up at an angle, and I remembered that I had to cut the curved chrome tail pipe off the previous silencer I had fitted in 1985 – as I have said before I never throw anything away – and looking through one of my buckets of ‘rubbish’ I found it.
It was a perfect fit, so a couple of inches was sawn off the new exhaust and the tail pipe was welded on.
While the car was up in the air I replaced the rubber pads on the rear axle, as they were probably the originals and had become quite hard.
The radiator was now ready for collection, and although the header tank is not perfect it is considerably better than it was – time to fit the cooling pipes.
I had purchased a length of brass tubing to extend the bottom hose (which now had to go behind the timing cover) to the rad, but to my disappointment found that the 1100 bottom hose that I thought was going to cure most of my problems was not tall enough.
The 1100 hose was cut in half and extended by about 2 inches with one piece of brass tube, and the upright part of the new Spridget hose was cut off and used to join the rad to the bottom of the 1100 hose with another piece of brass tubing.
With the rad and all the other cooling pipes fitted, the temp gauge sensor was fitted and the system filled.
Using the MGB thermostat housing was straight forward, the top hose just needing to be shortened by about an inch.
Time to fit the breather pipes.
I used reinforced plastic hose for the three pipes, one from the tappet chest cover, one from the additional breather I have fitted to the side of the block, and one from the rocker cover.
A right angle bracket was made and bolted to the bracket that holds the inner wing to the radiator mounting, and a half gallon plastic container was strapped to this after I had put in holes for the breather pipes.
The boost gauge was connected to the manifold and a second superfluous connection was blanked off.
The carb was stripped, cleaned, and rebuilt and refitted and cables connected.
Time to fire up.
After charging the battery the engine burst into life and the revs rose and rose! Switch off.
Try with less choke – same result. No choke – same result.
Investigate – throttle operating butterfly in wrong direction, so pressing the throttle reduces the revs!
Now, this would make a cunning anti-theft device.
Maybe it would be better to make a new throttle plate.
This done the engine ran sensibly and I ran it for 10-15 minutes to check for leaks /temperature – all appears O.K.
Before I put the car back on the road I wanted to fit a locking cover to the boot, as I knew that if I didn’t do it now it would never get done. This done I fitted the gear lever, carpet, and seats.
It was now time to fit the bonnet and sort out the interference with the carb dashpot.
The bonnet was fitted and closed, and it did close! How come? I can only think that facing the block and skimming the head has lowered the carb enough to give clearance, albeit only 1mm.
Time for a road test – 10 mile run shows good oil pressure and temp O.K. (if anything too low), but throttle does not shut off properly, possibly because cable is now an ‘S’ shape.
The speedo problem proved to be a combination of worn inner cable and worn speedo drive in gearbox.
A new cable was fitted and the drive swapped for the one in the box I had just removed.
A stronger spring ensured the throttle closed.
It is now early March, so I use the car for work a few times as the weather is quite good.
The carb hits the underside of the bonnet under acceleration, so that needs sorting, because I have no linkage between the choke and throttle it will not tick over until it gets warm – I will live with this in the short term, summer is coming!
A week later I sold my every day car (MG B GT) so I will have to use the Arkley for work until I get a replacement.
After a couple of weeks it has done 400 miles, I am now using more revs and finding it quite lively, and the acceleration from 40 to 60 in top seems quite incredible.
Apart from the carb, and running a bit cool there does not appear to be any other problems, so in a few more miles I will change the oil and book it in with Peter Baldwin to have it set up on the rolling road.
After 17 years is the fun really going to start?