Articles

See Mini FAQ Part 1 Engine A-series vs. A-plus engines Adjustable oil pressure release valve construction/installation Automatic to Manual conversion Block oil/water connections - threads Donor cars with compatible A-series engines Engine Mounts - aligning and bolting up Fitted new extractors/intake/stage 1 kit, engine now runs rough Fuel Injection conversion How to build a quiet engine Oil filter replacement - cartridge type Oil filter - cartridge to spin-on conversion Oil pressure problems caused by relief valve - ball bearing mod Painting engine/exhaust South African 1275cc engines Swapping engine - driveshafts do not fit into inner CV joints Which cylinder is No. 1? Fuelling Is there a list of SU carb needles/specs? SU carburettor spring chart Twin SU carburettor setup does not fit Unleaded petrol and your old Mini Unleaded petrol - is my Mini designed it? What do HS2/HS4/HIF44/etc mean? Which carburettor is best for me (Weber/SU/etc?) Gearbox Differential tips Instruments Changing the speedometer cable Fuel gauge reading incorrect Fuel gauge and temperature gauge reading incorrect Temperature gauge reads high Suspension Changing inner driveshaft joints Checking/setting toe-in Disc brake hub reconditioning Front hub nut keeps coming loose Replacing worn/broken suspension parts Reassembling ball joints Splitting ball joints Suspension cone compression tips Engine A-series vs. A-plus engines The A-plus engine is the result of development efforts carried out on the A-series engine in the late 1970s/early 1980s for the Metro. The A-plus engine was available in 998cc and 1275cc forms, and very briefly in 1098cc form. The blocks and gearboxes were introduced to the Mini range at different times starting in the early 1980's. Key features are: Increased block strengthening plus thicker gearbox mounting flange. Gearbox and drop gears redesigned for lower noise and increased strength. Dipstick is incompatible between A-series and A-plus. Alternator brack altered. Distributor clamp altered. Verto clutch (reduced pedal effort). A-series and A-plus engines are interchangeable, though gearboxes are only interchangeable if an adapter drop gear is used. Adjustable oil pressure release valve construction/installation (This article is originally by Marcel Chichak) The problem with the design of the pressure relief valve is that the valve plunger is a cylinder which is tightly confined along its length. One small shaving is all that's needed to cause it to jam open or closed. All that's really required is enough of a valve to seal against the seat. A ball bearing can replace the plunger and get around all the problems. Here's how it's done: Remove the oil pressure relief valve dome nut (1" wrench). Remove the pressure spring. Insert a finger into the hole and extract the plunger. Drill and tap a 5/16" UNF thread in the centre of the dome nut, thread a nut onto a 2" bolt and screw it into the dome nut. Cut 3 coils off the pressure spring and roll the last coil over to make a nice square bearing area. To be able to use the bolt as an adjuster, you'll need to ensure the spring bears upon it properly. This can be accomplished by either rooting around until you find an appropriate washer, or make up a thin steel disk which just fits inside the diameter of the dome nut. Obtain a 1/2" diameter ball bearing. CV joints are a good source for these, or go to a bearing supply shop who will likely just give you one since it's not worth their while to write it up. Insert the ball bearing, then the spring and capture it all with the dome nut. Screw the adjuster all the way out and start the engine. Watch the pressure gauge closely: if it reads: >60 PSI, shut the engine down and take another coil off the spring; ~55 PSI, close enough, you've earned your brew; <50 but>20 psi, go to the engine and screw in the bolt until the gauge reads 50 PSI; <20 PSI, you've buggered a spring and you need to find another one! Mine ended up needing 4 coils cut off, but I started with 3. Once you've set the pressure you want, I recommend 50 PSI, set the lock nut. An interesting thing about this setup is that the oil pressure stays at 50 PSI. Cold starts with thick oil: 50 PSI. Hot starts with thin oil: 50 PSI. Highway running at 90 MPH: 50 PSI. Hot idling: 50 PSI. If the oil pressure flutters or varies widely, shorten the spring and pack the space between the spring and dome nut with washers to reduce the operating range of the release valve. Back to Top Automatic to Manual conversion The easiest method of converting from automatic to manual transmission is to fit the engine and front subframe from a manual car. The automatic engine can be fitted to a manual gearbox, but about the only compatible components are the block and head. The block needs the following modifications: a spacer for the pump recess, two holes drilled at the oil filter mounting boss, a drilling to the pump through the pressure relief valve passage, replacing of the relief valve seat for a undrilled one (factory mod). You also still need a manual gearbox, clutch, driveshafts and front subframe. Other parts needed: gear shift, clutch master cylinder, and pedalbox from a manual car. Block oil/water connections - threads The oil pipe connection out of the block and the temperature sender are both tapped for 5/8 BSP fittings. Donor cars with compatible A-series engines The following cars have engines that are bolt-in compatible with the Mini. The only major differences are likely to be the driveshaft coupling type and gear change; the gearbox/differential may be changed to suit the car, or the car's driveshafts may be swapped for compatible ones, and a hole for the new gearshift made in the floor. In all cases, these donor engines use driveshaft joints and gearshifts compatible with the Mini equivalents; Mini gear shifters of the appropriate type should be used. Compatible donor vehicles: Austin Allegro 1100/1300 Austin/MG Metro Austin/Morris/MG/Wolseley/Van den Plas 1100, 1300, 1300GT Other cars that used A-series engines such as the Sprite/Midget and Morris Marina and are not compatible because the engines are in-line, not transverse. However, the cylinder heads are compatible, and the blocks may be adapted for transverse use by modifying the oil pickup and centre main bearing cap. Non-Mini twin-SU manifolds may cause the twin carburettors to foul the bulkhead. Back to Top Engine Mounts - aligning and bolting up One of the most-hated Mini jobs is to line up the engine mounts with the mounting holes in the front subframe and installing the bolts when installing the engine in the car. Some tips: Find someone with small hands to help you. To align the mounting holes, keep some upwards pressure on the engine via the hoist/winch you are using to drop the engine in. Rock the engine from side to side to get the holes nearly lined up. When they are close, use a plastic-insulated screwdriver through the part of the mounting hole that is visible, to move the mount around until it lines up. Alternatively, lift the engine up about 2cm off the subframe and use an old plastic-insulated screwdriver or similar to line up the mounts via the subframe holes before lowering the engine completely. If you can get one bolt installed (but not tightened up), lining up the remaining three holes is much easier. Each time you get one hole to line up, install a bolt in it (do not tighten up). To get the bolts through the mounts, wrap thin wire (e.g. welding rod) around the thread of the bolt and manoeuver the bolt into place by remote control using the wire. As soon as the bolt goes through the hole, put a nut on it and pull on the wire - it should unwrap leaving the bolt in place. Engine mounts with captive nuts are available that do not require the bolts to be installed from the subframe sides, making the whole task slightly easier. Fitted new extractors/intake/stage 1 kit, engine now runs rough If the engine runs roughly or idles at a very high speed after installing a new intake manifold or exhaust extractors, an air leak is the likely cause. This is often caused by the flanges on the new exhaust manifold being of different thickness to the intake manifold or vice versa. Since they share mounting studs, one of the manifolds will no longer be sufficiently tightened up to the head. This is often the case with "budget" type manifolds. Back to Top Fuel Injection conversion Fuel injection systems consist of a number of sensors and actuators, plus a computer to control them. The retrofitting of a custom-made system to a non-injection engine is a complex task. Instead, it is recommended to source a 1.3TBi (single point) or 1.3MPi (multi point) Mini engine and ancillaries, and modify or replace the ECU (engine control unit) if desired.For a detailed introduction to fuel injection systems consult the Haynes automotive electrical manual, or similar books (available at the local library). The following article (slightly edited) describes a fuel injection conversion using standard Mini components. Date: Wed, 15 Oct 1997 02:03:24 +0100 From: bordewyk-at-dds.nl (Arnoud Bordewijk) Subject: long and kinda tech: The full Parklane Tbi story As promised here's the recipe to create an electronic injectionized mini: You require: 1 unsuspecting carby mini 1 preferable complete but totalled Tbi mini 1 spare MG-Metro (or other) cam. Lots of patience some tech. knowledge (like: to fasten; turn clockwise;-) (I think an ordinary (unleaded) 1275 engine will do fine as well) I started by taking the Tbi apart (I bought it as a (totally bent) runner). I'd done some research, and found out the only difference in engine between standard Tbi and Cooper Tbi was a higher CR on the Cooper (probably by means of shorter block and different pistons (less deep dish), because the heads are the same), and a different computer. Since my goal was a little more than the standard 54 Hp, I had the head skimmed to get the CR a lttle over the Cooper's (some 10.3 vs 10.1 (9.4 is standard Tbi). It's also possible to go to a hairier cam, since the MEMS-ECU (Modular Engine Management System Electronic Control Unit) can adapt to "new" circumstances. I opted for a MG-Metro cam; 1. because I read in Minimag that 255 deg is the fastest cam that still makes for a "civil" engine (I do a lot of village/city driving), 2. because it sat jobless on a shelf in the garage. I didn't bother with changing the followers since it was a used cam (we'll see if this was a good plan;-), and I didn't feel like separating the block and 'box. First I removed the head and send it to the machine shop to be skimmed. Then I tilted the unit on the bellhousing (using some wooden blocks for support), and turned the cam a few times before lifting it out vertically. This made sure the followers were way up in their bores. Then I lowered the 'new' cam in the same way. It was precisely on time, but DV writes that this cam works best if timed in at 106-107 deg instead of 110, so this I did. I put the engine together and gave it a nice fresh coat of red paint. I wanted to ditch the cat, because I didn't feel like buying a new RC40 rear section when I had a 1 year old Maniflow LCB/RC40 system already. This was one of the most complex things: the original Lambda sensor had to be retained, but in my LCB there was no hole for one to fit, on top of that for some reason the thread on the sensor is neither metric nor UNF (but Bosch' own I guess). Luckily with the Tbi came a section of manifold, from which the correct nut, was ground out and welded to my LCB. Then: horror! When I offered up the LCB to the engine (still not in car), the lambda sensor fouled the fuel pump blanking plate:-( Had to do that all over again. It also turned out the intake manifold's water cooling pipe fouled the center branch. You have to use it because the temp. sensor is in the throttle body now. I had to heat the pipe up really well and had to bend it totally to make it clear the branch. I also applied some DV tricks to the butterfly and spindle (slimming spindle down, knife-edging butterfly and removing butterfly screws' split ends). After all that I turned to the poor old Parklane, who was suspecting something by now, since his engine had been removed and dropped into the Mayfair to have at least one car on the road. I removed the interior (just for easy acces) including wooden dash and switchpanel (to be replaced by 5 switch type), steering column and pedalbox, heater, fuel tank, complete clutch system, wiring loom except the rear section and master brake cylinder (+ front brake pipes, which needed replacing anyway). Then came the process of planning fuel line routes, putting in the new (2 section) loom in the engine bay (I used some of the rear section too, but that's later). I bought 6 metres of rubber fuel line and laid it out; it was only just enough, since there's a return line as well. It now goes through the 'gap' between rear seat upright and rear wing panel, then through a drilled hole in the LH companion box, along the floor, through holes in the crossmember, upward along the bulkhead and it comes through the bulkhead a bit to the right of the clutch master cyl.,from where the original pipes lead to the injector housing. Nearly the same route is followed by the rear section of the Tbi's wiring loom, which is used only for the in-tank-fuel pump and the screen washer bottle, which now sits in the LH companion box (keeping it a bit warmer during winter, but it's really noisy!). Finally time to fit the engine, which was not anymore difficult than usual. Fitting all the wires and hooking up all sensors took me a full day. Then came the big moment; I turned the key to II, the ECU clicked and the fuel pump span. I turned the key to III and it cranked, but that was all:-( No fuel from the injector and no spark. At first I was affraid I had made a bad connection and blown the ECU, but that didn't seem the case, because when I took the key out, it made another clicking noise (which Johnmar told me it was supposed to do). So I tore out the injector, thinking it might be blocked, but that wasn't it. In the end I phoned the dealer. He told me to check if the flywheel TDC sensor received signals. It then started to dawn on me that I could have fitted the wrong flywheel. I ran to the garage and in the corner it sat, waving it's reluctor ring at me;-). After I fitted it the next day the engine burst into life on the third stroke :-). The car is a lot quieter now (when stereo off:-), because I also fitted the more extensive Tbi sound deadening material. I've now driven it for some 70 miles and the ECU is adjusting quite well. At first it would stall when I took my foot off the loud pedal, but it now happily idles at some 850 revs. The plugs have a healthy color and it pulls like a train from 2000 RPM (probably due to the MG cam). At 60 Mph there still seems to be enough power left, but I'll try that once it's all a bit settled. It also apears to be economic, because in 70 miles, the fuel gauge is now just below the top mark:-) In all I think it was a succesful operation, but it requires plenty of time (I took my time: 2 months, in odd hours and a number of full days) to do properly. Back to Top How to build a quiet engine Replace the noisy components with quieter (expensive) ones and lower the revs. Belt drive cam kit. Roller rockers. Carbon fibre push rods. Alloy rocker cover. Fit the lowest-ratio diff that is suitable for your application. Use an A-Plus block and gearbox. Fit an electric fan, preferably with front-mounted radiator. Oil filter replacement - cartridge type Owners of earlier Minis, particularly vans with non-removable grilles, may find changing the cartridge type oil filter easier if the filter is removed by unbolting the filter head from the engine with the filter case still attached, then replacing the filter on the bench. This method makes fitting the rubber o-ring seal in the filter head far easier, but requires a new oil filter head gasket at every oil filter replacement. A suitable gasket can be made from gasket paper for minimal cost. Oil filter - cartridge to spin-on conversion Early Minis may be converted to the later type spin-on oil filters (which are easier to change), by fitting the filter head and feed pipe from a later engine. If the car has any collectible value, retain the original parts so the car may be returned to original specification. Oil pressure problems caused by relief valve - ball bearing mod Many A-series engines, especially 1275cc, suffer from low or inconstent oil pressure. If this is not caused by a worn crank or bearings, it is often caused by the oil pressure relief valve. This can get jammed or partly stuck open, leading to low oil pressure readings. A common modification is to remove the oil pressure relief valve plunger, cut a coil or two off the relief valve spring, and replace the plunger with a 9/16" ball bearing (that can be had from a bearing company or an old CV joint). To start with, cut one coil from the spring, then start the engine. Remove more coils until the oil pressure is around 60 psi (any more is wasteful, a lot more will just force oil to leak from the engine). Oil pressure should be relatively constant over the rev range with this modification. Painting engine/exhaust Engine lacquer and exhaust enamel can be purchased in brush or spray form from automotive accessory shops and automotive paint shops. Exhaust paint is designed to withstand far higher temperatures than engine paint which will burn off. When painting the engine or exhaust, the surface must be clean, free of dirt, oil, grease and rust. Clean using degreaser and a wire brush, and remove surface rust by sanding; exhausts may be media blasted. No primer coat is needed. Mark 1 engines are painted green, but there is no paint code for this colour and it varied from batch to batch. Mini specialists can supply the correct colour paint. Back to Top South African 1275cc engines South African 1275cc Minis used the Morris Marina engine block and oil filter. In the Marina, the engine in installed in-line rather than transverse. This block is also used in recent Minis with front-mounted radiators. Swapping engine - driveshafts do not fit into inner CV joints The internal diameter of the inner CV joints were changed circa 1978. Therefore, the driveshaft-end of the joint from a post-'78 car will not fit in the "cups" on either side of the differential on a pre-'78 car, and vice versa. The solution is to remove the inner CV cups from the old engine and install them on the engine that is being installed - drain the oil first. Which cylinder is No. 1? Cylinder no. 1 is the cylinder closest to the radiator (pre-1996 cars with side mounted radiators), or the cylinder furthest from the clutch. Back to Top Fuelling Is there a list of SU carb needles/specs? There are several hundred SU carb needles. Full details, including needle profiles, can be found in the Haynes SU Carburettor manual. Alternatively, Burlen Fuel Systems (present manufacturer of SU carburettors) can supply a list. SU carburettor spring chart Colour Load (oz) Length (in) Black, green 5.25 2.5 Light blue 2.5 2.625 Red 4.5 2.635 Yellow 8 2.75 Green 12 3 Brown 14 3 White 18 3.625 Red/Yellow 24 4.812 Red/White 40.5 3.875 Red/Green 11.25 3.875 Lt. blue/Block 4.5 3.875 Lt. blue/Red 18 3.875 Red (HIF carb) 4.5 1.53 Yellow (HIF carb) 8 1.53 Green (HIF carb) 12 1.53 Twin SU carburettor setup does not fit The manifold is probably from a Sprite, Midget or other in-line engined A-series cars. Mini manifold casting numbers are: AUE 1014 - twin 30 degree HS2s AUE 1019- twin H4s (Special Tuning) AUE 1015- twin HS4 (Special Tuning) Other casting numbers indicate manifolds from other twin-carb A-series engines. Back to Top Unleaded petrol and your old Mini In many countries, unleaded petrol is unavailable, or soon will be. This is a cause for much concern among Mini owners, since Minis made before 1990 are not designed to run on unleaded fuel. The lead in leaded petrol is in the form of a compound - tetra-ethyl lead. It is added to petrol to cool and lubricate exhaust valves and valve seats, which would otherwise be damaged by the very hot exhuast gases that pass across their surfaces. This damage includes pitting and cracking, and rapid valve seat wear (known as valve seat recession). Eventually, the valves will fail to seal fully against the combustion process of the engine, requiring the cylinder head to be repaired. Inlet valves do not suffer from this problem, as they are closed when the exhaust gas is leaving the engine cylinders. The exhaust valves and seats of modern cars (including post-1990 Minis) are made of tougher material that can withstand exhaust gas temperatures without damage. There are a number of solutions available to Mini owners: Use a lead substitute, injected into the tank before filling. In New Zealand, a reputable product called "Valvemaster", manufactured by Associated Octel (previously a large supplier of tetra-ethyl lead to oil companies), is available from all gas stations and adds about 4% to the cost of filling a Mini with fuel. It has been endorsed by the four international oil companies in operation in NZ and conforms to Australian government standards for elimination of valve seat recession in testing commissioned by the New Zealand Automobile Association. In countries where the option of leaded fuel is still available, or there are almost no cars left that require leaded, a number of "snake oil" remedies are on the market at greatly inflated prices. As with most automotive additives, avoid any that claim to increase power output, or improve the longevity of anything other than exhaust valves. Have unleaded valve seats installed in your cylinder head. This will typically cost $US40 or UKP20 per seat, give or take 50% (there are four exhaust valve seats). Many cylinder head shops will insist on reconditioning the head to some degree, such as fitting new exhaust valves and guides and replacing any excessively worn parts, plus a likely charge for cleaning and crack testing. If your cylinder head is reasonably old, this is a good idea and will give the highest-quality results. Take your chances with unleaded fuel. There is much anecdotal evidence of Mini owners successfully running on unleaded fuel for many years without trouble in the USA, Canada, continental Europe and New Zealand. (There is also a much smaller amount of anecdotal evidence of severe wear on currently available unleaded fuel in the UK). Valve seats should be expected to wear faster than with leaded fuel, but if your engine has more than 100,000kms on it, the engine itself is likely to fail long before the exhaust valve seats. Purchase a new, unleaded cylinder head. These are available for all A-series engine sizes, though not necessarily to the spec of the original on your engine. A Mini specialist or cylinder head shop can adapt the head to appropriate specification (valve size and combustion chamber volumes) if it is not suitable "off the shelf". Which option is for you? If you have a standard Mini 850-1275cc, use of reputable brand fuel additives is recommended for low-mileage or high-value cars. If your car is a "budget banger" or is soon to receive a new or reconditioned engine, it is a personal choice. If your car has a "big valve" modified cylinder head, it is not possible to use exhaust valve seat inserts, so use of additive is recommended. If you experience "pinging" noises (detonation) when using unleaded (often when the engine is working hard), the additive can alleviate this problem. Having valve seat inserts installed is only necessary if/when an exhaust valve fails - there is no need to do it as a preventative measure. You may wish to run without additives until this happens. I can speak for 50,000kms having been run up using unleaded on a tired old 998cc engine that had 120,000kms on the clock when unleaded was introduced in New Zealand. The bearings failed and the engine was junked. The valve seats were in "barely functional" condition. This is not unusual for an A-series engine at 170,000kms regardless of the fuel it has run on. I have also put at least 10,000kms on three other tired a-series engines with no valve seat problems on visual inspection. Purchasing a new cylinder is also only necessary when the old head fails. "Unleaded" cylinder heads can be modified to "big valve" spec and safely run on unleaded fuel. Most Mini specialists can supply their modified stage 2/3/4... cylinder heads based on an "unleaded" cylinder head casting, so if you are considering a performance upgrade, go for the "unleaded" version. The second problem with "unleaded" fuel is the downgrading of octane rating and fuel quality that often accompanies its introduction. Modern engines with electronic fuel injection are able to get good performance from inferior fuel by running the engine at air/fuel ratios and ignition timings that are barely on the right side of the fine line between safe operation and severe engine damage, and adjust fuel and ignition settings to accomodate varying petrol quality. Mini engines are not capable of this fine control. Since they are calibrated to expect a higher-octane fuel than unleaded, they are liable to suffer from detonation, resulting in an audible pinging sound from the engine. If this is allowed to continue, severe engine damage will result. To alleviate this, lead substitute additives can be used (as they contain agents to raise the octane of the fuel back within the range the engine is expecting), and/or the ignition timing can be retarded, meaning the air/fuel mixture is ignited later than usual. The lower-quality fuel may also include excessive levels of aromatic compounds, in particular toluene and xylene. When unleaded fuel was introduced in New Zealand, some old cars (including mine) suffered from failure of rubber parts, which swelled up and disintegrated in the presence of such high concentrations of aromatics in the fuel. Fortunately, the damage in my case was confined to a seal in the carburettor - cheap and easy to fix. If, under switching to unleaded, you smell petrol in the car's interior or see petrol dripping from underneath the fuel tank or the fuel lines in the engine bay, don't drive the car until all affected parts have been repaired. The oil companies lowered the proportion of aromatics in the fuel in response to media and government pressure - they had been attempting to sell a fuel of far worse quality than is available in most countries - it is less likely that this situation would happen in the UK or USA, or other relatively large country. Finally, the issue of "bolt in" solutions, where companies install a device in the fuel line that is supposed to chemically alter the fuel to make it safe for use in older vehicles. The sales pitches usually include claims of tests by unnamed "independent laboratories," and pseudo-scientific claims of magnetically realigning the fuel, or releasing small quantities of tin or lead into the fuel over time, not to mention anecdotal claims of increased fuel economy and even acceleration and power. One of these devices, marketed in New Zealand under the FuelStar brandname, failed to meet Australian government standards for the prevention of valve seat recession under independent tests similar to the one described above for Valvemaster (which passed). Ironically, the cost of having valve seat inserts fitted, or even buying a new cylinder head, are around the same price (perhaps less) than the cost of having one of these devices installed. Back to Top Unleaded petrol - is my Mini designed for it? The change over to unleaded-compatible cylinder heads occurred in 1989. If your car is 998cc, engine numbers starting with 99H/D81, 99H/E, 99H/F, 99H/G, LBB10089 or LBB10175 are lead free. If your car is a 1275cc Rover Mini or Rover Mini Cooper (1990 on), it is designed to run on unleaded. What do HS2/HS4/HIF44/etc mean? They are model numbers of SU (Skinners Union) carburettors, the type of carburettor fitted to all Minis until the arrival of fuel injection in the 1990s. HS2/4/6/8 - the number represents the size of the carburettor, in eights of an inch plus one inch. So HS2 is 1.25 inch, HS4 is 1.5 inch, HS6 is 1.76 inch and HS8 is 2 inch. HIF carburettors are a more recent design than HS carburettors. HIF stands for Horizontal Integral Float, meaning that the float bowl is integrated into the carb body instead of being to one side as on the HS carburettors. This counteracts fuel starvation during hard cornering. These carburettors also have a few other features to make fuel delivery more accurate provide compatibility with turbochargers. HIF carburettors are found on many British cars from the 1970's onwards including the Metro. HIF carburettors may be specified as per HS carburettors, i.e. HIF4, HIF6. These carburettors are more commonly named HIF38 or HIF44, which are the equivalent sizes in millimeters. Which carburettor is best for me (Weber/SU/etc?) Which carburettor is best for you? This subject is fairly complex and probably no-one will ever cover it better than David Vizard in Tuning British Leyland's A-Series Engine - order a copy now. If you have a specific engine setup and want to know which carb is best, go to the message board and ask. Some rules of thumb: HS2 - Mini 850/1000, for originality only. HS4/HIF38 - Mini 850 to 1275. HS6/HIF44 - Mini 1275+ and modified engines. HS8 - put it back on the Rolls Royce/Volvo/V8 you got it from. Twin HS2 - for originality only. Twin HS4 - Mini 1275+ and modified engines. Weber carbs - race applications or novelty value. Some downdraft carbs will fit with no body mods - not a bad idea if you have one lying around. Some people like tuning Webers better than they like tuning SUs. Nikki/Amal/Reece/Fish/etc - only needed for retro and novelty applications such as 8 port heads. Twin SU carbs offer no real advantage over a single HS6/HIF44, which is also easier to set up - the engine only draws air through one carb at a time. Weber carbs don't give you terrible fuel consumption unless they are incorrectly set up. A carb that is too big for your engine will reduce fuel efficiency and power. Back to Top Gearbox Differential Tips When changing differential ratios, the pinion gear need not be changed if the ratio is altered between 3.647 and 3.765, between 4.133, 4.267, or 4.33 (A-series), or between 3.105 and 3.211 (A-plus). The part numbers of the pinion gears are identical within these ranges. Instruments Changing the speedometer cable Ensure that the engine is cool. Follow the cable down from the back of the instrument cluster to the top of the gear box. Alternatively, remove the right-hand road wheel and try to reach the end of the cable from below the gearbox. Undo the knurled nut which should be hand-tight. If access is tight, remove the radiator. If the nut is too tight, wear leather gloves for better grip. If the nut is still too tight, use a 7/16 socket to undo the speedometer gear assembly which can then be removed from the gearbox. To prevent future problems, clean the speedometer cable nut threads and the fitting threads, lubricate with antisieze grease and tighten to hand-tight. Ensure there are no sharp bends or kinks in the new cable. Cables vary in length depending on the year of car and whether it is RHD or LHD - specify when ordering a new cable, or measure your present cable and order one the same length. Back to Top Fuel gauge reading incorrect If the gauge always reads full, the green/black sender wire may be shorted to earth or the sender in the tank may have failed. If the gauge always reads empty, the green/back sender wire may have become open circuit. Check voltage regulator. Check all electrical connections between gauge and sender for short circuits between each wire, between each wire and earth, and for open-circuit. Disconnect the sender unit and check the resistance across its' terminal and earth. This should be in the low to hundreds of ohms range, and not open-circuit or short-circuit. To check the gauge, remove the wire from the sender and connect it to earth - the gauge should move to full scale. Fuel gauge and temperature gauge reading incorrect If both the fuel gauge and water temperature gauges read incorrectly, the voltage regulator should be replaced. Temperature gauge reads high If the temperature gauge reads high but the car is not overheating: Ensure the gauge is connected to the voltage regulator (approx. 10 Volts) and not the 12 Volt supply. If the engine has been swapped with one from another car (e.g. Allegro, Metro) the temperature sender may be incorrect - replace with a temperature sender from a Mini cylinder head. Suspension Changing inner driveshaft joints There are three types of inner driveshaft joint: rubber cross (early Minis), Hardy Spicer (Cooper/Cooper S) and CV type (all minis '70s on). Rubber cross type may be more suitable in types of racing that impose strong shock loads on the drive train (e.g. autotesting). To change between joint types, re-build the diff with the output shafts of the desired joint type. The output shafts on the rubber cross diffs had a thread on the end that is used to hold the cross-joint yokes in place, the CV ones are shorter with a circlip on the end to secure the pot joint. Back to Top Checking/setting toe-in (by Neil Williams) You need a rod that extends across the width of the car + a bit. It needs to have a "point" on one end that does not move. (I bolted a skinny bolt through a piece of 1/2" square tube for mine and ground the tip of the bolt to a point.) On the other end you need to have a point that will slide over the rod. (I used a slightly larger piece of rod and another ground down bolt. With the moving end you need a wing nut type on it so that you can tighten it up once you have your measurements) It needs to look like this. Fixed Point 1/2"rod Moving point !-----------------------------------!--- Once you have made the rod the process goes something like this: Find a friend Find a level piece of ground that you can roll the mini along. Put car in neutral on the level ground. Get your friend to hold one end of the rod and you hold the other. Put the rod across the back of the front tyres and make a slight scratch in the tread of the tyres with the points of the rod on each side. Roll the car forward until the scratches that you have made are 180 degrees from their original position. (You will not get exactly 180 degrees on all cars) Put the rod up onto the scratch on one side and look at the distance between the point and the scratch on the other side tyre. This will be your toe in/out. Adjust your tie-rod sleeves accordingly and repeat process until the correct settings are achieved. Back to Top Disc brake hub reconditioning Jack up the car and remove the road wheel. Remove split pin from end of cv joint and undo the hub nut. Remove brake caliper (2 bolts at back) and tie up out of the way. Pull away the disc and drive flange as a complete item. Split top & bottom swivels and track rod end and remove hub assembly. Ccheck the CV joint shaft is not badly scored or worn, causing play. Take seals out of either side of hub and remove loose bearing races. Hold hub in a vice and drift out bearingraces using a drift on the back side of the races working around them to get races out square. Drift new races in with spacer in middle if in kit - drift races in square using piece of pipe to avoid damage. Pack bearings with grease. Replace hub, inserting CV/stub axle through middle of hub. Reconnect swivels and track rod joints. Place disc/flange assemble onto end of cv joint, refit caliper, push back of cv outwards to take up slack at back. Fit spacer washer on then the big nut (apply and hold brakes on) torque nut to 150 lb/ft, remove nut, remove washer, replace with split collar. The washer procedure ensures the bearing is compressed to stop premature loosening. Replace nut, torque to 150lb/ft then NOT USING THE TORQUE WRENCH use a long bar to turn the nut until the slot lines up with the hole- fit the NEW split pin. Tools required: A flat washer to take the place of the split collar under the driveshaft nut, a drift to remove the races in the hub, a ball joint splitter and a torque wrench. Front hub nut keeps coming loose This is usually experienced with disc brakes where the hub nut is required to provide preload for the taper roller bearings. Ensure the nut is tightened to the correct torque figure (60 lbft for drums and Cooper 7 inch, 150 lbfts for discs), the split pin is inserted and the nut is tightened until the split pin holes line up, not loosened. Check the threads of the hub nut and stub axle for damage. Wheel bearings are excessively worn and must be replaced. Replacing worn/broken suspension parts Always replace suspension parts (such as shock absorbers and tyres) in pairs (i.e. both sides of the car) to keep the handling of the car from becoming erratic or unpredictable. Back to Top Reassembling ball joints Sometimes when you try to reattach the hub to the suspension arms, the whole ball-joint turns so you can't re-tighten the nut. It helps to have lubricant on the nut threads but not on the taper; then you can use a bar to force the taper *hard* into the tapered hole on the suspension member while you tighten the nut. Splitting ball joints When splitting a ball joint using a splitter, hammer or other means, leave the retaining nut on the thread of the joint, done up until it is parallel to or slightly above the top of the thread, so it absorbs any damage. Otherwise, the threads may be damaged making it impossible to do the retaining nut up. Suspension cone compression tips The risk of breaking a cone compressor or stripping the thread of the nuts in the front rubber cones can be reduced by running a thread chaser through the nut until it is clean, and by using grease on the thread chaser and the cone compressor. Early cars have imperial-thread rubber cone nuts, later cars have metric - using the wrong cone compressor will strip the thread in the nut. Back to Top