MGA-MGB, Midget

In principle there are three types of electronic ignition:   Points replacement module:  this substitutes an electronic switch for the mechanical points.  It has two big advantages over the [...]

Note:  Midgets and late rubber bumper B’s used rods rather than cables in places.  In this note, please read handbrake cable to be handbrake rod where relevant. If the handbrake lever is [...]

Midget front wheel bearings are of the angular contact type.  They are non-adjustable and are assembled with a solid spacer between the inner and outer bearings so that both are locked on to the [...]

With modern cars having engine computers to do all the tricky stuff, the operation of the choke is something that many new owners of classics are not familiar with.  Under use of the choke will [...]

If a tyre of a different size or aspect ratio is fitted, this will affect the speedo. To check the effect of the tyres on the speedo, measure the rolling radius of the front tyre and rear tyre. [...]

Paul’s tips on how to go about it! (Part 1) NOTE: While the following is written mainly around the MGB, it also applies equally to the MGA and Midget other than remembering that Midgets are a [...]

I had a chance to try out the superchip with the accelerometer today, on our VVC engined Midget. The engine is standard MGF apart from a 55mm throttle body & larger exhaust.   The superchip [...]

If using the original Rover engine computer (MEMS) in a conversion, it may be necessary to address the computer’s immobilser.  The MEMS security system searches for a coded signal from the [...]

Check that the immobiliser (if fitted) is responding to your key fob transmitter by checking that the alarm indicator light on the dash has stopped flashing. If not, most commonly the fob may be [...]

Paul Walbran Motors:   Wiring notes, K series engine & ECU intalled into MG Midget (This was done for a VVC, but is generally applicable to non-VVC which is the same except for the [...]

Soft tops stretch in use, so hood manufacturers and fitters set them up to be tight initially – if they didn’t the hood would turn into an ugly floppy bag of a thing once it had been [...]

Windscreen glazing seals can sometimes appear to be too short or too long. This happens because the seal gets slightly compressed or stretched during the fitting process. If this happens, start [...]

Fitting a convertible windscreen is a difficult job, but if you are reasonably handy you should be able to do it. All it requires is a bit of care, a lot of patience, and an average level of DIY [...]

If your window regulator problem is the usual stripped drive problem, you can fit the regulator drive head from any contemporary BMC saloon as they all used the same basic unit with different [...]

Indicator won’t work at all Check the fuses The simple way to this in pre-1980 MG’s is see if the wipers, tacho and fuel gauge are still working, as they all run off the same fuse. Hazard Switch [...]

When driving on gravel you don’t get the weight transfer you get when braking on seal, and when rallying you also want a bit of rear bias to help kick the car sideways going into corners.  [...]

Midget: The Midget is relatively simpler than the B.  At the front end, the chassis outrigger brackets which form the inner mounting for the wishbones need to be changed.  Alternatively, the [...]

A number of factors, including tyre pressure, wear and wheel alignment, can affect the steering.  In addition to these, for those used to driving saloon cars and not familiar with MG’s, the [...]

The main thing to check for if contemplating repairing leaf springs is around the end of each leaf. Have a good look at the leaf above to see if it has been worn by the end of the leaf below it. [...]

To get the right position of the bottom mount hole, measure the clearance between the bump stop and where it hits the body at full bounce. Add 1/2″ to allow for bump stop compression. (Some [...]

When full power is applied to the driving wheels, the axle experiences a reaction torque which tries to rotate it in the opposite direction from the wheels.   A tramp bar is a device which [...]

Rubber bushes which incorporate steel sleeves in the inner hole (crush tubes) are frequently seized between the crush tube and their supporting pin, making removal difficult. Examples are the [...]

Midgets with the square wheel arch at the rear (all of them apart from 73-74 models) are very tight for clearance on wheels and tyres, so when fitting alloys it is important that you make the [...]

Books have been written on this, so I’ll try to be brief: A car should track around a corner along an arc with its centre at the meeting point of the rear wheel and front wheel axes. The more the [...]

Sometimes wire wheels can be a problem to get balanced. Here are a few tips to try and solve it: Check how the balancing machine locates the wheels. It should locate on the taper on the inside of [...]

What it contains: 1 pr Bilstein shocks Upper mounting bracket Upper inner fulcrum block and bushes Upper wishbone arms and fulcrum shaft Modified upper spring locating cup Modified bottom spring [...]

When do you need to upgrade your brakes? For normal – even exuberant – road use, the standard brakes are fine, especially if fitted with uprated pads and linings. My key reference [...]

Safety warning The MGB and Midget rear wheel cylinders are part of a range identical in design apart from the bore size, which ranges from 5/8 to 7/8 (I think I have seen 15/16 too) in 1/16 [...]

In New Zealand as we don’t have a salt-induced corrosion problem from the outside as they do in the UK, so a stainless system hasn’t quite the same imperative here. However, stainless [...]

The workings of an extractor are frequently misunderstood and misrepresented, so herewith a bit of explanation. For reading material, one of the best books I’ve found on the topic remains [...]

The USA spec fuel cap fitted to many MGB’s & Midgets was unvented and as a result sometimes there is a big suck of air when you undo the fuel cap. – to such an extent that the [...]

The original SU pump is very reliable for about 12 – 15 years. Once it starts to falter, overhaul it and it will be good for another 12 – 15 years. The SU pump only ever had one [...]

Questions are often asked about how well the Midget rear axle can cope with additional power.  The answer is that it depends on which part of the rear axle you are referring to! Our testing [...]

Halfshafts require good ultimate strength – which will depend on the both type of steel used and the design. The material strength is a similar issue to bolts: Mild steel bolts are like [...]

Care needed! When replacing the pinion oil seal you need to be aware that you could disturb the settings on the diff of some models. The reason for this is that the pinion bearings are set up [...]

Clutch drag is when the car will not engage gear properly without grinding the gears, especially in reverse. Generally, this occurs because the pressure plate is not retracting enough to clear [...]

It is not necessary to remove the brake backplate and seal housing from the axle assembly – simply withdraw the inner cone (on which the hub mounts and the seal runs) over the halfshaft. Do [...]

What does a Limited Slip Differential do? An LSD is installed to maximise wheel traction. These benefits are seen most readily in competition, particularly where the car is attempting to [...]

Sometimes doubt arises as to the diff ratio currently fitted to a car, as a significant number of them have had their diff ratios changed over the years.  Reasons include Deliberate modification [...]

Note: In addition to the changes below, cars with 3 bearing engines have a much smaller crankshaft spigot bush (5/8″ against 7/8″). As far as I’m aware, the only way around this [...]

Currently, the needles in the AAU3052 bearings are .004” undersized, which will result in incorrect meshing of the gears.  An alternative is to use needle roller 8G2404 in this application.  [...]

Introduction An overdrive is a two speed, electrically activated, supplementary gearbox which is attached to the rear of the main gearbox.  It was a popular period option which easily converted [...]

The page on valve clearances in the tuning section refers BMC cams. My comments above also assumed normal roadwork, not competition. Other profiles have the ramps in different positions at [...]

To ascertain what type of camshaft you are running  (or at least get a feel for it) Camshafts can be identified by the opening and closing points of the valves, in conjunction with the amount of [...]

If the engine has been modified, its requirements for ignition timing will probably be different from standard. Also, the distributor itself may have been modified. What I describe below is a [...]

Run-on is a term used to describe what happens when the key is turned off and the engine continues to run somewhat erratically for a second or two, or even quite some time.  Run-on causes high [...]

(Applies to any engine, but the B series is particularly prone to it). Combustion problems caused by erratic burning and/or detonation of fuel rather than controlled and even burning shorten [...]

Forget the old myth that they are hard to keep tuned.  Twin carburettors have an unjustified reputation for being hard to keep in tune. It’s origins lie in the bad practice of fiddling with [...]

The vacuum unit works to advance the spark on part throttle in order to improve efficiency and fuel economy when cruising/at steady speed. At full throttle the manifold vacuum disappears and so [...]

Maintaining the correct valve clearance is important to prevent premature valve train wear.  Too tight and there is a risk that the valves won’t seat properly and burn out, too loose and [...]

The most common cause of combustion problems such as pinking in MG engines is not fuel as usually assumed (provided the engine is running on minimum 95 octane), but distributors not performing to [...]

The following notes are intended to supplement the information on how to set ignition timing (by either method) which is found in most good workshop manuals, with particular reference to how to [...]

All pre-electronic MG engines are easy to tune and hold no great mysteries, so are easy for owners who want to do their own maintenance to tackle if they go about it methodically and in the right [...]

If you have a problem with carburettors touching/denting the bonnet,or engine mounts breaking under competition use then read on … On our Midgets we have put a restraint on the engine mount [...]

If your engine won’t start easily when hot, and has good fuel delivery and good spark, it may be because heat soak is making the fuel expand and rise enough to dribble out the jet and flood [...]

If your engine has been running fine and suddenly dies and will not fire at all while cranking on the starter, check: Fuel – assuming you have some in the tank! Remove a fuel line from one [...]

Both A series (except the 1275) and B series engines had cover plates on the side of the block providing easy access to the cam followers.   On the 1275 (except the early Cooper S blocks) the [...]

Excessive tappet noise is an indication that something needs attending to.   Even the B series engine, renowned for tappet noise, is quite quiet in the valve gear with newly reground cam and [...]

It is often difficult to determine whether valve seat inserts have been fitted before, when viewed only from the chamber, – the original machining usually left a pattern which is not to [...]

I often get asked what is the best way to deal with this. The options are: Additives added to the tank when you top-up with fuel In-line tin-based canisters Stainless valve seat inserts. [...]

An engine freshen-up is a term that means different things to different people. In the context of the following I have taken it to be replacing the rings and bearing shells and attending to other [...]

There are two faults which show up in the breather systems of Midgets and MGBs which cause dramatic oil consumption and lots of blue smoke, even with a reconditioned engine.  Quite a number of [...]

MGA, MGB 3 main bearing, and MGB 5 main bearing engines all had different water pumps.  MGB 5 bearing engines also had two types of water pump, differing in their length. When ordering [...]

All 1800cc heads have the number 18 embossed on the top of the head next to the rear stud (on the spark plug side of it). 1600 heads have a 16, most (all?) 1500 heads had nothing there. On the [...]

Bolt head markings show how strong the bolt is. Original bolts on MGB and earlier MGs carried markings on the bolt head, the most common of which were ‘R’, ‘S’ or ‘T’. R is a basic grade of bolt [...]

If a tyre of a different size or aspect ratio is fitted, this will affect the speedo. To check the effect of the tyres on the speedo, measure the rolling radius of the front tyre and rear tyre. [...]

In NZ, there is always vagueness as to the exact model when looking at date of first registration due to the shipping time as well as the other lags between manufacture and sale. I’ve never [...]

For pre-emptive maintenance, classic MG’s are fairly basic cars and simple to maintain by today’s standards.  The long term health of the car can be easily looked after on a day-to-day [...]

      A car which has its registration lapsed for more than a year is de-registered by NZTA.  To return it to the road, it has to undergo the same compliance process as a newly imported vehicle, [...]

Look before you leap!   If you are thinking of importing a car to NZ, here are some things to be aware of:         To be registered in New Zealand, the car will have to undergo a compliance [...]

       We offer free pre-purchase checks which are high level rather than detailed checks of the key problem areas of the body, engine condition and the general feel of whether the car drives as [...]