Buying an MGB

By Graeme Adams

The MGB forms the backbone of our club for many easily seen reasons. Production numbers are large, cars and spares are available at reasonable cost, they are easy to work on and modern enough for every day use.

Now just what have you bought? Most now know that the body is the expensive part to fix, rust being the hidden problem. Sports cars this old are not ‘standard’ any longer. All have been modified by their owners for better performance or simply by the process of running repairs.

Some of the changes made to them are often quite superficial like small steering wheels while others are well hidden. Just what is the compression ratio? A quick inspection gives away wheel rim width but tells you nothing about the cam grind, so it’s a little hard to tell just what you have at hand.

I should point out that there are any number of good books that will give you all the information that you will need to buy or fix your car, but the following may just help a little.

To get past the roadworthy, the car has to have shock absorbers that are in at least fair condition. The ‘B’ has leaver arms that can be long lived or can die in just a matter of months. At the front end the shock absorber forms the top arm of the suspension and is not generally replaced with a telescopic unit. At the rear end telescopics are often fitted as they are almost a fit and forget item. I am not sure that they are any better than good leaver arms, but leaver arms don’t seem to stay good for long.

As produced and after all this time the car body rolls too much leaving the road wheels at odd angles. This can be minimised by the fitting of a stiffer front anti-roll bar. Use the type that does away with the old connecting rods as they are a problem.

Along with a stiffer anti-roll bar, the biggest single improvement that can be made is the fitting of 60 profile tyres. This does compromise ride height a little but not enough to be a problem. It does however make cars without overdrive a bit busy in top gear. I am not saying that this is hurting anything other than the pleasure of open road motoring via your ears.

The old saying goes that the brakes stop the wheels and the tyre stops the car. Think about it, it’s true. While many cars are fitted with wide wheels, the performance gain is small compared with the gain made by 60 profile tyres on the ‘standard’ 4 1/2" wide wire wheel rim, and at considerably less cost.

Front springs seem to stand the test of time but the cart springs at the other end are another matter. These can be rebuilt generally with a new 3/4 main leaf added. This eliminates back end sag and axel trap that is common with old springs. A little care is needed to get the correct ride height.

It goes almost without saying that all the flexible brushes at both ends should be considered when any work is being done on suspension. They may have been there from new. The home mechanic can grease all the points, mainly front end, to keep problems to a minimum if not eliminate them all together.

Any strange noises or vibrations will let you know when the gearbox or differential is looking for a little help. To get at the gearbox or clutch, it’s an engine out job. But first check that the tail shaft bolts are tight and the universals are in good order. Any play in this area will show up as vibrations through the car.

Brakes, wheels and splines for wire wheel cars are straightforward and covered in general reading. One small tip would be to have the back brake shoes set up to suit the drums. This is important if in the end you want the handbrake to be just right and gain maximum braking performance.

Again the engine is well covered in many places and should be considered in detail when work is necessary. Carburation condition is important, while the Lucas distributor is hard to get bits for and is more often than not replaced by a Bosh unit set up to suit the engine. While it is not real cheap, it’s often a large step forward.

If you have to take the head off for any reason, good gains can be made at a cost. Remember that an old engine can suffer from a ‘hot’ head. If the head is off then hardened valve seats should be considered, then unleaded fuel can be used without valve problems. The new high octane unleaded fuels allow the use of increased compression ratios for engines in sound condition. You need to obtain expert advice if you are to use compression ratios much above 9.5 to 1.

A car modified as outlined will drive like a "true" sports car, handling well without being too harsh. It will not like the rough stuff much but then they were never designed for that in the first place. A car set up this way will be very rewarding to drive. If you require help there are a number of members in the B Register who are at Club meetings or only a phone call away.

Graeme Adams

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