Period Reports

Tuning Your MG

©July 1952 issue of Auto Speed and Sport

Tuning your MG Remove the spark plugs and clean them with a wire brush. Check them carefully for cracked porcelain and badly pitted electrodes. Replacement of the plugs cannot be determined by the mileage of the car alone and the old standard of 10,000 miles is no longer valid. Plugs should he checked frequently and replaced whenever they show signs of wear. Set the plug gap by bending the side electrode, never the center. The correct gap is between .020 and .022 inches PHOTOS BY JACK CAMPBELL THE TUNING of a sports car is an essential element of owning a sports car. Unless the engine is maintained in top condition, many of the driving pleasures common to this type of car are lost to the motorist. The small displacement engine of the MG, famous for its reliability, can be as disappointing when out of tune as it can be satisfying when running properly. On these pages you will find a few simple procedures designed to aid the MG owner in tuning his car. These are the methods used by one of Southern California's best MG mechanics, Harvey Mayer, who recently opened his new shop in Costa Mesa. You may or may not agree with his basic suggestions, but we feel certain that these are easy-to-follow tuning tips for the man or woman who tunes his or her own MG and wants to experience the pleasure of driving a perfectly adjusted car at all times.

A handy gimmick for the home mechanic is the hood stick made from an old broom handle. Notched at one end to fit the bracket on the center hood binge and wedge-shaped at the other to fit the bracket on the front hood latch, the stick is short enough to be carried around in the tool compartment and will prevent you from banging your head on the hood side when bent over an engine A FEW BASIC HINTS THAT MAY HELP YOUR MG RUN BETTER Remove the distributor by cutting the lockwire and unscrewing the large bolt at the base of the distributor and the wire from the coil Points that are only slightly worn may be resurfaced, but do not use a file as it will leave a rough surface susceptible to pitting and burning. A fine sharpening stone should he placed in a vise and the points resurfaced in the manner illustrated. Be careful to hold the points perfectly flat during this operation Remove the points by releasing the two screws and the one attaching nut. Inspect the points for excessive burning and/or deep pits. If the points are badly burned, no attempt should he made to resurface them, but new points should he installed

After the points are re assembled, they must be checked to make sure they meet perfectly flat and even when closed. A certain amount of adjustment may be obtained by bending the stationary point, but use caution and do not mar the point surface. Points are adjusted when fully open and the correct setting is .010 to 012 inches. When this is completed, scrape (with a knife blade) the burnt deposits from the contact points inside the distributor cap and on the rotor contact. With a light machine oil, lubricate the advance mechanism in the base of the distributor and add a few drops in the hole at the top of the distributor cam When the distributor is replaced, it must be, re-timed. To do this, turn the engine over slowly until the, No. 1 piston is on the compression stroke. This will be indicated by the alignment of the marker on the front timing chain case with the small notch on the crankshaft pulley. At the same time; remove the valve cover and make certain that the valves of No. 1 cylinder are completely closed. This will determine the compression stroke. Next, install the distributor so that the rotor is pointing to the No. 1 spark plug wire on the distributor cap. Loosen the clamp bolt on the side of the distributor and revolve the entire unit until the points are just starting to open. Start the engine and set the throttle at 1200 rpm. Revolve the distributor slowly in a clockwise direction until the engine starts to buck. Turn it back slightly until the engine smooths out and tighten the clamp bolt While the engine is still warm adjust the valve tappet setting to .019 inches. Care must be taken during this process to see that the valve is completely closed and the camshaft in the proper position. Here is an easy way to determine this. Start with No. 8 valve and slowly turn the engine over until you are sure that No. 8 valve is fully open. By using a little mental arithmetic, subtract the number of the open valve from the figure nine. This is the number to adjust. Keep repeating this process, always subtracting the number of the open valve from the figure nine and adjusting the resulting number

Remove the air cleaner and manifold plus the two screws which hold the carburetor damper assembly. Remove the piston and cylinder very carefully as shown in the photo to avoid bending the needle   Wash the piston and cylinder thoroughly. A good lacquer thinner is excellent for this job as it will dissolve all the gum deposits on the piston. It will also clean the red gas stains from carburetor bowls and throttle body   To fit properly in the jet, the piston needle must be absolutely straight. This may be checked by clamping the piston rod in a drill press while a straight edge is held next to the needle. Revolve drill press slowly by hand Reassemble the float and bowl cover and damper assembly. A few drops of a very light machine oil should be put in the hollow piston shaft and the cap replaced. Use the oil sparingly as too muck oil is just as bad as not enough. Lift the piston with a finger and make sure it drops freely to the bottom of its travel. If it sticks, loosen the large nut directly below and revolve the brass jet assembly slowly until the piston drops freely. Tighten the nut and check the drop again. Further adjustment of the carburetors is far too critical a procedure to be discussed in this article, and it is suggested that the manual be consulted for this operation   Remove the top of the float chamber bowl and slide the brass float up the shaft to clean out the bottom of the bowl. Check the float level setting by placing a 3/8-inch test bar under the forked lever. To be properly adjusted for normal driving, the prongs of the lever should just rest on the bar. The shank of a 3/8 drill may be used for a bar

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