MODIFIED STOCK CAR RACING – America’s New Sport of Thrills (Dec, 1933)
MODIFIED STOCK CAR RACING – America’s New Sport of Thrills
Modified stock car racing is taking the country by storm, and offering young speed demons a chance to win handsome prizes. Here an old head at the game tells you how you can strip down your car and qualify for these spectacular events.
by ROBERT M. ROOF
MODIFIED stock car races are now being featured on almost every dirt track race in the country. These spectacular events are winning a fast-growing popularity, attracting thousands and thousands of people on the look-out for some new thrill.
As this sport increases in popularity, the chances for steel-nerved drivers to win huge purses also become more numerous. State and county fairs most always stage a stock car raceâ€”and it is here that budding young speed demons get a chance to break into the racing game.
The races are most generally run on a percentage basis, forty per cent of the gate receipts being appropriated as prizes. When the weather is hot and clear the purses are very attractive, for we find that the hotter the day the faster these stock cars will run and this in turn attracts more people to the track.
Every owner of these stock car racers thinks he has the speediest of them all, but when he gets to the dirt track he finds that it is a battle royal. After the smoke has cleared from the track and he realizes what speed the other cars have his first thought is, “How can I make this Alligator (a term used for a slow car) run faster.”
From experience we have learned that the following stock cars are best suited for these modified slock car races. Model A Fords, Model T Fords, V8 Fords, four and six cylinder Chevrolets, Plymouths, DeSoto and Studebaker, Pontiacs are also adapted for stock car racing.
Modified stock car racing gives the amateur driver an opportunity to demonstrate his driving ability. It is from these stock car races that the owners of big priced racing cars pick their drivers, for they are not afraid to trust their cars with them.
Two ten mile sprints and a feature race, generally a twenty or thirty mile event, meet all the demands of the racing fans.
The stock cars must qualify for their positions in the race on the morning of the race day. It is a general rule that the ten fastest cars are allowed in the first event, and the slower cars in the second or consolation race.
The winning cars in the first event are not permitted to race in the consolation event. This gives the slower cars a chance to win some money to defray traveling expenses.
During these two ten mile races, a number of cars will drop out because of some mechanical trouble, which generally leaves about sixteen cars at the starting line for the last and feature event.
In addition to these three regular races there is usually some stunt race. The photo shows two of these stock cars in a blind- fold race. There is some trick about this blind-fold race. On one occasion as the writer was standing on the track, one of these drivers started directly towards him, but swerved his car just in time, but it did give the writer a cold chill.
These stock car races are conducted in a first class manner. All owners and drivers are required to sign a track release against damages of all character.
There are certain signal flags used in these races. The white flag is used to start the race, the green flag means you are starting your last lap, the checkered flag is the one all the boys look for, their cherished hope, a winner.
When starting the race the drivers are lined up in the position they qualified. The fastest qualifying car is known as the pole car. The pole car leads the pack around until they are lined up for a flying start. This is the time for the white flag and the race is on.
The first lap is the most dangerous of all as each driver wants to get into the turn first. After this lap they scatter out and this releases the nerve tension on the drivers.
A good driver has a clear eye, quick mind and plenty of lead in the foot. A good driver will always give a fellow in a jam a chance to get out. This always appeals to the fans. A dirty driver never gets very far in racing.
Stripping the Car for Action While building these modified stock car racers one must be like a doctor with a number of patients each with a different disease. Each car requires separate and individual attention. Take the Model A Ford, which has been winning most of these events. This is how we start.
Remove all the fenders, headlights, windshields, top and any other part that would cause any wind resistance. Take out the front and rear springs and have them straightened. Two inches of spring clearance is sufficient.
It is best to use double acting oversize shock absorber in front and rear. These keep the car on the track and make it fast. The 1928 or ’29 Model A Ford is preferred.
New Ford V8 Is Fast Racer The new V8 Ford wheels and tires fit these models and make a strong combination. The V8 Ford gear ratio, which is four and one ninth to one, is what the boys are using on the one-half mile tracks and they would use four and one-third to one if they could secure them.
When reconstructing the engine it is best to remove it from the chassis and take it to a machine shop. Bore out the valve ports on the top and side to one and nine-sixteenth inches in diameter, and only five- eighths of an inch deep. These dimensions cannot be exceeded, as you would cut into the water jacket. A thirty degree valve seat reamer is used to make the new valve seats. The valves which are used are special for racing, carrying compound springs with the liberty locks and keepers for retaining the valve springs.
A valve clearance of twenty-thousandths of an inch is allowed. A special racing camshaft which gives the valves a higher and faster lift is used to secure a high R. P. M. Steel timing gears are used with this valve and camshaft assembly.
Some of the boys are using pressure oiling systems on the main bearings and splash systems on the connecting rods.
Special Racing Pistons Required Solid skirt nickel aluminum racing pistons are necessary to carry these extreme high compressions. The top of these pistons should come one-thirty-second of an inch from the top of the block when on top dead center.
The cylinder heads used on these Fords are known as the flat head type, the compression ratio being between seven and eight to one.
Carburetion and manifolding are very important factors in getting the R. P. M. The photo shows type of oversize manifold with velocity pipe and the racing Winfield downdraft carburetor, the same type carburetor used on the winning cars at the Indianapolis Motor Speedway.
Ignition Equipment The final equipment is the ignition. There are two different types, battery and magneto system. Every driver knows that the magneto system is the faster. The photo shows how the magneto is attached to the block. It carries its own water and oil pump, and does not carry a fan pulley. This eliminates the fan and belt. No fan is used on these fast stock cars.
The second type is the double breaker Mallory distributor. In connection with the distributor, a special racing coil is used which has a double winding with thirty thousand turns. This makes a very hot and fast spark. It requires the special racing metric spark plug to withstand the compression and spark.
All cars described in this article use a special fuel dope in their gasoline. The flying mass consists of crankshaft, connecting rods, pistons and pins, flywheels. All these must be kept to the lowest possible weight. For this reason we use a Lynite Flywheel with the driving face lined with steel giving it a weight of about ten pounds. This gives the motor quick acceleration and deceleration.
Converting Chev Six Into Racer For the Chevrolet Six, we find the following parts used to make them fast for stock car racing. The standard Chevrolet cylinder head is used with the following changes. We plane off 3/16 inch from the head and bore out the intake and exhaust ports as large as possible and install the new racing valve with 30 degree seat with compound springs and keepers. Also pistons are removed and solid skirt aluminum is used to stand the strain and R. P. M. A special intake manifold built of tubing, extra large size to carry a 1-1/2 inch Down-draft Racing Winfield Carburetor with nite racing flywheel is used. Also the Mallory Racing coil and double breaker distributor.
On the half mile track a 48 ring gear and a ten tooth pinion is about the right gear ratio for this work. One of the most important changes is the new type of racing cam shaft that is used with this equipment, which gives reliable results and will bring home the honors and money.
We might also add that the standard Chevrolet wheels have been giving good results in these races.
The Chevrolet Four can be made very fast by using a three in one drive for the magneto, a pressure oiling system on the crank shaft, special high compression aluminum racing piston, and boring out the cylinder to 3% inches.
As the Chevrolet is an overhead valve in the first place, you are permitted to use any special head you desire. The standard Chevrolet rods can be stretched in a special machine as much as one half inch if desired. The Lynite flywheels must be used with this combination to give the high R. P. M.
Pepping Up the Ford V8 The new Ford V8 has been on the floors but one year, but in that time every conceivable test has been given it. The hardest of these tests is dirt track racing. Owing to the time it takes to build up the R.P.M. it is necessary to run these V8 Fords in second gear throughout the entire race.
The V8 Ford is built more like a racing chassis than any other car. It already has the dropped front axle, and the rear spring is underslung. About all that is necessary to make it a real racing chassis is to add heavier shocks.
We now commence to rebuild this engine for real speed and power. The new V8 Ford already has good ignition (Mallory). All that is required is to put on higher compression heads made from aluminum alloy, a new top plate that carries two 1-1/4″ Downdraft Winfield carburetors with velocity pipes and lighten the flywheel and put in a special low gear ratio, 5-1/2 to one.
V8 Easy to Handle at High Speeds This new ratio will enable one to use high gear in these dirt track races. As for lubrication this engine has a full pressure oiling system which also makes it specially adapted for racing. The standard V8 Ford wheels are used with the 5.25 rear and the 4.50 in front. This makes the car easier to handle at high speeds. The special high speed equipment as shown carries a 7 to 1 compression.
On the four cylinder Plymouth we use a special cam shaft with flat tappets. Also, special 30 degree seat valves and higher compression on the cylinder heads; two Downdraft Winfield carburetors with special intake manifold with balance pipe; Lynite flywheel. These same changes are made on the De Soto as well.
We must remember, however, that even though all this special equipment is placed on the stock cars for racing, they will not give the speed and power unless special fuel dope is used to hold down detonation.
For the first time we are giving a comparative fuel chart taken from actual engine test given by one of the laÂ»gest refineries. For every gallon of gasoline we add the following fuel dope: 1.00 Cubic Centimeter…………Ethyl Fluid.
3.85 Cubic Centimeter…………”Day’s Ink”.
46.3 Cubic Centimeter……….Ethyl Iodine.
56.7 Cubic Centimeter ………………..Aniline.
348.7 Cubic Centimeter……Ethyl Alcohol.
572.2 Cubic Centimeter………………Xylene.
645.9 Cubic Centimeter..Benzine (Benzol).
There are about seventeen drops in one cubic centimeter and we add this fuel dope to the regular gasoline and not high test as the high test will burn up the valves.
Modified stock car racing is getting to be universal in all parts of the world. Right now they are getting ready for the Grand Prix Race in Stockholm, Sweden.