How to Check Dwell Angle in a Car

How to Check Dwell Angle in a Car

Dwell angle can be defined as the period measured in degrees of rotation of the cam distributor when the contact breaker points are closed in order to spark the primary windings of the coil. An inaccurate dwell angle will affect the ignition timing causing your car to not startup. Checking and fixing a dwell angle is very easy; all you need is the right testing tool. Read on to find out how to check dwell angle in your car and make any necessary adjustments to rev up your car’s ignition.

Issues with the Car’s Ignition

The spark timings are greatly affected if the dwell angle is not set at the recommended angle. If the angle is smaller or larger than the recommended angle, the spark timing can differ greatly. It can either become too advanced to damage the coil or too retarded to start the car. You should also change spark plugs in your car regularly for better results.

Besides improving the spark timing by adjusting the dwell angle, you can also bypass a kill switch to save time.

The dwell angle for all the cylinders has to be uniform; otherwise, the car does not run smoothly, and the fuel is also not utilized economically. You should also regularly clean the pistons to improve the engine’s efficiency.

It is best to look out for other reasons why your car doesn’t start as well and along with the signs for an oil change so that your car can function properly.

Your car’s ignition works with a key, but you can also start the car without a key. Most modern cars have electronic ignitions now and don’t require dwell angle adjusting. However, they require a master key to start. In case you lose the master key, you can easily program another key without the master key.

Tools for Checking Dwell Angle

There are certain tools by which you can check dwell angle in a car; some of them are listed below.

  • Feeler Gauge – The most basic way you can check your car’s dwell angle is by placing a feeler gauge, a thin metal strip used to measure the gap width between the two contact breaker points. It gives you a rough idea but not an accurate measurement of the dwell angle.
  • Dwell Meter – A dwell meter is the most preferred and is a specifically designed tool to measure a car’s dwell angle accurately. It is a simple device with two crocodile clips.

You have to clip the negative lead with the car’s earth and the positive lead with the side terminal of the car’s distributor or the contact breaker terminal on the coil while the engine is still running. A dwell meter would give an accurate reading of the dwell angle.

  • Multimeter – Multimeter, as the name suggests, is a multipurpose device that can help you measure many different electrical components and aspects of your car. Not all multimeters have the option to check the dwell angle. Ensure that the multimeter that you wish to use on your car has a dwell angle measuring feature available.

Set the meter to dwell scale and press the ‘cly’ button on the meter to update the number of cylinders your car’s engine has. Now place the meter’s black lead on the car’s ground and the red lead to the coil’s negative terminal.

Note: You can also check other electrics using the multimeter. It is best to test your car’s battery and check the battery’s leads and connections as well, in order to ensure that sufficient power is being supplied to all the electrical components.

Checking and Adjusting the Dwell Angle

Dwell angles vary depending on the engine cylinders in your car. It is best to consult your car’s owner manual to find out the exact dwell angle recommended for your car. If your testing tool gives an incorrect dwell angle, you can easily adjust its dwell angle to the required angle. Follow the following steps to check and adjust a dwell angle.

How to Check Dwell Angle

Step 1 – Firstly, you have to turn your car’s engine on and let it run till it reaches its normal working temperature.

Step 2 – Now connect the dwell meter or the multimeter to either the distributor or the coil from red lead and connect the black lead to the car’s ground.

Step 3 – You will now notice a dwell angle reading on the screen of the dwell meter or the multimeter.

Step 4 – Now, compare the dwell angle reading shown on the meter with the recommended angle for your car as mentioned in your car’s owner manual.

Step 5 – If the angle on the meter does not correspond with the angle mentioned in the manual, you need to adjust it.

How to Adjust Dwell Angle

Step 1 – You have to turn the engine off first.

Step 2 – Now, you need to locate and remove the distributor cap and rotor arm from the car’s distributor.

Step 3 – You have to find the contact breaker points on the distributor shaft and increase or decrease the point gap between the two contact breakers in order to reach the required dwell angle.

Step 4 – Now, you need to put the rotor arm and distributor cap back in place.

Step 5 – You should turn the engine back on and reconnect the dwell meter or multimeter to the distributor and ground again.

Step 6 – Check if the reading is accurate; otherwise, you need to redo the adjustment steps from 1 to 3.

Safety Warning

You should never run your car’s engine in an unventilated area. If you are working in a garage, make sure you have the windows and the garage door open so that there is a constant flow of air. Working in closed spaces with the engine on can cause carbon monoxide to build-up, which can cause carbon monoxide poisoning and eventually lead to death.

Knowing how to check the dwell angle can help you maintain your car’s ignition system. Easy adjustments of the contact breaker points by yourself can eliminate the need to seek professional help at the mechanic for simple tasks such as this, saving you time and money.