The 13B motor in the Mazda RX7 is designed to be easy to time. If you notice a rough idling sound, or the motor shakes, start by setting the timing yourself to see if you can solve the problem without having to pay a mechanic. The timing will smooth out and prevent stressing engine mounts or exhausting excess fuel. Do the procedure in order, and you will straighten out the timing in a few minutes.
Locate the leading and trailing marks on the main pulley. Stand on the driver's side to do this. The pulley is marked at the factory with the terms "Leading" and "Trailing." If your motor is old, these labels may have worn off, but you can still identify the marks by looking from the driver's side and seeing how they are grouped. The leading mark will precede the trailing mark by a few inches.
Identify the pin on the front cover. It is on the driver's side. You will need to use this pin to set the timing, so be sure you see it clearly. It is in line with the crank angle sensor, which looks like a distributor cap.
Connect your timing light to the leading coil pack. It is by the battery. You will find two wires. Either wire will work to connect the timing light. Place the timing light on one of the wires so that it will fire.
Shine the timing on the pulley. Check to see if the leading mark is lined up with the pin on the front cover. If it is not, use your hand to turn the crank angle sensor until you see the leading mark line up with the pin on the front cover. It will look like it is slightly off center once you have it adjusted correctly.
Locate the trailing coil pack by the brake master. Place your timing light on the front wire of this coil. You should see this wire fire on as the "trailing" mark passes. You cannot adjust the trailing mark timing. This is simply a double-check to see if your motor is working right. If the trailing mark is visible in your timing light during this check, your timing is correct.
