Clear-Cut: Setting Ignition Timing | Ground Up Motors

Ignition Timing: Adjusting It Yourself

If you’re staying true to old school with a Small-Block or Big-Block engine under the hood, setting and maintaining the correct ignition timing is crucial. Without the proper timing, your engine will run poorly, can overheat, and get bad mileage. Setting the timing is a simple process and something you should check every so often to make sure it’s still correct.

Tools Needed To Set Your Ignition Timing

You’ll need a basic set of wrenches to loosen and tighten the hold-down clamp. The only special tool you’ll need is a timing light, which can be had for about $30 at Harbor Freight if you don’t already have one. Some option items are a vacuum gauge and possibly timing tape.

Setting The Timing

Prepare the Engine:
- Ensure the engine is at operating temperature.
- Disconnect the vacuum advance hose from the distributor and plug it.
- Make sure all accessories such as air conditioning are turned off.
Locate Timing Marks:
- Find the timing marks on your engine. There are typically timing marks on the harmonic balancer and a timing scale on the timing chain cover.
Initial Timing Setting:
- The timing requirements are going to change depending on your cylinder heads, camshaft, compression ratio, and the curve in the distributor. But a good base would be the 12 to 18 degrees before the top dead center (BTDC). The total timing with advance should be about 34 to 36 degrees.
Connect Timing Light:
- Connect the timing light to the battery following the manufacturer’s instructions.
Connect Timing Light to No. 1 Spark Plug:
- Connect the timing light pickup to the No. 1 spark plug wire. The No. 1 cylinder on a SBC and BBC is the cylinder on the driver’s side closest to the front of the engine.
Start the Engine:
- Start the engine and let it idle.
Aim the Timing Light:
- Aim the timing light at the timing marks on the harmonic balancer.
Read the Timing Marks:
- While the engine is running, the timing light will flash, and you’ll see the timing marks on the harmonic balancer. The mark should align with the specified initial timing setting.
Adjust the Timing:
- If the timing is not aligned with the specified setting, loosen the distributor hold-down bolt.
- Rotate the distributor until the correct timing is achieved. Turning the distributor counterclockwise will advance the timing, and turning it clockwise will retard the timing.
Tighten the Distributor Bolt:

Once the correct timing is set, tighten the distributor hold-down bolt.

Final Steps

Before you take off for a cruise, double-check the timing. Sometimes tightening down the distributor hold-down clamp can you can accidentally twist the distributor. After that reconnect the vacuum advance hose.

If you want, you can check and set the total timing. Rev the engine to around 3,000 RPM and check the timing. The total timing (initial + mechanical advance) should be within specifications.

After you’re done, go drive the car and see how it does. Sometimes you might need to advance or retard the timing of a degree or two in order to get it just right. If you have any other questions or need parts for your ignition system, hop on SS396.com or give our friendly techs a call at (203) 235-1200!