For most Chevy 350 small block V8 engines, the correct ignition timing typically falls between 2 and 12 degrees “Before Top Dead Center (BTDC)”. However, for good performance, the initial timing of 12 degrees is often recommended. Additionally, total timing advance (incl. mechanical and vacuum advance) should stay within 36-37 degrees to prevent detonation or engine damage.
Getting the timing correct for your Chevy 350 engine isn’t just essential for performance, as it also impacts your car’s fuel efficiency and engine longevity. Otherwise, if your engine’s timing is off, your engine might experience problems such as:
- Hard starting – This is when your car’s engine cranks but struggles to fire up.
- Loss of power – Hesitation, sluggish acceleration, as well as weak throttle response.
- Pinging or knocking – A metallic rattling noise under load could be heard.
- Poor fuel economy – Excessive fuel consumption due to inefficient combustion.
Now that you know the correct timing range and the many symptoms of incorrect timing on your Chevy 350 small block V8 engine, let’s go through the step-by-step process to adjust your Chevy 350’s distributor timing accurately and tune it to the correct timing:
What Is The Correct Timing For A Chevy 350?
First off, you’ll need to determine the compatibility of the cylinder with the spark plug beforehand. To do this, you need to set up a timing light. After that, find the distributor cap and remove the bolts to reveal it. To change the upward angle, turn it in a clockwise direction. After that, to keep the spark plug in place, properly tighten the mounting bolts.
Then, you could check to see if this worked by turning the ignition. Next, you can determine the Chevy 350’s timing marks. When determining the Chevy 350 timing marks, you must, however, exercise caution for a few things. These consist of observing yellow lines while turning and adjusting the mounting using a socket wrench.
Your Chevy 350 small block V8’s timing may change depending on a variety of factors. There is a range by which you can determine whether it is accurate or not, though. The proper Chevy 350 timing marks can be anywhere between 2 and 12 degrees “Before Top Dead Center (BTDC)”. However, spark plugs and plug spacing are the determining elements.
It would also require fewer spark plugs if they were a little thicker. However, the initial advanced, proper time is often 12 degrees. Additionally, there is a limit to this time, which ranges between 36 and 37 degrees. Anything above this range is timing that’s too far in advance. Else, it may suffer from too much vacuum advance, i.e., outside of the range.
Why Correct Ignition Timing Matters On A Chevy 350
Thus far, we’ve discussed the correct timing for your Chevy 350 and how to adjust and tune it to the correct timing. However, why does the correct ignition timing matter that much, anyway? Well, ignition timing determines when your spark plug fires in relation to your piston’s position inside the cylinder.
If the timing is correct, combustion happens efficiently, producing maximum power and fuel economy. However, if the timing is too far advanced or retarded, it can lead to performance issues and even engine damage. So, let’s quickly break down the consequences of poor ignition timing, just so we know how important correct timing is:
What Happens If Timing Is Too Advanced?
When your engine’s ignition timing is too far advanced (e.g., the spark fires too early before the piston reaches “Top Dead Center”), the following issues can occur:
- Engine knocking (detonation) – This is when the air-fuel mixture ignites too early, causing uncontrolled combustion that produces a knocking or pinging noise. When this happens, it can lead to very serious and expensive piston and valve damage over time.
- Hard starting – Additionally, your car’s engine may crank but struggle to start because combustion is fighting against the piston’s upward movement.
- Overheating – Advancing timing too much can otherwise cause excessive heat buildup in the combustion chamber. This could potentially lead to overheating.
- Potential engine damage – If detonation continues to persist, it could cause damage to your engine’s pistons, cylinder walls, and head gaskets.
What Happens If Timing Is Too Retarded?
When your engine’s ignition timing is too retarded (e.g., the spark fires too late, after the piston has already started moving downward), these issues may arise:
- Loss of power – Your engine’s combustion process isn’t completed in time to push the piston down effectively, leading to weak acceleration.
- Poor fuel economy – A retarded spark means inefficient combustion, which wastes fuel and lowers your car’s mileage rating.
- Rough idle and misfires – Late ignition timing could also cause incomplete combustion, leading to a rough-running engine, misfires, or even hesitation.
- Excessive exhaust heat – The fuel mixture in your engine may still be burning as it exits the cylinder, increasing exhaust gas temperatures and potentially damaging your car’s catalytic converter.
Now that you understand the importance of correct ignition timing for your Chevy 350 engine, let’s take a closer look at what the correct timing settings are, and how you could adjust and tune it if the timing is off:
How To Adjust The Distributor Timing On A Chevy 350?
As we’ve explained thus far, distributor timing is essential on a Chevy 350 (and any other engine, really). Therefore, if the timing is off, you’ll need to make the necessary timing adjustments to ensure smooth and reliable performance. With that in mind, here’s how to adjust for total advance timing on a SBC (small block) Chevy 350:
Step 1: Set Up Your Timing Light
Before opening the SBC distributor rotation, you must first grab a timing light (ideally an inductive clamp). The timing light is a special tool for identifying the hues of spark plug wires. Fixing the timing will make matching the right cylinder’s spark plugs easier. Positive and negative clamps allow for simultaneous attachment of two different objects.
For instance, it can link the terminals of a car battery or the coils of a spark plug wire. A digital oscilloscope is another sort of timing light. It doesn’t, though, have any associated clamps. To make the latter option fully functional, you must purchase a pair of jumper cables, as well. Once you have a timing light, move on to the next step…
Step 2: Remove The Distributor Cap And Correct The Angle
Next, you must locate the distributor cap. It’s easy to identify. The distributor cap is easily visible close to or behind the engine. But, you must turn off the engine first before locating the distributor cap. Otherwise, you can’t open the distributor rotation while it’s hot outside. Next, use an Allen key or socket to remove the bolts mounting the distributor cap.
However, keep in mind that removing the bolts completely will cause issues with Chevy 350 timing. The plug wires must then be pointed forward by rotating them clockwise. Then, rotate them counterclockwise, stopping when you see the white turn yellow (this is vital!). When viewed from the front, the distributor rotor should align at the 11 o’clock position.
Step 3: Affix The Timing Light To The Engine
The distributor must then be grabbed, turned clockwise, and stopped when it is precisely in line with your eyes. Alternatively, you may say, “Turn it to 12.” Afterward, secure the plug wires by tightening the mounting nuts with the wrench. You will need some flexibility in the future, so this ought to assist you in making any modifications.
You won’t need to harm any rubber or plastic components within the distributor. So, it should be safe. Once you have the SBC timing marks, connect a wire coil to either the positive or negative end. Depending on the timing light, this process will vary. Both coils must have a minimum amount of space between them, and they must not touch.
Otherwise, there would be incorrect readings, which would interfere with the engine’s distributor and ignition timing. The Chevy 350 timing light should be attached to each wire since the sensor can read them all at once. This should settle the initial timing adjustments, so it’s time to make further fine-tuning once you check the ignition.
Step 4: Turn The Ignition Key On
You must now step inside your car and turn the ignition key on. But keep in mind not to begin in the same position. The timing light dials should be set to 12 o’clock whenever you see that the plug wires are yellow. This normally occurs at 11 o’clock. The crankshaft would be rotating in the interim. Now, the next step is vital, so pay close attention.
Do not start the engine right away to avoid making a mistake! This indicates that the timing light’s timing plug color has changed to white. If it is brown or black, you must immediately replace the spark plugs. Once that’s done, the next step takes us back to the distributor. Just make sure you don’t apply excessive force on the distributor to avoid damage.
Step 5: Put The Distributor Cap Back On
Finally, you must tighten the distributor cap. To tighten the mounting bolts, get the wrench. To see if the distributor cap is shifting, inspect it. And wait until then before starting the engine. Now turn the ignition key to start the engine. Check to see if the speed has returned to normal. Recheck your timing to see if there is anything off. And… That should be it!
It’s a good idea to seek professional advice if multiple attempts to correct the time prove unsuccessful. Again, as mentioned earlier, make sure you never try to replace the distributor by force. Some folks fix it by smashing it against the engine with a hammer and other hard objects. That is the riskiest thing a person can undertake, and doing this will damage the distributor.
In addition, most people also neglect to connect the wires properly when a Chevy 350 distributor is installed. This is another common mistake. Another crucial factor for the distributor’s good operation and ability to serve the engine is the wire connection. Therefore, take care when connecting the wires, and make sure they’re all plugged in and connected properly.
Troubleshooting Chevy 350 Timing Issues
Even if you follow these step-by-step instructions and tune your Chevy 350 engine to the correct timing, you might still encounter issues. They could be due to worn components, incorrect adjustments, or other external factors. To make things easier for you, here’s our troubleshooting table to identify common timing problems and how to fix them:
| Symptom | Possible Cause | Solution |
|---|---|---|
| Engine knocking (pinging) at high RPMs | Timing too advanced | Reduce the total timing to 36-37 degrees BTDC, and check the vacuum advance |
| Hard starting (slow cranking or kickback) | Timing is too advanced at idle | Retard timing slightly, and aim for 12 degrees BTDC initial timing |
| Loss of power or sluggish acceleration | Timing too retarded | Advance timing a few degrees and test the performance |
| Engine runs hot or overheats | Excessive timing advance | Reduce timing, and ensure that your cooling system is functioning properly |
| Rough idle or stalling | Timing too retarded, and/or vacuum leaks | Advance timing slightly, and check for vacuum leaks |
| Poor fuel economy | Timing too retarded | Increase timing slightly for optimal combustion efficiency |
| Backfiring through the intake or exhaust | Ignition timing too far off, and/or incorrect firing order | Check and reset ignition timing, and then verify the firing order (1-8-4-3-6-5-7-2) |
| Engine misfires or hesitates | Timing off, and/or worn distributor components | Check and replace distributor cap, rotor, plugs, and wires as needed |