How To Adjust Ignition Timing

[8695Beaters]

Ignition timing is a great little trick to squeeze some more power out of your car. You can tune it without a dyno or computer, and it only takes a few minutes.

It's pretty simple really. Rotating your distributor will adjust when it fires the spark plugs. If you advance the timing, the spark will ignite the air and fuel a bit earlier and allow more combustion, creating more power. Advance too far though, and the mixture will ignite before the piston reaches the top of the cylinder- then you have knock, which will destroy your engine if you let it go too long.

Advancing timing is really easy. But before you go ahead and wrench, you need to know how far to go. Timing is measured in degrees (relative to the crankshaft). But the distributor isn't marked. Some basic high-school math will tell you how far to go: arc length. Just measure the width of your distributor (millimeters works best). Divide that by two (the width is the diameter. D=2R, remember?). Then multiply that by Pi/180 (0.01745). That's your arc length.

The number you just came up with is how far you need to rotate the distibutor to advance the timing one degree. If my guessing is correct, a typical Honda distributor is about 9 cm wide (since I am not looking at one right now, I'm not sure). Push that through the formula and you get about 0.8 millimeters to advance one degree of timing. So one millimeter will be sufficient as one adjustment.

To physically tune your ignition timing, you will only need one tool: a socket wrench. Find your distributor and look for its mounting bolts. Make sure you aren't looking at the cover bolts. The mounting bolts will be slotted. mark where the distributor is now with a marker or some chalk. Break the bolts and loosen them so the distributor can rotate. Don't take them all the way off, or you will be up a creek. Rotate the distributor 1mm COUNTER-CLOCKWISE to advance the timing. Tighten it down and get in the car with a friend.

Drive through a tunnel or by a solid wall. Then give the car full throttle. Have your friend stick his or her head out the window. They will be listening for pinging (knocking). If you don't hear any pinging, drive back and advance the timing one more millimeter (or if you were smart, you brought your socket with you). Advance it until you hear pinging (the moment you hear knock, stop running your car hard). Then turn it back one setting and you are done.

Some things to remember about this: It will work best if you use premium gas. I wouldn't rey this on regular 87-octane. Remember, your car came from the factory already optimized for that gas. Higher octance gas will raise the knock-threshold and you can turn up the wick with less worry. I haven't tried this on a car with regular gas, so feel free to try that first. However if you do use premium gas, you will have to use only premium gas. Lower octane will cause knock.

If you get an ECU reflash or a chip, make sure you reset your timing back to stock. Most of these types of upgrades tell the ECU to advance ignition timing on its own, and assume you have not touched it. All of a sudden you are pinging. So don't forget that you have already done that to your car.

This also won't work on cars with knock sensors (most OBDII cars). You can use a timing light to help you out, but the car won't knock, it will just take out ignition timing (wonder where they got the idea?).

Also, the counter-clockwise turning is only for Hondas. All of Hondas old engines (basically pre 2000), all turn the opposite of everyone else. The K-series turns the normal way, so you may have to rotate the distributor clockwise. Check the service manual if you have a newer car.

Enjoy your free tuning tip.

DISCLAIMER: The contents of this article are not necessarily the official views of, nor endorsed by, the owner of HondaClub(com).

[Superman]

Thanks a million this is a great read!

[marcos]

what did you mean by
then turn it back one setting and your done?
you mean turn it back 1mm?

[8695Beaters]

Yes. If you go to the point where you reach knock, then logically,turning it back 1mm would bring you back away from knocking. Just watch out for bad gas.

[marcos]

oh okay I get you
so no knocking = good

[8695Beaters]

Yes. Knocking is very bad for Otto engines (typical 4-stroke car engines). Basically the air and fuel start igniting before the piston is ready to go back down. This puts a lot of stress on the pistons, the rings, the connecting rods, and everything in the engine. It sounds like a hammer is hitting the top of your piston, which is exactly what the damage looks like. Too much will eventually destroy an engine. But rotaries (like the RX-7) will be dead after just one ping. So letting knock run at all is really bad.

FYI, I got some real numbers for the distributor and updated everything, so use them instead.

[marcos]

oh okay okay thanks beaters
i'm gonna try this this weekend

[Lawless28]

that is very well writen. thanks for the help

[8695Beaters]

Thanks for the kind words guys. In June I plan to start writing a lot more tech articles. I think this site is sorely lacking in info like this. I think most sites are lacking in good, easy to find tech. It's all just specific posts about specific topics, no how-to's or anything general like this.