Chevy Small Block timing

Here is an older blog when I got a question about timing a Chevy small block. I also slapped some timing videos on the end of this post, on "how to set your timing videos" I made on youtube.

-B-

Ironically this question was asked at the same time I am getting ready to time my 327.

All Chevy’s are pretty much the same timing wise.
Check your coil and electrical to be sure and catch any future problems. Give the fuses a once over. Rotor should turn with crank. Should have twelve volts on the live from the coil when the key is on, and during crank. Negative coil wire should flash with crank (when on a tester), if it is on or off all the time module is bad. Check for spark at plug boot. Ok all that is good time to set cold timing. (I unhook the advance and plug it if not for anything other than to get the hose out of my way)

Take out your number 1 plug, firing order is 18436572, clockwise. Put your thumb over the plug hole and bump over, or manually crank the engine until air pushed out against your finger. That is the compression stroke. Crank until your timing tab is lined up with the timing mark, at 0. (if you have one the block if not you should mark the tdc once it is set) Either way if you have a timing tab or not, insert a soft wire, or dowel into the plug hole so it rests on the piston. As the piston comes up when you crank it the rod will push out, when it hits top that is top dead center for your number 1 cylinder. After tdc the pistion will start to drop again.

Even if you have a tab double check with the dowel or wire that 1 is really truly on Top Dead Center.

Hopefully it matched the tab, makes futures timing much easier, if not mark it.

Take the cap off the dizzy. See where the rotor is pointing. The metal piece that sticks up and touches the towers on the cap should pointing to the number 1 cyl tower on the cap. Now mark this on the dizzy, place the cap back on so a tower is lined up with the rotor. (Mark this! so 1 is right under 1, mark the cap, and dizzy) This is your new number 1 tower. Take a wire and put it on this tower run to your 1 plug.

Plugs are; driver’s side from front of the car 1-3-5-7. passenger from front to back 2-4-6-8, order from plug one on the dizzy is 1-8-4-3-6-5-7-2, so take wire one from tower one to plug one, then go around clockwise, tower 8, wire 8 to plug 8, and so one with tower 4, 3, 5 ect . . .
It doesn’t matter which tower is 1, as long as it goes to the number 1 cyl at TDC. Normally it is one of the front two, usually the one pointing toward the driver side, on newer HEI dizzy’s it was the one pointing toward the passenger side, but when you set this your self it doesn’t matter.
This is on cold timing now. If the carb is dry prime it through the "over flow" or breather tube in on carb, get some gas in the fuel bowl. Give it a turn, and see what you get.

The motor should run, maybe not the best, because the advance is still not set. Just sitting it
should be fine.

The next timing adjustment is the biggest pain. (You don’t need a timing light but it helps) For most small blocks to have peak performance you need to adjust the timing to fire before top dead center. This setting depends on the engine, but a good rule of thumb is it will fall into 6-10 degrees before TDC.

The easy way to do this (if you have a good ear this will be a breeze) is to loosen the cap and turn it, or warm the car/truck up, shut it off, loosen the distributor clap bolt, holding it in place, start the car. Now the rotor turns clockwise, so slightly, very slightly, turn the dizzy counter clockwise (the way you would turn a nut to loosen it) just turn it a hair. a full circle is 360, half is 180, a quarter is 45, so 6-10 is just a slight turn. Use your mark on the cap and dizzy as a reference.
Ok turn it until the engine sounds good. If you don’t have an ear for this, then you need a timing light. Take the light hook it up and follow the directions. The light is used to tell you when 1 is sparking by flashing. The flash should be shining on the timing tab to you can read the ’s on it. you adjust the dizzy until if flashes when your timing tab is 6-10, instead of 0.

Also hook up a tach so you can get the RPMs. Each engines are different, but a idle in park of 600-800 on a warm engine is usually decent, depending on the motor/performance parts. Again a good ear will help this. Adjust the timing and carb to get the rpm’s correct for your engine. The carb is a whole other beast, and there are too many to give a good guide here. But there is a fast idle screw, this should be #1 suspect if it ran fine before and timing is on. Get or find a guide to your carb and adjust accordingly if needed.

After this is set, it is all just tuning, which never ends.

Don’t forget to hook your vacuum advance back up. This won’t really affect idle, it kicks when you cruise to save you gas. So the vac advance is set later, you need to drive it and watch for flat spots or pinging then adjust the vac canister.







http://www.youtube.com/watch?v=BBywvhXLFZE

http://www.youtube.com/watch?v=yxyjA6v2G6Q

http://www.youtube.com/watch?v=9yqYDP7D_8M