How do you set the timing on a small block 350 Chevy for a z28?

Answer 1

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, 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 #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 on the block if not you should mark the tdc) 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 #1 cylinder. This should line up with 0 on your timing tab (not always sometimes the timing it set after, or someone take the tab off, it is just a piece of marked metal usually above the "big pulley" below your fan.)

So 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.

Take the cap off the dizzy. See where the rotor is pointing. The metal piece that sticks up and touches the towers should pointing to the #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 #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 #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 the carb to 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 un hooked. Hook it back up and see if this changes your improvement. Just sitting it should be fine.

The next timing adjust ment is the biggest pain for me. (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) take the distributor, loosen the bolt, hold it in place and start the car (warm it up shut it off loosen the bolt) so holding it in place, start the car. Now the rotor turns clockwise, 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. 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.