Getting ready to start my rebuilt 223 for the first time. How do I set initial timing? Everything I read says DON'T idle for 20 minutes. The book says set timing at 3-4 degrees BTDC at idle with the vacuum line disconnected, then check advance at higher RPMs and adjust from there. You can't do both!
Thank you
Bob

 

Hi Bob,

The 20 minute run is intended to "break in" the new camshaft. I'm not sure about the 223 but in most other engines you are supposed to do it.

For an initial start up you can "Static" time the engine. Turn the crank over with a breaker bar and socket so that you can feel compression on the #1 cylinder, then using a dowel or something similar, bring the #1 piston to TDC. Your timing mark should be at TDC as well.

Check that your rotor on your distributor is directly under the #1 spark plug wire. Confirm one last time that the firing order is correct and you have the wires on the distributor in the correct rotation. Then take your distributor and rotate it clockwise about 1/2 inch (the advance vacuum module).

Check that your idle mixture screws on your carb are backed out about 2 turns.

Leave the distributor clamp just loose enough to turn the distributor by hand. Have a helper push down on the gas pedal just once and pull the choke cable out about half way and release the gas pedal.

Turn on the ignition and crank the engine. If it doesn't start right up have the helper push the gas pedal just a dash to crack the throttle while continuing to crank.

As she does, slowly turn the distributor clockwise, and the truck should fire up. If not then try backing it off and turning the distributor counter clockwise. Remember it may take some time to get gas up to the carb. It helps if you have it up there already.

Do you have a vacuum gauge? If you do then time it and set the idle mixture with that.

How do you do this? Hook up the vacuum gauge to a port under the carb and disconnect the vacuum advance hose from the distributor and plug it. Start the motor. Turn the distributor slightly to increase the vacuum reading on the gauge at about 700 rpm (or your spec idle RPM). Continuously adjust the RPM to stay at 700 as you adjust the timing. When the vacuum gauge is at it's highest vacuum at 700 rpm, retard the timing just enough to drop the vacuum ONE INCH, and set the distributor clamp in place.

Then adjust the idle mixture screw in such that the motor almost stalls, then back it out very slowly until the maximum vacuum reading is achieved. Go another 1/2 turn in that direction to ensure the vacuum drops then back to the maximum vacuum setting with the screw. All the time maintaining 700 rpm with the idle set screw.

After the mixture is set, go back and recheck/fine tune the timing. When you are done, reconnect the vacuum advance and go drive - no need to do anything else, the engine is timed/tuned perfectly. If the engine pings on your drive, retard the timing 2 degrees and re test drive. Once you have it set, paint a fine line on your balance at the timing mark with white paint. From now on you can check the timing with a light at that mark.

Check that your plugs are properly gapped and your points properly gapped before doing the vacuum guage settings.

 

No Start. I am bummed. Got a couple back fires out of the carb. Thats it.
Rechecked:
All my wiring - OK
Valve / piston timing vs distributor rotor position - it is OK. I tried slowly rotating the distributor while cranking. No Difference.
Checked point gap again - OK
Added a ground from the distributor to the block.
Found & tightened a loose vacuum plug on the intake manifold.
The carb is rebuilt. I can see the accelerator pump adding gas when opening the gas.
Battery spins it over fast.
All electrical components are new, distributor (rebuilt), coil, solenoid, plugs, wires.
Things I am wondering about:
Spark is seemingly weak when I inset a screw driver in a plug wire and watch it jump to the plug. What might cause this? A bad coil? A bad condener? The plug wires are the new modern type,good quality. maybe I need old solid conductor type?
Maybe the carb is off? The glass bowl is showing about 3/4 full. The book talks about using a dummy bowl & tools to set the fuel/ float level. Doesn't say approx how full the bowel needs to be. I set it according to directions during the rebuild.
I am bummed.

 

Normally when you backfire out of the carb, it means that the plug fired with the intake valve open.

Three things will cause this:

First, your timing is grossly advanced (like 25 degrees before top dead center - that happens when you turn it too much and are intruding on the next cylinders firing sequence)

Second, your valve timing is off (timing gears were not alighned properly when the chain was installed)

or most common....

Firing order, or the wires are put on the distributor in the wrong rotational direction, or you are getting spark jump from one wire to another.

I'd try checking the firing order and direction of rotation on the plug wire instal - ONE MORE TIME, making sure none of the plug wires are touching (with my MSD module that spark will jump almost 3/4 of an inch)

Make sure you are starting with the distributor close to Zero Advance and try rotating in BOTH directions if it doesn't fire up (it shouldn't take but and inch or so of movement of the vacuum advance module in either direction to get a start) - advancing first - only an inch or so - then try pulling it back in the other direction.

If that doesn't work then we probably need to look at coil or condenser.

Do me a favor and confirm for me your distributor rotor direction of travel is Counter Clockwise????!!!!????? Thanks!