322 - Setting Timing and Carb Adjustment

[1956century]

Hi all,

I'm trying to set the timing on my '56 322 nailhead. I have a timing light but no tachometer. I know the timing must be set before before any carburetor adjustments are made.

The thing that's confusing me is that the throttle stop screw (idle screw? the one behind the throttle linkage) changes the timing just as much as moving the distrubutor does. How do I know what position to set this screw in before I start messing with the distributor? Also, once the timing is set and I play with the screw, won't the timing change?

I've been trying for about an hour but I still get a miss under accelleration.

Could someone outline the correct procedure for me?

Thanks

[JohnD1956]

The 1956 Manual says to reduce the engine RPM to 350 in order to disable the vacuum and centrifugal timing advance mechanisms. Then the timing should be set to 5 degrees BTC.

Note, if you still have the spark plug covers on a crossfire can be induced by running the wires too close together. Since it gets hot under the cover, wires seem to break down easily, especially where they may rest upon the cover's attaching studs. I'd pull the covers off and pull the wires away from the cover studs, then see if that eliminates your miss. If so wrap the wires in the small size plastic wire loam for their length under the covers. This will prevent cross fire.

[1956century]

Thanks for your reply John. My spark plug covers are off.

Since I don't have a tachometer, I have no way of telling where the RPMs are at. Could I perhaps disconnect the vacuum advance line going to the distributor and go from there? Would that mean no matter what RPM the engine is at, the timing shouldn't budge?

[Guest kaycee]

No,

You still have centrifugal advance even with your vacuum advance off and the vacuum blocked off. 350 rpm is just barely idling when the engine is warmed up, so you will be pretty close at lowest idle without stalling.

kaycee

[1956century]

Thanks kaycee. When the engine is at 350 RPM, the timing should be set at 5 degrees, correct?

What I mean is, when I set the RPM and start moving the distributor, the RPMs will increase/decrease. Let's say I set the timing and the RPMs increased, do I bring it back down?

[NTX5467]

BEFORE you set the timing, you should FIRST check the dwell on the points. Dwell time variations have a direct affect upon ultimate ignition timing!

Check and adjust ignition points dwell (there used to be an allen head screw adjustment behind the "trap door" on the lower side of the distributor cap of many Delco distributors. there a "shade tree" method of adjustment, but it would be best to invest in a "dwell tach" to do these things with, in the long run)

Check and adjust timing at the specified rpm

Adjust carb idle mixture for either highest manifold vacuum/highest rpm for the idle speed screw setting. Readjust (tweak) as necessary to achieve the best balance of mixture and idle speed smooooothness at the designated speed.

Sometimes, having the air cleaner installed can affect idle speed, so you might need to compensate for that, too.

If you live in an area with ethanol in the fuel, it can make the carb adjustments not work exactly as they used to, by observation, with all due respect.

When finished, the vehicle should start easily, "die upon command" with no "dieselling", idle smoothly in gear, auto trans gear engagement should be firm but smooth (possibly a little firmer in "R", due to various internal trans design features), and have good off-idle throttle response from a stop. Just as they did when new.

Enjoy!

NTX5467

[1956century]

Thanks guys. I unscrewed the throttle stop screw until it stopped making a difference in the idle and set the timing. After it was set to 5 degrees, I tried to unscrew it more, but it didn't make a difference in the RPM or timing. I think I got it set right.

At idle, there's a high pitched sound (kind of like a spoon hitting the side of a glass) coming from the distributor area. If I push on the distributor, it goes away. If the RPMs increase, it goes away. It's always been there. Any ideas?

Thanks

Edited May 22, 2011 by 1956century (see edit history)

[Guest kaycee]

Hi Alex,

Hopefully the info I gave you last night worked or gave you more info. to work with. The external adjustment type points were'nt used until '57 incidentally, so the points can't be adjusted through a window in the cap on a '56 or older. Try the info that I gave you and phone me back. Good luck!

kaycee