setting the timing question? 66 VETTE

[Harry L.]

This is on my 66 427 vette. I am just learning, but I have been doing research, so I know the basic fundamentals. My question is, with the engine running,. I pull the vacumn hose off the distributor and plug that hose, that goes to the carb. My car just stops running. Is that normal? At that point should I turn the idle screw way up to keep the engine from stalling? Maybe there is someone who could answer some of my questions? When I am doing this procedure should the air filter be on? thanks for any help! DUTCH

[Jack P.]

Re: setting the timing question? 66 VETTE

This is on my 66 427 vette. I am just learning, but I have been doing research, so I know the basic fundamentals. My question is, with the engine running,. I pull the vacumn hose off the distributor and plug that hose, that goes to the carb. My car just stops running. Is that normal? At that point should I turn the idle screw way up to keep the engine from stalling? Maybe there is someone who could answer some of my questions? When I am doing this procedure should the air filter be on? thanks for any help! DUTCH

There are many articles by John Hinckley on this very topic. He is a member. Yes to start turn up idle to a point that car runs. You can then check your timing. It may be about 4 to 8 *s, You have to check you spec table. Look for his two part thread on the topic. It is not difficult once you know what to do. You need a timing light to look at mark on balancer and tab on engine timing cover.

Jack

[Mark F.]

Re: setting the timing question? 66 VETTE

What's happening is that the vaccuum advance can (vac) is engaging the advance at the idle rpm that you have it set at. When you plug it up it stops the advance and the car stalls. Providing that everything is function correctly. ie vac, carb etc. First thing I would do is yes bring the rpms to aprox. 600rpms with the vac disconnected. Set my intial timing at 10-12 degress btdc ( on the crank) You will have to go over your idle mixture screws on the carb. To Highest vaccuum/ idle. Reattach vac adjust curb idle.

[Duke W.]

Re: setting the timing question? 66 VETTE

Just set the idle speed as low as possible that will keep it running with the VAC disconnected and plugged. Increase engine speed to see where the advance starts. If the speed it will keep running is less than this, set the timing at this low speed.

Don't mess with the idle mixture screws until you have set the initial, reconnected the VAC and set the idle speed to the normal setting. Then do the idle mixture/speed adjustment.

You didn't say which '66 427 (please, always specfiy the specific engine), but since it appears to have full time vacuum advance, I assume it's the 390 HP version.

The specs I have for that engine call for an initial timing of 4 deg. nominal with a range of 4-10. Run it as high within this range as possible without detonation.

The centrifugal should start at 900 and the maximum is 30 @ 5000, so you should be able to set the initial at below 900, but I have no idea if the centrifugal curve has been modified. That's why you have to test to find the speed that it starts.

This data should be in your CSM. Don't mess with the car without one.

Duke

[Harry L.]

Re: setting the timing question? 66 VETTE

Do I plug the vacumn hose and also plug the carb at the vacumn port at the same time? Yes it is a 390 hp. Does my factory air conditioning, contribute for making any special adjustments? DUTCH

[Jack P.]

Re: setting the timing question? 66 VETTE

Do I plug the vacumn hose and also plug the carb at the vacumn port at the same time? Yes it is a 390 hp. Does my factory air conditioning, contribute for making any special adjustments? DUTCH

Just take line off Vac can and plug the line with a golf tee, it works great. The VAC can does not need any plug. It is made inactive when you removed the line , which is what you want, to get the timing * base and to set new one if necessary. As to the AC, after setting timing, and plugging everything in, turn on air and then set idle to keep engine running, you can then set idle mixtures also.

Jack

[Harry L.]

Re: setting the timing question? 66 VETTE

Thanks Jack, that is exactly what I wanted to know. DUTCH

[Jim T.]

Re: setting the timing question? 66 VETTE

Harry since this is new to you I suggest one more step. When the engine is not hot remove the distributor cap and remove the rotor.
Remove the centrifical advance springs and the two centrifical advance weights.
Clean the pivot points and where the centrifical advance weights slide.
Your option, extremely small amount lubrication can be used on the sliding area and the pivot points.
Also recommend removing the distributor tack drive gear, clean and lubricate with grease.

[Timothy B.]

Re: setting the timing question? 66 VETTE

Harry, Remember after you set the inital timing and connect the vacuum advance to warm the car very good before adjusting the idle emulsion/mixture screws.

My 67 idles about 100 RPM's higher with a completely warmed cast iron intake manifold, (car running about fifteen minutes). I think this is because the heated cast makes vaporization of the fuel better. On my 67 the emulsion screws can be leaned slightly and they are approx 5/8 turns out.