installed a new distributor. The one in it was the original and so worn that timing would jitter and the vacume advance would advance at idle.

New engine starts well enough. I check that adjusting the idle speed does not affect my timing mark as the old one did. I turn the dizzy to 8 BTC. I notice that the idle is much smoother with no misses and I think that I have this last problem solved on my partial rebuild.


Problem:
I begin to remove the vacume advance to check static timing and she dies immediately.
I check total advanceand it is only about 22-24.

Will not start with advance tube removed/plugged to check mechanical advance.

QUESTION
How can I tell if it is mechanical or vacume advance if I cannot remove the tube and keep the car running?

Anyone else have issue with rebuilt distributors? This is the third one that I have tried with no luck. Rotor would not settle down on the first, the second wasflared on the tip and would not fit into the cylinder around the oil pump drive shaft. Now this one will not advance timing.

Frustrating.

 

Post this on the engine section of Hotrodders.com. There are a lot of knowledgable people there who have helped me with more techinical quetions.

Good luck.

 

Sounds to me like you have (and always had) the vacuum advance line hooked up to full manifold vacuum instead of ported vacuum, so you're getting full vacuum advance at idle. When you remove the vacuum advance line, the vacuum advance goes away and leaves the timing probably well after TDC, killing the engine.

Set the timing with the vacuum advance disconnected and plugged. That's your base timing. Then, with the VA still unplugged, rev the engine and check for total advance. Ideally you should see 28-32* all in by about 2800rpm.

Then you can go and figure out which port on the carbyou're supposed to hook the VA line to. Youshould see almost novacuum at idle when hooked up to ported vacuum, and an increase as you open the throttle.

 

That is just what I was thinking. Go with Starfury's reply.

 

Thanks for the reply,

Carb is autolite 2100, vacume tube is metal and original (pre-bent to the port).
There is only one vacume port on the autolite 2100 and it is located on the front passenger side.

I am getting 1-2 pounds of vacume at 750rpm (where I had to set my idle screw with old distributor) and about 10 pounds of vacumeat 1000rpm at the carb port (it is the correctand only port.

It affected the old distributor greatly ( I could adjust my timing anywhere from 8 to 20 using just the idle screw!! ).


Question Is there any way a backfire, leaky seal, anythingetc. would cause me to start getting vacume at thecarbuerator port. (it is the correct port) )

 

1-2 inches (not pounds) of vacuum isn't bad, but I'd try to drop the idle down if possible. You might check for some play in the carburetor throttle plate shaft as well.

Recheck the vacuum too, and reset the timing with the VA disconnected. 1-2" shouldn't be ramping the advance up that much, but you should be able to get by.

 

Before replacing the distributor I was getting about one degree advance per inch of carb vacume.

The one I put in last night corrected all of the problems I had with the first 40 year old one, I have smoother idle without miss and steady timing when adjusting curb idle speed. Now it seems like the vacume advance is the only thing keeping it running.

I will try to crank it with the vacume advance already plugged to check static timing, but am at work and it will be later tonight.

Thanks again,
Brad

 

Advance it a hair, then crank it and check the timing. It won't run if the ignition is that retarded (literally, not figuratively). Then hook up the VA and check again. It should barely, if at all, affect the timing at idle.

 

OK.
Got home from work. attempted to start but no luck. lots of studdering though.

took off the distributor cap and noted that the rotor was rubbing the interior of the cap and that the brass tip of the rotor was actually striking each brass pole of the distributor cap.
I guess this explains why it would not advance. Because the rotor was meeting physical resistance/friction from cap.

Problem is that the rotor only seated 3/4 of way onto the distributor shaft.

Bought a new rotor and it will only seat 1/4 of way onto shaft. (slot on shaft is too narrow for the plastic "key" on the inside of the rotor to slide completely down) The cap would not even clip on.

Guess I'm going to return this distributor or try to shave off of the width of theplastic tab inside the rotor so it will seat completely.

 

First I want to thank all who have taken the time to look into my issues and help me out.

What I have found out
1. with the new distributor (installed to the same place as the old that I took out) I need to rotate all the way to the water neck to get timing at 5 BTC static. I realize that I will need to rotate the shaft counter clockwise a tooth and I'm guessing that the old one had to be installedoff a toothto account for being old.
2. New distributor did make engine run smoother at idle, timing mark issteady.
3. New distributor did not change fact that my idle speed significantly affects idle timing.


LOTS OF DATA :

Idle in park @ 650
5 Degrees static timing (all I could get without shifting a tooth counter-clockwise)
2 inches of vacume at carb port
mechanical advance 22 by 2500
total timing >40 @ 2800

After any revs, idle settles down @800 with 25 BTC timing, when warm.
* If I briefly disconnect vacume advance, idle instantly returns to original 650 and 5 BTC, but willrise to 800 and 25 BTCand is steady there after revs, at idle, unless vacume line is disconnected/reconnected.

Carb port vacume readings,
@650 2 inches of Hg
@700 5 "
@1000 14 "
@2500 17 "


QUESTIONS:

1. Mechanical idle 22 OK?
2. What would make my total advance >40 with static @ 5? Is that OK long as I do not ping?
3. Is it normal for engine to settle down to base timing and idle speed after reving it up a little?
Mine will idle at25 degrees BTC and 800 rpmfollowing any revs. It returns to baseline of 650 and 5 BTC after relieving vacume, by unattaching and re-attaching vacume line from vacume advance port on dizzy.
4. Do my carb vacume readings look OK?
If I idle @ 650 it does not affect my timing, but @ 800 idle timing advances to 25 degrees due to vacume.

PROBLEMS:

Idle speed seems to greatly affect my idle timing (because of the vacume advance). I can set it at 650 and 5 BTC, but it will advance and remain at 800 and 25 BTC after any pedaland return to idle, unless I physically remove and replace the vacume line at the distributor,to relieve "pressure".

Total advance is >> than 40 with static set @ BTC.
Is this really a problem as long as engine runs fine and does not ping?