Idling & timing confusion

[Sammy]

After reading the manual and many threads here on the forum I'm still confused about 
a correct idle speed.

As I understand it now:
1. Vacuum lines to distributor connected
2. Complete warmed up
3. Shifter in D
4. Idle speed should be at 480 rpm
Correct so far?

5. Now I put the shifter in P - idling speed rises a little of course 
6. With this slightly higher idling I disconnect the distributor vacuum line and measure timing
    or do I need a second person to sit in the car and shift to D while checking timing?

Thanks a lot,

Sammy

[Jason Edge]

The 63 shop manual in Ignition Timing Adjustment Section 23 Step 5 simply states "Set idle speed at 480 rpm."

The 64 shop manual in Ignition Timing Adjustment section clarifies a bit in Section 23 Step 3 where it says "Disconnect parking brake vacuum hose at diaphragm and place a piece of tape over end of hose to prevent any air leak."

and in Section 23 Step 8 where it says "Set idle speed at 480 rpm with transmission in "DRIVE" POSITION".

It seems Cadillac in 1964 realized they were a bit vague in the 1963 shop manual description and added more verbiage.

Just to add to "lock" the car from moving forward in the idle speed adjustment section (and the 1964 timing adjustment section) it indicates you should disconnect park brake, plug hose, put in Drive.  The park brake vacuum is of course disconnected to prevent it from releasing when you put it in a "drive" gear.

There are of course other ways of doing this without disconnecting the park brake such as having a helper hold the brake, or firmly choking the tires (be careful here as the car will run right over small bocks), I have used four 6"x6" blocks to hold it in placed. 

Hope that helps.

[Sammy]

Thanks, think that's it. 
Does your rpm vary when dist vacuum on or off?

[Sammy]

How to set ignition is no problem, done this several times on other cars,
The confusion was only with the preconditions unclear in the manual. 

Checked it yesterday, when idle is set at 480 rpm in "D" mine is running at 610 rpm when in "P".
5° at 480 and 7° at 610. 

[38oqogaboqfax]

i believe if your engine is still in good mechanical condition then running it at a low 480 RPM in Drive is possible, but if you have a stretched timing chain or the engine is very worn, than I don’t think it’s possible to have this engine run smoothly at 480 RPM in Drive especially with crappy watered down fuel we have today out here in CA

I’ve tried for the longest time to get my 64 to run smoothly at 480 RPM’s in D but the engine starts to idle roughly when the timing mark is at 5° BTC. It runs a lot smoother at 7-8° BTC and but then the idle is too high at times and the transmission slams into gear. I feel like the sweet spot is 6-7° BTC for my engine. The weak fuel today also plays a part I believe in why so many of my other classic cars run poorly on the stock setup.