I made a new discovery last evening. I brought the timing down to 8 BTDC and readjusted the idle to 550-570. All of this with the carb plugged at the vacuum advance port. A test drive resulted in pretty sluggish low speed the hesitation from any stop was very evident, and the surging continued at cruise speed.



I then decided to open the distributor for the first time since I purchased the car. I found it has an PerTronix Ignitor conversion installed. Would having this require any changes in my investigation tests to find out why this car isn't running well?



SIDEBAR:



Turning the distributor counter-clockwise to bring the initial timing down to 8 degrees had a scary side effect. During the test drive, when I pressed hard on the throttle, the throttle suck partially open, causing a immediate stain in my shorts. I had to quickly get my foot under the gas pedal and lift it up. Once back in the garage, further inspection found that the tach drive cable got tangled in the throttle linkage holding partially open. This was not an issue when the distributor was turned much further clockwise. I modified the routing of the tach cable to prevent this from happening again.

pops (AKA) Clay

'56 Thunderbird

Pops:

You said there is awhite paint mark at what you assume is TDC.  Better verify that, someone may have put the dot at 42  degrees and used it to check total advance.  If it's at about 40 and you add 10 to that for the initial setting, you'll have 50 degrees at idle.  Way too much.

John - "The Hoosier Hurricane"

If you are running a pertronix, make sure the red wire is getting 12v and not reduced voltage from the ballast resistor. The pertronix needs 9-12v to function properly.

Okay guys, I will get #1 to TDC on the compression stroke to confirm the position of the white mark, and will also confirm the red wire is getting 9-12VDC and report back.



Thanks for sticking with me on this.

pops (AKA) Clay

'56 Thunderbird

I can confirm the red wire going to the dissy is getting 12V (on the incoming side of the ballast resistor) and the coil is getting just over 6V via the ballast resistor.



And I THINK I can now confirm the white mark is TDC. Took #1 plug out, brought the white mark to the indexing point, felt air pushing out of spark plug hole, took off the dissy cap and the rotor is pointing to #1 cylinder. Also, there are 4-5 graduated marks above the white mark each about am eighth inch apart. So, I think the white mark is TDC.



While I had the plug out I took a pic of it.

pops (AKA) Clay

'56 Thunderbird

Pops

Can we start over please. Tell us what car, what transmission, what year? The car ran well for 500 miles with only a couple of minor items and the it suddenly did not run well ? Is this correct?

And now you are convinced that the problem is the timing, right? May I suggest that you first find the Ford factory mark on your pulley and that you put a paint mark on this so you can see it.

Try to determine if your Pertronix is Ignitor or Ignitor II (they are different) Ignitor will use a ballast and runs on reduced voltage not full 12 volts.

Try to keep an open mind about the cause of your problem it might be a lot of different things so do one thing at a time. Start with the engine timing and when that is set then find out what else is going on with your car. Pete

I have an open mind because I'm a little lost. I'm not convinced it is the timing, but noting that it appeared to have 55 degrees of advance in it at idle left me scratching my head. And the more I retard it, it seems to be more and more sluggish.



I'm open to try anything that I have the test equipment and the ability to attempt.



Here is what I can tell all about the car. I bought it in October 2010 and have driven it about 500 miles since.



'56 Thunderbird with a '57 312 engine and Ford 'O Matic trans

Holley 4bbl list 80457-5 Date Code 1786 (appears to be an after market 600 cfm carb from the list number)

'57 dissy with tach drive

PerTronix Ignitor -"Ignitor" is written on the module (does NOT say "Ignitor II")

Autolite 46 plugs



I feel I have identified #1 at TDC by the white mark on the lower pulley. There are 4-5 graduations in the pulley above the white mark. There are NO graduations below the white mark. The white mark was at the pointer with the rotor pointing to #1 cylinder on the dissy.



The car has had a stumble/hesitation starting off from a stop early on.

Stabbing the throttle gets me beyond the hesitation



The car surges when at a steady cruise speed of 55-65mph

Letting off or pressing the throttle further clears the surging until you stay at a steady cruise speed for a little while again. Then the surges re-emerges.



My test equipment consists of a timing light that also measures RPMs. The light has buttons to advance or retard the light

I have a cheapo dwell meter, and I have a vacuum gauge.

pops (AKA) Clay

'56 Thunderbird

To help with diagonisis, get vacuum reading at idle and that may give ballpark indication of part of problem.

  AussieBill            YYYY    Forever Y Block     YYYY

 Down Under, Australia

Specs for output sise of resistor are 5.5-6.5 max so you are OK there.A thought regarding distributor breaker plate ground.There is a copper braide wire inside distributor which goes from breaker plate on top to under it and grounds it to distributor.Have  a real good look and make sure it has not broken under the plate causing intermittent loss of ground when the distributor plate turns as  timing advances.That has been seen on more than a couple of occasions causing loss of power.

  

Clay

Take AussieBill`s advice and hook a vacuum gage to your intake manifold and post the reading you get at idle.

It seems impossible that your car had 55 degrees of initial advance and still started ( my experience is that it won`t turn over with that much advance)

Your timing lite might be giving you wrong info, make another mark about 1 inch from your white paint mark on the pulley  AGAINST the direction of rotation of the pulley and check with the strobe lite and your number one sparkplug wire as the engine is revved up and see if the timing is advancing as speed increases. Then set the timing with the strobe lite and WHITE paint mark not the dial-back feature of your timing lite.

Another possibility is your coil is failing but only consider that AFTER these simple easy things are done. Pete