Still struggling with car at idle after 8 years

[AK260]

Gundee already mentioned this but one cylinder does not seem to be getting spark.  It's not firing.  That's why it's clean.  I'd fix that before going any farther.  No real value in tuning for five cylinders.
And if one cylinder is completely sparkless it kind of makes you wonder if the others are getting consistent spark.

You’re absolutely on the money there. I’m now imagining a scenario where running on 5 cyls has caused the lack of power and the carbs are being richened up to compensate - hence fouling all other plugs at idle.

@Jalex - Quick way to test it is to completely take off both spark plug leads from 1 and 2 (at both the distributor and spark plug ends) and swap them so that what was no.1 lead is going from 2 on the cap to spark plug 2 and what was plug lead 2 going from 1 on the cap to spark plug 1.

Then go for a drive and pull the plugs. Now if no.1 plug fouls, you know you have a lead or cap/rotor problem (Or possibly the plug itself).

[Mark Maras]

@jalexquijano Modified test plan. Perform the test as described above except don't unplug the plug wire from the cap. Remove the cap with the wires intact and measure the resistance from inside the cap to the positive electrode on the plug. 

[gundee]

On 10/29/2023 at 1:10 PM, jalexquijano said:

Car runs good at 3.5 turns clockwise on both carbs. Timing advanced to 14bdc. Plugs BPR5ES from 6 to 1 

Rear carb is trying to make up for the front carb being too lean. Clear to see.

Still don't know why. Likely an air leak up front.

Also set your timing up to 17 degrees from 14.

[jalexquijano]

On 11/1/2023 at 4:46 PM, Yarb said:

The electrical spark issue is what you need to be concentrating on right now. 

Ok. What should we tackle first? Floats adjustment with float syncs, or swapping spark plug leads or spraying carb cleaner to determine fuel leaks? Too many directions. I can also clean the 6 plugs with a brass brush and enrichen the mixture from 3.5 to 3.75 at the front carb and sent you pics of the 6 plugs. 

Let me know the course of action.

[Yarb]

IMO fix the spark issue first. Way to many variables here.

[Mark Maras]

23 hours ago, Mark Maras said:

@jalexquijano Modified test plan. Perform the test as described above except don't unplug the plug wire from the cap. Remove the cap with the wires intact and measure the resistance from inside the cap to the positive electrode on the plug. 

 And I want to know if you're using anti-seize on the sparkplug threads.

[jalexquijano]

19 minutes ago, Mark Maras said:

 And I want to know if you're using anti-seize on the sparkplug threads.

No. Need to find one at local store. You want me to measure the resistance point to point first and then give you the results in ohms?

[gundee]

Do Not use anti seize on plugs.

If you do get the copper impregnated type.

You must have a good ground path on the threads for plugs.

[jalexquijano]

Well im ready to start. What first? Measure ohms from rotor cap terminal to plug? Then, clean 6 plugs with brass brush and take car for spin after adjusting front carb to 3.75 turns?

[Yarb]

Spraythem down with carburetor spray as well

[Mark Maras]

 I'd clean the plugs before the test. You're looking for high resistance in one or more plug wire circuits. Measure from inside the cap to the center electrode on the sparkplug. Please post the results.

 Although I used liberal amounts of silver anti-seize on sparkplug threads for over 50 years without a problem, I always had that nagging feeling that one could use too much and screw up the electrical continuity between the plug and head. I recently discovered that the nagging feeling was correct. I guess I never used too much. Gundee is correct. Use the copper-colored anti-seize on sparkplug threads and likely it's good for everything else too. I just bought my first can.

[jalexquijano]

23 hours ago, Mark Maras said:

 I'd clean the plugs before the test. You're looking for high resistance in one or more plug wire circuits. Measure from inside the cap to the center electrode on the sparkplug. Please post the results.

 Although I used liberal amounts of silver anti-seize on sparkplug threads for over 50 years without a problem, I always had that nagging feeling that one could use too much and screw up the electrical continuity between the plug and head. I recently discovered that the nagging feeling was correct. I guess I never used too much. Gundee is correct. Use the copper-colored anti-seize on sparkplug threads and likely it's good for everything else too. I just bought my first can.

All plugs cleaned. Took the car for a nice long spin, some time idling during parking waiting to pick up my roasted chicken lunch and then back home. Plugs 1, 2 and 3 results: