Two dead cylinders on a 59ab

[38 coupe]

Cylinders 2 and 1 respectively connect to different sides of the carburetor, with individual passages at the end of the engine. I doubt there is a carburetor problem since all other cylinders are firing, and I doubt a blockage since the compression was good. I too suspect an ignition problem, but diagnosing from the internet is chancy at best.
I had a similar situation once with a 37 Ford and ended up diagnosing it by pulling all eight plugs, reconnecting the plug wires with the plugs sitting on the heads where they would get a decent ground, turning the ignition on, and using a socket wrench to rotate the crank while watching for spark at each plug in order. In my case the point cam in the distributor was machined off center and the spark got very weak for cylinders 1 and 2 since the points were barely opening. I haven't seen or heard of similar before or since, Ford's manufacturing tolerances are usually pretty good.

[glennpm]

Originally Posted by 38 coupe

Cylinders 2 and 1 respectively connect to different sides of the carburetor, with individual passages at the end of the engine. I doubt there is a carburetor problem since all other cylinders are firing, and I doubt a blockage since the compression was good. I too suspect an ignition problem, but diagnosing from the internet is chancy at best.

I would also discount that it is a carburetor problem.

I don't agree about the compression test indicating that there is no blockage though. The compression test shows how well the block, valves and rings are sealing. The volume being tested, does not test the intake manifold.

Originally Posted by 38 coupe

I had a similar situation once with a 37 Ford and ended up diagnosing it by pulling all eight plugs, reconnecting the plug wires with the plugs sitting on the heads where they would get a decent ground, turning the ignition on, and using a socket wrench to rotate the crank while watching for spark at each plug in order. In my case the point cam in the distributor was machined off center and the spark got very weak for cylinders 1 and 2 since the points were barely opening. I haven't seen or heard of similar before or since, Ford's manufacturing tolerances are usually pretty good.

This is good and can be checked either as you mention or by pulling the distributor and the cap. Check the left, driver's side points and see what the gaps look like when rotating CCW from terminal #7 and then on to #2 and then #1.

[Planojc]

Originally Posted by Ggmac

Is there a vacuum fitting between those cylinders on the intake for the distributor brake or windshield wiper ?

The vacuum fitting is on the driver side, have a vacuum gauge on the wiper port.

[richard crow]

remove spark plug #1 get piston t.d.c charg cyl with air lisen for leakage in intake manifold or crankcase do same on cyl 2.

[34fordy]

I am sure this could drive a guy half nuts but I gotta say, I wish I had it in my little shop as it would be a fun project to conquer! When the light goes on you will be SO happy!

[Ggmac]

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Bad spark plugs ? Switch if not a new problem. I know you said good spark to electrodes, but they may fail under compression.

[glennpm]

Originally Posted by Planojc

New coil, Distributor and Carb from Charlie NY, new plugs and plug wires on a 59AB. All cylinders have good compression at about 110. Number one and two cylinders show no change when plugs are shorted to ground. Both are getting hot spark to the plugs and through the plugs to the electrode. It acts like no fuel is making its way to the intake valves on those two cylinders. The valves on both cylinders are clean and are opening and closing like they should as seen with a borescope camera. Short of removing the intake, does anyone have any suggestions? I'm running out of options

Number one and two cylinders show no change when plugs are shorted to ground. Both are getting hot spark to the plugs and through the plugs to the electrode

[Ggmac]

Plugs can spark nicely in atmosphere but fail under compression

[Willit Stop]

#2 and #1 are adjacent in the firing order. A clue maybe. I don't know. Just food for thought.

[hueyhoolihan]

Originally Posted by Ggmac

Plugs can spark nicely in atmosphere but fail under compression

it's just such a troubling thought that i just HAD to double check. it appears it's true, as you say...smh.

and just when i thought i held a fundamental truth in my hands, a rock on which to build my church, it all falls asunder...

[Ggmac]

Originally Posted by hueyhoolihan

it's just such a troubling thought that i just HAD to double check. it appears it's true, as you say...smh.

and just when i thought i held a fundamental truth in my hands, a rock on which to build my church, it all falls asunder...

Learned that along time ago when I was wrenching in a pit crew for a A / altered . I insisted the plugs were good and proceeded to show the boss , boy , I’ll never forget that lesson.
He taught me another good one . You know everyone says you need gas , spark , and compression for it to run ? But when I said that to him he calmly showed me how you can have the three but still not run . What , yup . He loosened the exhaust rocker arm ,unknown to me , then instructed me to take compression, check for spark and check for fuel , which all were present but no go . It would not run . You need flow ie exhaust.
He was a sharp diagnostic specialist.

[Planojc]

Today I'm going to change out the distributor and see what happens.

[35fordtn]

Removed

[rockfla]

Originally Posted by Ggmac

Plugs can spark nicely in atmosphere but fail under compression

At the start of this thread I was going to suggest "maybe" swapping plugs from a "known" good pair of cylinders and putting 1 & 2 in the known good cylinders and see what happens!!!!

[Ggmac]

Originally Posted by rockfla

At the start of this thread I was going to suggest "maybe" swapping plugs from a "known" good pair of cylinders and putting 1 & 2 in the known good cylinders and see what happens!!!!

Good suggestion but we didn’t hear back from the op

[glennpm]

Yes, good sugestion but note that those two plugs are dry.

"Planojc
Quote:
Originally Posted by glennpm View Post
Plugs wet or dry?
Plugs are dry."

[rockfla]

Originally Posted by glennpm

Yes, good sugestion but note that those two plugs are dry.

"Planojc
Quote:
Originally Posted by glennpm View Post
Plugs wet or dry?
Plugs are dry."

Glenn
Yes, the OP in the OP stated that the valves in both cylinders "are opening and closing" SO based on that......THE ONLY logical conclusion that I can formulate in my pea sized brain is in the Intake manifold/or maybe the gasket is compromised??.....AS I know of NO carburetor that can "selectively" supply fuel (or NOT) on a "per cylinder" bases AND select those particular cylinder from the fire cylce?? OR am I missing something?? A real mystery, wrapped in secrecy, surrounded by an enigma

[Bored&Stroked]

Did the problem with #1 and #2 exist BEFORE the new coil and distributor was installed? Or did you put these new components on to attempt to fix it?

[Planojc]

Update, Today I changed out the crab distributor, condenser and cap and I now am running on all 8, with steady vacuum and the car doesn't shake. still clueless on to what is going on with the distributor, but plan on sending it off to be checked. Thanks for all the inputs.

[rockfla]

[QUOTE=Planojc;2415794]Update, Today I changed out the crab distributor, condenser and cap and I now am running on all 8, with steady vacuum and the car doesn't shake. still clueless on to what is going on with the distributor, but plan on sending it off to be checked. Thanks for all the inputs.[/QUOTC


Can you fill Us in a little more....Was this the "Same" rotor as when you were having the issue?? OR did you use a "different" rotor on the replacement distributor to make it run correctly??