1966 runs rough, hard to start

B
Last seen
Joined
Jun 4, 2024
Thunderbird Year
1966
I recently purchased car and it was running great but not very rough and hard to start. I have done some testing and found that when running the first spark plug on front of engine on passenger side is not firing. I replaced the plug and still nothing. When idling there is fire coming from the top of distributor but not getting to the plug. I even swapped wires from another cylinder and still nothing. I am no mechanic but when I disconnect the other 7 at idle engine even gets worse but not this first one. Yet I swapped the plug and wire and still nothing. Any help?
 

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I recently purchased car and it was running great but not very rough and hard to start.
Please follow the posting promps moving forward. "1966 Ford Thunderbird" is not a ahort summary of what your topic is about. I have revised your title.

model-year.jpg
 
Do you know how many miles are on the engine?
 
Probably 165, I would do a compression check first. It could be a burnt valve or sticking valve as well.
 
Probably 165, I would do a compression check first. It could be a burnt valve or sticking valve as well.
I am no mechanic. How do you do a compression test?
 
It's quite easy really, head over to your local parts store and buy (or rent) a compression gauge. Remove all spark plugs. Screw compression gauge into numerous one. With throttle wide open crank engine over.stop after the third compression hit. Read and record the gauge. Zero it out and move to number two. Repeat until all are done. Please report your results back.
 
I recently purchased car and it was running great but not very rough and hard to start. I have done some testing and found that when running the first spark plug on front of engine on passenger side is not firing. I replaced the plug and still nothing. When idling there is fire coming from the top of distributor but not getting to the plug.
Since you stated that when idling there is fire coming from the top of distributor but not getting to the plug, did you replace the distributor cap and rotor like mtnbikerx suggested? The fire, as you called it, is the spark arcing across the distributor cap and not getting to the spark plugs. This would definitely cause the rough running condition that you are having.

Repair the obvious first before performing a compression test.

doug7740
1955 Thunderbird Blue
 
Thanks! I have ordered a distributor cap and rotor annd should be in Saturday . Didn’t order points though.
 
Since you stated that when idling there is fire coming from the top of distributor but not getting to the plug, did you replace the distributor cap and rotor like mtnbikerx suggested? The fire, as you called it, is the spark arcing across the distributor cap and not getting to the spark plugs. This would definitely cause the rough running condition that you are having.

Repair the obvious first before performing a compression test.

doug7740
1955 Thunderbird Blue
I put the distributor cap on but the rotor didn't come in. Did not seem to make any differenceand still very rough. I have a compression tester on the way also. I did notice today however the lots of blue smoke coming out of the exhaust. Any ideas on what is causing the smoke?
 
Blue smoke is oil. I think a compression test will answer a lot of questions
 
It's quite easy really, head over to your local parts store and buy (or rent) a compression gauge. Remove all spark plugs. Screw compression gauge into numerous one. With throttle wide open crank engine over.stop after the third compression hit. Read and record the gauge. Zero it out and move to number two. Repeat until all are done. Please report your results back.
With the ignition coil lead DISCONNECTED !!
 
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