1966 390 Carb issues

[pentium]

Hey there! Figured I would give a brief history of my Thunderbird. I am 28 years old and since a young child, I gravitated towards Ford vehicles and they're all I've ever owned.
My Grandfather, who I was close with bought this 66 Thunderbird in 1971 from the original owner. It was his daily driver until 1986 when he retired. He had a short commute, so it has low miles. It was re-painted the original color in 1989 and has been in a garage or a hangar ever since. I know that the mileage on the car was 98,000 in 2000 because of a kept car show banner. Everything except the paint job is completely original.

Unfortunately, my grandfather passed away in 2018 at the age of 93. His mind was still sharp, and he told me that he wanted me to have the Thunderbird (He had lots of cars but knew I was a Ford guy and wanted to give it to me.)

When I was able to get moved into a place with a garage where I was able to store it, I went down to get it and it had 101,492 miles. So, lots of sitting for 18 years. Hooked a battery up to it, put in some gas and it started right up.

Things that needed to be fixed immediately: failed master break cylinder, freeze plugs, tires, gaskets, gearbox
I had all that work done (every gasket replaced including carb gasket, plugs, gearbox, master break cylinder, shift column spring, new tires, got the transmission rebuilt). The issues left are: partial working turn signals, gas gauge always reads E, carb needs to be tuned about every 10-15 miles.

I want to get the carb working first. The thing has caused me lots of headaches (literally) because I will lean out the mixture, go for a drive and it will be running very rich again by the time I get home. To the point where when I park it in the garage, I will wake up the next morning and my entire condo will smell like gasoline. When adjusting the timing screw, I make very minor adjustments. No matter what I do, it will run well for about 10 miles and then start acting funny. My uncle told me that he rebuilt it (most likely in the 90s)

I posted some pictures of the carb, the original 4 barrel 4100. I was planning on putting in a brand new Edelbrock. Talking to car friends, half say it's a great idea, some say to keep it original. The most important thing to me, is having it run reliably. Even if it's not 100% original, I just want it to run well because I love driving the car. It's no fun when I go for a quick stop and then the motor won't start. Is going to a new Edelbrock a bad idea? I was thinking a 600cfm would do great on this thing.

The engine runs healthy, but my Uncle who grew up with the car said that the rings will need to be replaced in 5-10 years. When it's running okay, it gets 7-10MPG. Has a nice low rumble, but when sitting in Park or Neutral, you will here an occasional quick "POP" in the exhaust.

I really appreciate any thoughts, comments, opinions. Thank you!

 

[inspector]

That's a fine looking Bird you have there. Don't be shy, show us more pictures. I had the same problems with my carb. Spent all kinds of time fiddling and diddling with it to no avail. Finally bought a carb kit and rebuilt it. Works fine now. If your mechanically inclined you can do it your self. Keep the 4100. Its a good carb.

 

[Dlluinstra]

Holley Sniper EFI.

 

[biddle]

Don't be shy, show us more pictures.

Just make sure you post them in the media gallery-

Browse Ford Thunderbird albums

forums.fordthunderbirdforum.com

 

[Seabird]

Congratulations! Definitely a looker; add my vote for more pix. The carb decision you make should be based on how much more playing and modification you want to do on your family car. Once you move to Holley or Edelbrock you will be bound to start changing more and more things. Pertronix will come next, then an electric choke, lowering blocks, just joking. The 4100 is a superior instrument for that car and yours has just sat still too long. Professionally rebuilt it will match any other. So, do you want to drive that car or tinker?

Plus, my soapbox for all new 4500 lb. Bird owners, get on those old brakes now. At the very least, 3 rubber lines gotta go. It's a great car. Good luck!

 

[Douglemmo]

Hi,
You have an Autolite carburetor which is correct for the period and is an excellent carburetor. In any event, take it to someone who works on these, and there are many people who do, and get it rebuilt and adjusted properly. There is no reason that this carb. shouldn't work perfectly for you. You could do it yourself as there are plenty of kits available, but unless you have done a few rebuilds, spend the money and get a reliably running car. Given your note above, I would suggest not driving the car until yo get it sorted out. Given what you have said, if that carb starts leaking gas onto the engine, a new carb will be the least of your problems.

It is a nice looking car. Good Luck with it.

 

[jack-in-sac]

Hey there! Figured I would give a brief history of my Thunderbird. I am 28 years old and since a young child, I gravitated towards Ford vehicles and they're all I've ever owned.
My Grandfather, who I was close with bought this 66 Thunderbird in 1971 from the original owner. It was his daily driver until 1986 when he retired. He had a short commute, so it has low miles. It was re-painted the original color in 1989 and has been in a garage or a hangar ever since. I know that the mileage on the car was 98,000 in 2000 because of a kept car show banner. Everything except the paint job is completely original.

Unfortunately, my grandfather passed away in 2018 at the age of 93. His mind was still sharp, and he told me that he wanted me to have the Thunderbird (He had lots of cars but knew I was a Ford guy and wanted to give it to me.)

When I was able to get moved into a place with a garage where I was able to store it, I went down to get it and it had 101,492 miles. So, lots of sitting for 18 years. Hooked a battery up to it, put in some gas and it started right up.

Things that needed to be fixed immediately: failed master break cylinder, freeze plugs, tires, gaskets, gearbox
I had all that work done (every gasket replaced including carb gasket, plugs, gearbox, master break cylinder, shift column spring, new tires, got the transmission rebuilt). The issues left are: partial working turn signals, gas gauge always reads E, carb needs to be tuned about every 10-15 miles.

I want to get the carb working first. The thing has caused me lots of headaches (literally) because I will lean out the mixture, go for a drive and it will be running very rich again by the time I get home. To the point where when I park it in the garage, I will wake up the next morning and my entire condo will smell like gasoline. When adjusting the timing screw, I make very minor adjustments. No matter what I do, it will run well for about 10 miles and then start acting funny. My uncle told me that he rebuilt it (most likely in the 90s)

I posted some pictures of the carb, the original 4 barrel 4100. I was planning on putting in a brand new Edelbrock. Talking to car friends, half say it's a great idea, some say to keep it original. The most important thing to me, is having it run reliably. Even if it's not 100% original, I just want it to run well because I love driving the car. It's no fun when I go for a quick stop and then the motor won't start. Is going to a new Edelbrock a bad idea? I was thinking a 600cfm would do great on this thing.

The engine runs healthy, but my Uncle who grew up with the car said that the rings will need to be replaced in 5-10 years. When it's running okay, it gets 7-10MPG. Has a nice low rumble, but when sitting in Park or Neutral, you will here an occasional quick "POP" in the exhaust.

I really appreciate any thoughts, comments, opinions. Thank you!
View attachment 11038View attachment 11039View attachment 11040View attachment 11041View attachment 11042

Three items. First Since you are likely keeping the car, get a shop manual. It is a bargain for the information provided. Second; carburetor; The Autolite 4100 is a very reliable carburetor. It is simple and it works. It also stays in tune for a very long time once it is set. Third Since the car has had a lot of sitting time and the gas gauge doesn't read above empty there are two things I would look at after I make sure that the wiring is good for the sender and gauge, does the temp gauge reflect actual temperature? I do not know when Ford stopped using a small voltage regulator for the temp and gas gauges. A wiring diagram will tell you. If the regulator goes bad the gas goes to empty and the temp goes to hot. This small regulator is on the rear of the instrument cluster and difficult to see. A second thing is that with a lot of sitting the float mechanism can sink and not respond. the float can pinhole and fill up with fuel and not be able to rise. If you have not done it yet, consider having the gas tank "boiled out" to remove sludge and varnish. i am envious of your Bird. Have fun.

 

[Bond007]

What a great car! I love the story. I have an all original 1975 that I plan to give to my grandson. My personal opinion is that your best route would be to get a new modern carburetor. If you should go that route, keep the original carburetor in case you want to go back to all original at some point.

 

[pentium]

That's a fine looking Bird you have there. Don't be shy, show us more pictures. I had the same problems with my carb. Spent all kinds of time fiddling and diddling with it to no avail. Finally bought a carb kit and rebuilt it. Works fine now. If your mechanically inclined you can do it your self. Keep the 4100. Its a good carb.

This is great to hear. I'm not very savvy, so I believe rebuilding the current one would be easier for me than putting on an aftermarket unit. Is yours also a 66 with the 390?

Holley Sniper EFI.

I did some searching on that. Very intriguing, I didn't even know that was possible. What's your experience with that?

Just make sure you post them in the media gallery-

Browse Ford Thunderbird albums

forums.fordthunderbirdforum.com

Will do!

Congratulations! Definitely a looker; add my vote for more pix. The carb decision you make should be based on how much more playing and modification you want to do on your family car. Once you move to Holley or Edelbrock you will be bound to start changing more and more things. Pertronix will come next, then an electric choke, lowering blocks, just joking. The 4100 is a superior instrument for that car and yours has just sat still too long. Professionally rebuilt it will match any other. So, do you want to drive that car or tinker?

Plus, my soapbox for all new 4500 lb. Bird owners, get on those old brakes now. At the very least, 3 rubber lines gotta go. It's a great car. Good luck!

Thank you! It's very fun driving it around and seeing peoples' reactions. I don't want to do a whole lot of modifications to it, I want to be able to drive it without worries. Of course, I want to do was is required to keep the car healthy and keep it in good shape.

I talked to my Uncle again who rebuilt it. He said that he converted the choke to electric. Here is what he said verbatim: "I converted it to electric. It's the round black plastic item with the red connector that I installed. Think it has the thermal switch and heater element in it that gets power from alternator secondary windings. Power only to choke heater when engine is running. Original choke heater was engine exhaust or water heater hose that ran next to choke."

Hi,
You have an Autolite carburetor which is correct for the period and is an excellent carburetor. In any event, take it to someone who works on these, and there are many people who do, and get it rebuilt and adjusted properly. There is no reason that this carb. shouldn't work perfectly for you. You could do it yourself as there are plenty of kits available, but unless you have done a few rebuilds, spend the money and get a reliably running car. Given your note above, I would suggest not driving the car until yo get it sorted out. Given what you have said, if that carb starts leaking gas onto the engine, a new carb will be the least of your problems.

It is a nice looking car. Good Luck with it.

My neighbor is a little older than I am and said he is familiar with carbs. He mentioned that he would help me with whatever route I want to go.
How does this kit look? I think I may want to rebuild the current one and I can always go aftermarket later if I want to. https://www.carburetor-parts.com/Autolite-4100-Carburetor-Kit--Premium_p_2522.html

Funny you mention it. The carb was dumping gas onto the engine. I forgot that the original throttle lever was cracked, so I believe that is what was causing the issue. It's been replaced but I've only driven it 2 miles since it's been replaced.

Three items. First Since you are likely keeping the car, get a shop manual. It is a bargain for the information provided. Second; carburetor; The Autolite 4100 is a very reliable carburetor. It is simple and it works. It also stays in tune for a very long time once it is set. Third Since the car has had a lot of sitting time and the gas gauge doesn't read above empty there are two things I would look at after I make sure that the wiring is good for the sender and gauge, does the temp gauge reflect actual temperature? I do not know when Ford stopped using a small voltage regulator for the temp and gas gauges. A wiring diagram will tell you. If the regulator goes bad the gas goes to empty and the temp goes to hot. This small regulator is on the rear of the instrument cluster and difficult to see. A second thing is that with a lot of sitting the float mechanism can sink and not respond. the float can pinhole and fill up with fuel and not be able to rise. If you have not done it yet, consider having the gas tank "boiled out" to remove sludge and varnish. i am envious of your Bird. Have fun.

Are you referring to something like a Chilton's manual? I believe I have the original manual somewhere in a box too.
I'm glad to hear so many positive things about this carb!
Thanks for the informative answer. The temp guage works accurately, the only gauge that doesn't work is the gas one.

What a great car! I love the story. I have an all original 1975 that I plan to give to my grandson. My personal opinion is that your best route would be to get a new modern carburetor. If you should go that route, keep the original carburetor in case you want to go back to all original at some point.

Thank you! I'm sure your grandson will be very happy about that

 

[Tbird Rich]

I know a lot say rebuild the 4100 but I had a Holley 600 cfm installed last year and could not be happier with it..Mine was not the original anyway ..Never ran so well or started so easy..Good luck..

 

[biddle]

I know a lot say rebuild the 4100 but I had a Holley 600 cfm installed last year and could not be happier with it..Mine was not the original anyway ..Never ran so well or started so easy..Good luck..

I've read this same thing MANY times on the forum! Example- https://forums.fordthunderbirdforum.com/threads/64-flairbird-carb-question.8067/post-51153 I would be willing to bet the people with the Autolite would be happy if they switched the carb to a Holley 600.

 

[64ZCODE]

I'd say the carb is toast. Hence the popping when idling and possibly cause of the strong gas smell (assuming gas isn't dumping on the engine or on the ground from a leak somewhere). Re: the gas smell, check the oil to make sure that the carb hasn't been putting a lot of gas down into the crankcase. Probably good to change the oil on general principles after you've put a new carb on the car. You could try rebuilding the carb but new ones aren't that expensive. I'm running a Holley 670 CFM carb on my '64 and the engine loves it. You should be able to get 12 mpg pretty consistently, especially if you have electronic ignition and the timing is set correctly. A free flowing air filter helps with mileage too.

 

[Tbird Rich]

When I had my carb changed I told my mechanic I am now only getting 12 MPG, had been getting 9 or 10 before..He says well thats about 20% better and I say you are right!!!..Did not look at it that way which really is a great improvement..Not that I care that much about MPG cause dont drive everyday but its good to know..I do have electronic ignition but original air filter housing..Maybe I should change that but like the original look..

 

[64ZCODE]

One of our forum members runs a circular free flowing air filter most of the time, and keeps the original snorkel housing filter to put on the car when at car shows. The problem with the original filter housing is it seems to have been cleverly designed to deprive the engine of air for combustion, what with the tiny snorkel and undersized filter element.

 

[Tbird Rich]

One of our forum members runs a circular free flowing air filter most of the time, and keeps the original snorkel housing filter to put on the car when at car shows. The problem with the original filter housing is it seems to have been cleverly designed to deprive the engine of air for combustion, what with the tiny snorkel and undersized filter element.

If I did use the circular free flow would it change anything ? Would I need any carb adjustments? It runs well now and dont want any headaches..Thanks..

 

[64ZCODE]

The idle mix may need to be adjusted since the volume of air entering the carb will be greater. That's pretty easy and is something that should be done periodically anyway. Hook up a vacuum gauge to manifold vacuum and with engine warmed up adjust the idle mix screws incrementally by the same amount to obtain maximum vacuum at idle.

 

[Tbird Rich]

The idle mix may need to be adjusted since the volume of air entering the carb will be greater. That's pretty easy and is something that should be done periodically anyway. Hook up a vacuum gauge to manifold vacuum and with engine warmed up adjust the idle mix screws incrementally by the same amount to obtain maximum vacuum at idle.

Thanks..Will look into it when all this crazy stuff is over..Hope it is soon..Hope you and yours are doing well...

 

[64ZCODE]

Yes, doing well. Very fortunate throughout all of this virus stuff. Spending a lot of time on Zoom web meetings, it's reminding me of when I was in the working world. We're lucky we have our TBirds and other pursuits to occupy and add fun to our lives, no?

 

[ak7an]

I really enjoyed you sharing your story about your Grandfather and the TBird. You have a beautiful car that will give you great service and more importantly great memories.
While I have no experience with carbs and the 390, I do have the MSD Atomic EFI on the 351W Stroker in my 1964. It works excellent, starts on the first or second TDC when the engine is cold. Warm engine it starts right up if you give the accelerator about 1/4 inch. Fuel mileage is around 14, I was hoping for a little more, but these are big heavy cars and it takes a lot to push them down the road.

 

[64ZCODE]

I have a stock 351W in a Galaxie I own and it's a great motor. I've often thought it would well in a TBird. Lots of low end torque and probably lighter than the 390 by 100 pounds or so.