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1964 Thunderbird, 390 FE
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Discussion Starter · #1 ·
My grandpa and I went for quite a drive in the 64 Thunderbird yesterday in the lower 90* Illinois heat. (It was extremely humid as well. - not sure if that matters to the engine or not) It has the original 390 FE, everything stock with the exception of a new vacuum secondary Holley carburetor. I got on the gas for an entrance ramp, heard it start knocking, and immediately took my foot out of it. I drove easy the rest of the day.

Timing is set with timing light at 6* BTDC with vacuum advance unhooked.

We are running no ethanol 89 octane currently. We have access to 93 with ethanol.

Now for the questions...

Do I move to 93 in the summertime when the Tbird is driven and then fill up with the no ethanol 89 before we park it for the winter?
Pull a couple degrees timing?
An octane booster?
Colder heat range spark plugs?

I've been working overtime so it may be a couple days before I can read and comment to your responses, but I will get to them. Thanks in advance.
 

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Move up to 93 octane and see what reaction you get. Deleting timing does help but also costs power and what meager mileage an FE already gets.

These are robust engines from the good old days a little ping won’t hurt them but that said trying to wind them out with ping will.

Not to sure about carbon cleaning this tends to be hard on ring to wall lubrication in my experience is likely to result in bigger problems than in solves.

The auto trans in these is not up to being beat on it cracks a bulkhead on the main case that ruins the transmission.

Bogie
 

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Check the mechanical timing advance and total timing. At what RPM is it all in and what is the total mechanical advance. Maybe the distributor is worn out, maybe just needs heavier springs. Maybe a spring broke. I would check the timing before doing anything else.
 

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you mentioned a recently installed Holley Carb, Do you have the vacuum advance hooked up to manifold or venturi vacuum? If you are using venturi vacuum( off RH side of carb) then the harder you accelerate, the more advance is brought in. If you are using manifold vacuum, then advance is maintained until you accelerate(vacuum drops) then timing retards until vacuum returns.
In order to set base timing, you should know what your total mechanical advance and your vacuum advance is. You can determine these with a timing lamp. Hook up lamp and set intital to 8* with vacuum advance unhooked. Speed up engine and watch timing marks, read the highest reading on the marks and subtract 8* from that. Write that number down as mechanical advance. Next, using manifold vacuum as source, connect vacuum advance and read timing marks, subtract 8* from that and write down as vacuum advance.
Say your numbers were 20 mech, + 6 vacuum + 8 initial = 34 total, which wouldn't be bad. You can change your initial to 10 and hook up vacuum advance to manifold vacuum, this way under acceleration, timing would retard as long as vacuum was low, but advance as you lifted throttle.

I wouldn't do the de-carbon thing, it can cause problems. Plugs, however can get deposits on them that glow from heat and pre ignite.
 

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Discussion Starter · #7 ·
Thanks guys. I will have plenty to do these coming weeknights.
Move up to 93 octane and see what reaction you get. Deleting timing does help but also costs power and what meager mileage an FE already gets.

These are robust engines from the good old days a little ping won’t hurt them but that said trying to wind them out with ping will.

Not to sure about carbon cleaning this tends to be hard on ring to wall lubrication in my experience is likely to result in bigger problems than in solves.

The auto trans in these is not up to being beat on it cracks a bulkhead on the main case that ruins the transmission.

Bogie
Next fill up will be 93 octane. And yes, the 390 doesn't know what economy is, I calculated around 9 mpg around town and a few 55mph highways with only hitting a few stoplights. Also I have taken it easy on the trans thanks to your warning in a previous thread.

The plugs were just cleaned using a plug cleaner the old mechanic we called in to help out had. There was a lot of carbon buildup from running way rich due to a vacuum leak through the PCV valve. I still have a new set of Autolites ready to go in, but right now a pair of vice grips are pinching off the PCV while the new PCV valve is being shipped. My plan was to put in the new valve so everything vacuum-wise was normal before throwing the new plugs in.

you mentioned a recently installed Holley Carb, Do you have the vacuum advance hooked up to manifold or venturi vacuum? If you are using venturi vacuum( off RH side of carb) then the harder you accelerate, the more advance is brought in. If you are using manifold vacuum, then advance is maintained until you accelerate(vacuum drops) then timing retards until vacuum returns.
In order to set base timing, you should know what your total mechanical advance and your vacuum advance is. You can determine these with a timing lamp. Hook up lamp and set intital to 8* with vacuum advance unhooked. Speed up engine and watch timing marks, read the highest reading on the marks and subtract 8* from that. Write that number down as mechanical advance. Next, using manifold vacuum as source, connect vacuum advance and read timing marks, subtract 8* from that and write down as vacuum advance.
Say your numbers were 20 mech, + 6 vacuum + 8 initial = 34 total, which wouldn't be bad. You can change your initial to 10 and hook up vacuum advance to manifold vacuum, this way under acceleration, timing would retard as long as vacuum was low, but advance as you lifted throttle.

I wouldn't do the de-carbon thing, it can cause problems. Plugs, however can get deposits on them that glow from heat and pre ignite.
Vacuum advance is hooked up to venturi vacuum on the carb. I will figure out what the mechanical and vacuum advance is some night this week, hopefully Tuesday.

I see on Vice Grip Garage episodes Derek pours that Berrymans cleaner down the carb of cars that sat for long periods of time. Before I started working on the Thunderbird last summer the last time it ran was 1994... Would that stuff do some good?
 

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I would look to fix the carb first. PCV valve isn't going to make anything run rich and 9 mpg is certainly excessive fuel consumption. Sounds to me like the carb is the root of your problems with buildup of carbon.

Once you have the PCV valve in and the carb fixed, then you can kill the engine (make sure is completely warmed up/hot) by holding to about 1500 rpm and suddenly pouring a pint of whatever top engine cleaner (they are all petroleum distillates) you choose down BOTH primary venturis of the carb. Let it sit for 30 minutes and then crank until it starts again. Don't over rev the old beast or beat it badly, but you can do some spirited driving while blowing out the soaked/loosened carbon. Another can of cleaner in 1/2 gas tank (of follow directions) and then drive it out. Don't put excess cleaner in the fuel system - it swells rubber hoses and other stuff horribly. Don't ask how I know.

Then finally change to your new spark plugs.
 

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That's nice to hear you've got the old Bird out for a cruise. As you wrote it's all stock so you've also got the ignition points to set. Your in great shape though with the timing gear sets if you ever need one, the '64 will take a double roller. The Holley on our old Chrysler has lots of adjustments, maybe not the same model as yours. We rolled the choke pull-off cap back as quick as it would go without damaging the carb. With it set like that, in 40-50 degree weather it'll stumble all over the place until starting to warm up. And the front squirter level rod thingy cannot be activated while idling or it will mess up the shot when you step on the gas. Finally, we adjusted the screws with a vacuum gauge for highest vacuum reading, a method some do not like, and then equally richened each screw a 1/4 turn or slightly less. Not to mention the colored cam adjustment on the side of the carb as well as the secondary circuit activation rod adjustment.

If your running points ignition you might want to look at building your own solid core ignition wires, might screw with your bluetooth, though.

I'd drain the tank at the end of the season and use it in the snowblower.

Let us know how the timing turns out if you get a chance.
 

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Discussion Starter · #10 ·
I would look to fix the carb first. PCV valve isn't going to make anything run rich and 9 mpg is certainly excessive fuel consumption. Sounds to me like the carb is the root of your problems with buildup of carbon.

Once you have the PCV valve in and the carb fixed, then you can kill the engine (make sure is completely warmed up/hot) by holding to about 1500 rpm and suddenly pouring a pint of whatever top engine cleaner (they are all petroleum distillates) you choose down BOTH primary venturis of the carb. Let it sit for 30 minutes and then crank until it starts again. Don't over rev the old beast or beat it badly, but you can do some spirited driving while blowing out the soaked/loosened carbon. Another can of cleaner in 1/2 gas tank (of follow directions) and then drive it out. Don't put excess cleaner in the fuel system - it swells rubber hoses and other stuff horribly. Don't ask how I know.

Then finally change to your new spark plugs.
It was my understanding that the PCV valve caused a vacuum leak enough to open the power valve. It was loading up pretty bad and smoking quite a bit previously. Once the old mechanic had me pinch off the PCV hose it stopped smoking. Then we slowed down the idle and adjusted the mixture screws and it was as smooth as can be Sunday.

Tonight after some family cruised around during the day the idle speed raised to 1100 rpm, so I lowered it back down again tonight and leaned out the idle mixture screws and the rpm raised more. I lowered it again to 800 in park and 600 in gear. I'm not sure what changed. I didn't get to the timing tonight, but should tomorrow. The choke is set to the leanest setting right now.

I will see what the fuel economy is now that I leaned the idle more.

seven up, the points are set to .017 and the dwell is within spec. We bought new plug wires after hearing arcing, but I don't recall the type. We didn't cheap out, but didn't get super expensive ones...

Thanks to all.
 

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The lever requires a very slight space between it and the red spring. The exact measurements for the spacing on the squirter is probably on the Holley site. In other words, the squirter lever cannot be engaged while your at idle. I've adjusted these in the past and months later it was out of adjustment again. Same thing with the idle mixture screws. I hope you have better luck.

Do you have the Autolite 4100 ? The 1.12 venturis are more common but still bring a nice price.
 

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You need to observe the choke these old FE’s carbon up the crossover under the intake which cuts off the heat supply that the choke’s bimetallic spring needs for operation. Another common problem related to this is the air tube inside the exhaust crossover that supplies heated air to the choke rots out then the choke thermostat feeds on exhaust gasses which makes a big mess inside the cover as exhaust gases are quite corrosive.

Bogie
 

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It was my understanding that the PCV valve caused a vacuum leak enough to open the power valve. It was loading up pretty bad and smoking quite a bit previously. Once the old mechanic had me pinch off the PCV hose it stopped smoking. Then we slowed down the idle and adjusted the mixture screws and it was as smooth as can be Sunday.

Tonight after some family cruised around during the day the idle speed raised to 1100 rpm, so I lowered it back down again tonight and leaned out the idle mixture screws and the rpm raised more. I lowered it again to 800 in park and 600 in gear. I'm not sure what changed. I didn't get to the timing tonight, but should tomorrow. The choke is set to the leanest setting right now.

I will see what the fuel economy is now that I leaned the idle more.

seven up, the points are set to .017 and the dwell is within spec. We bought new plug wires after hearing arcing, but I don't recall the type. We didn't cheap out, but didn't get super expensive ones...

Thanks to all.
What happens if you continue to close the idle mixture screws? Does engine slow down before they reach their seat? It should. Idle mix should be the max RPM first obtained, as you turn the mix screws back out after slowing the engine down this way.
 

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Discussion Starter · #14 ·
The lever requires a very slight space between it and the red spring. The exact measurements for the spacing on the squirter is probably on the Holley site. In other words, the squirter lever cannot be engaged while your at idle. I've adjusted these in the past and months later it was out of adjustment again. Same thing with the idle mixture screws. I hope you have better luck.

Do you have the Autolite 4100 ? The 1.12 venturis are more common but still bring a nice price.
I will look at the lever thing. I still have the Autolite 4100, but one of the mixture screws is really stuck. That is the reason we bought the Holley to begin with.

What happens if you continue to close the idle mixture screws? Does engine slow down before they reach their seat? It should. Idle mix should be the max RPM first obtained, as you turn the mix screws back out after slowing the engine down this way.
Yes, The engine slows down when I close them, and I did tune for highest rpm after closing them.

You need to observe the choke these old FE’s carbon up the crossover under the intake which cuts off the heat supply that the choke’s bimetallic spring needs for operation. Another common problem related to this is the air tube inside the exhaust crossover that supplies heated air to the choke rots out then the choke thermostat feeds on exhaust gasses which makes a big mess inside the cover as exhaust gases are quite corrosive.

Bogie
I am not sure I understand what you are getting at. The new Holley has electric choke. The old Autolite had a coolant hose up against the choke spring which my grandpa and I believed was what heated up the choke to make it release.

I looked at the timing again tonight, and initial is at 10* :unsure: hmmmm. The distributor must have been bumped. I attempted to see how much mechanical and vacuum advance there was, but aside from a couple ticks around the white mark I made for the 6* tick, the rest of the balancer is unreadable while running, and still extremely hard to read when stopped. I ran out of time, so I didn't adjust the timing, just backed in the garage.
 

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No problem. Good to know if we ever go back to the original one.
I've gotten a couple of those loosened up. Idle mixture screws and secondary butterfly shaft. Doused the mixture screw outlet with penetrant and stood the carb on end for a couple of days. Warmed it up with a hair dryer, not hot enough to burn yourself, let it come down to room temp then into a freezer. I've saw that computer cleaner spray works too, for freezing. You just can't twist the screw into oblivion figuring it'll be loose. On one carb and exhaust manifold the cycle had to be repeated a few times for success.

From your earlier posts it looks like you've got variable valve timing. 6 then 10. If you've verified a good condition distributor, the timing chain slack can be checked by removing the two fuel pump bolts and give it a prodding(the chain slack). Your lucky though, you can still cruise around while being sorted out.
 

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I will look at the lever thing. I still have the Autolite 4100, but one of the mixture screws is really stuck. That is the reason we bought the Holley to begin with.
This video is interesting in that it briefly talks about the squirter in relation to activation of the secondaries(at 4:00 minutes).


Accelerator Pump - YouTube
 

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Doesn't seem like it is running too rich anymore, at least at idle and carb isn't flooding through a power valve leak.

I had a 390 FE in a 67 Galaxie with a pretty large cam, Holley 3310, headers, intake, and a centrifugal only distributor. It was still able to get 17 mpg on average. Bothers me that you only get 9 mpg.
 
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