NC-car-guy

1954 century sedan. GA to NC

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Alright.  I've been driving it a couple months now and trying to iron out the nit picky parts:

She starts and runs great but there's a couple quirks.   Maybe they are just old Buick quirks, or maybe I need to fine tune.  Hoping some of the experience here will help me narrow it down.

 

1) When started cold, it idles very slow and almost "lobes" but once warmed up it's smooth as silk  but....

2) Once warm, she seems to idle a little too fast.  When I put in D, L or R the car clunks and I better be holding the brake firmly.  I am sure she needs a trans mount, but still seems like it's a little rough!

3) Sometimes after driving for a while, it will idle rough at a stop light.  By rough, I just mean I can feel a little shake in the wheel.  sometimes by the next stop light she'll idle so smooth you barely know it's running, this is so intermittent it's odd

4) She hesitates on take off most of the time.  I have to give the pedal a light feathering to go without a momentary bog down.  There's been a few times where I've touched the pedal though and she zooms off. I'm always surprised when it does.

 

Some factors to consider:

rebuilt fuel pump, all new fuel lines, fuel tank has been cleaned, new fuel filter (checked recently, still clean), new ignition coil, new electric choke

I've cleaned and adjust the points and cleaned and gapped the plugs.  

 

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Might want to put a tach on there and check idle RPM when warm. About 600 is where I set mine. Trans mounts shouldn't have much to do with the way the transmission operates other than the shift lever. Setting fast idle choke will help with the cold starting, but what you described is what my engine does exactly on cold start up and driving around town. It runs good for a good several seconds, then almost starves out then picks up again. This is probably the icing condition of the carburetor, where atmospheric temperatures drop about 50 degrees at the venturi and causes a restriction where the water molecules ice over the walls of the throttle bore and sometimes the plenum. Has it been cold and humid? I don't get these conditions during the summer time. My grandfather said he used to carry a squeeze bottle in the car with gas in it so on cold morning start ups he could squirt a bit more fuel into the carburetor to keep it going until the engine's ambient temperature could melt off the ice.

 

I also run a vacuum gauge in the car. At stop lights, sometimes it'll be high and sometimes it'll be low. A carburetor is mechanically tuned for one ideal scenario whereas modern cars can compensate for changes in pressure, temperature, etc. I can't explain this one, and my vacuum gauge doesn't flutter madly, so I know my rings and valves are ok. I chalked it up as the nature of the beast. You could try replacing the spark plug wires. Do you know if they are solid core or carbon core? The modern plug wires break down over a year or two, maybe longer depending on how old they are and how much the car is driven.

 

I can't remember off the top of my head. Did you rebuild the carb?

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42 minutes ago, Beemon said:

Might want to put a tach on there and check idle RPM when warm. About 600 is where I set mine. Trans mounts shouldn't have much to do with the way the transmission operates other than the shift lever. Setting fast idle choke will help with the cold starting, but what you described is what my engine does exactly on cold start up and driving around town. It runs good for a good several seconds, then almost starves out then picks up again. This is probably the icing condition of the carburetor, where atmospheric temperatures drop about 50 degrees at the venturi and causes a restriction where the water molecules ice over the walls of the throttle bore and sometimes the plenum. Has it been cold and humid? I don't get these conditions during the summer time. My grandfather said he used to carry a squeeze bottle in the car with gas in it so on cold morning start ups he could squirt a bit more fuel into the carburetor to keep it going until the engine's ambient temperature could melt off the ice.

 

I also run a vacuum gauge in the car. At stop lights, sometimes it'll be high and sometimes it'll be low. A carburetor is mechanically tuned for one ideal scenario whereas modern cars can compensate for changes in pressure, temperature, etc. I can't explain this one, and my vacuum gauge doesn't flutter madly, so I know my rings and valves are ok. I chalked it up as the nature of the beast. You could try replacing the spark plug wires. Do you know if they are solid core or carbon core? The modern plug wires break down over a year or two, maybe longer depending on how old they are and how much the car is driven.

 

I can't remember off the top of my head. Did you rebuild the carb?

The car never has an issue starting,  it just idles kinda lobey on cold start.... not cold weather, just meaning first start of the day.  It has not been cold here until today and that's 44 degrees.  I don't know the wire core type and  no I didn't rebuild the carb

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Fast idle on cold starts should be in the 1400 rpm range. Try this. Start the engine cold & keep your foot on the gas for a minute or two in that range. Then back off slowly over the next minute. This will cause the choke butterfly to open more preventing cold start flooding. 

The hesitation you mention is the same lag everyone is mentioning when rebuilding carbs. It is a bear. Solve it and you'll make a lot  friends. It appears to be inherent, and I believe those not bothered by it have just worked around it. But have you put some marvel mystery oil in the oil hole on your distributor advance plate? If not several drops may help. 

As to the plug wires I recommend insulating them under the spark plug covers. I use the black plastic wire loam which is in the automotive electrical section of my local walmart. It has totally eliminated cross firing and has not melted under normal engine heat. I went so far as to pull out the rubber wire separators at the back of the plug covers and in the routing brackets so i could get insulators from the plugs up past the top brackets. It does not look right, but it helps driveability . 

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2 minutes ago, JohnD1956 said:

Fast idle on cold starts should be in the 1400 rpm range. Try this. Start the engine cold & keep your foot on the gas for a minute or two in that range. Then back off slowly over the next minute. This will cause the choke butterfly to open more preventing cold start flooding. 

The hesitation you mention is the same lag everyone is mentioning when rebuilding carbs. It is a bear. Solve it and you'll make a lot  friends. It appears to be inherent, and I believe those not bothered by it have just worked around it. But have you put some marvel mystery oil in the oil hole on your distributor advance plate? If not several drops may help. 

As to the plug wires I recommend insulating them under the spark plug covers. I use the black plastic wire loam which is in the automotive electrical section of my local walmart. It has totally eliminated cross firing and has not melted under normal engine heat. I went so far as to pull out the rubber wire separators at the back of the plug covers and in the routing brackets so i could get insulators from the plugs up past the top brackets. It does not look right, but it helps driveability . 

thanks John.  No problem starting, just curious about the wild difference in idle speed.  I'll try the other suggestions!

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Matt, your symptom mirrors mine exactly. No issue starting, just lopey after a good 30 seconds, then picks up again after a minute. Is NC really humid on the Atlantic coast? Even at 40 degrees, ambient intake temps are still below freezing. Probably just the nature of the beast.

 

Bog is something to live with, though its not as bad with a WCFB as it is with a 4GC (tuned exactly the same, the 4GC stalled a few times at lights for me - never had an issue with the WCFB). There are multiple accelerator pumps available, you could theoretically go and get a bunch and play around with pump shot placement. I would check the product service manual, too, as see if there's anything about changing the step hole on the accelerator linkage, where the C-piece connects the accelerator rod to the pump. John's suggestion about the breaker plate is good, too, as those felt pads can dry up and create friction on the advance plate.

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Yes it's humid here, but I've not driven it in the cold weather yet....  never had it out under 65-70 degree day.  Anyway,  I just know that my little 264 special did not exhibit these symptoms and this car does.  The thrusting into gear is the most worrisome really.

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Replace the motor mounts, you'll be surprised what that will take care of. 

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3 minutes ago, MrEarl said:

Replace the motor mounts, you'll be surprised what that will take care of. 

Hhmmmm

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20 hours ago, wndsofchng06 said:

1) When started cold, it idles very slow and almost "lobes" but once warmed up it's smooth as silk  but....

2) Once warm, she seems to idle a little too fast.  When I put in D, L or R the car clunks and I better be holding the brake firmly.  I am sure she needs a trans mount, but still seems like it's a little rough!

3) Sometimes after driving for a while, it will idle rough at a stop light.  By rough, I just mean I can feel a little shake in the wheel.  sometimes by the next stop light she'll idle so smooth you barely know it's running, this is so intermittent it's odd

4) She hesitates on take off most of the time.  I have to give the pedal a light feathering to go without a momentary bog down.  There's been a few times where I've touched the pedal though and she zooms off. I'm always surprised when it does.

 

Some factors to consider:

rebuilt fuel pump, all new fuel lines, fuel tank has been cleaned, new fuel filter (checked recently, still clean), new ignition coil, new electric choke

I've cleaned and adjust the points and cleaned and gapped the plugs.  

Electric choke?  Who installed and why?  I have never had a problem with the choke except for the heat tube.

Anyhow the stock setup works by depressing the gas pedal to set the choke closed.  Linkage from the choke rotates the fast idle cam under the fast idle adjustment screw (1400rpm).  When the engine starts the choke pull off (that vacuum piston in the choke housing on a WCFB) cracks the choke blade slightly.  Check the exhaust when cold and lopey...if puffing black smoke then the choke is not opening enough (don't know how to fix if electric choke).  If the carb has ever been apart, the reassembly may be wrong:  the gasket between the bowl section and base can be installed 2 different ways (one way is wrong and will not allow vacuum to the choke pull off vacuum piston).  Set the fast idle and base idle and observe the choke with a cold start.  Report back.

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Busy today.  Got the defroster blower motor out and it of course is different that the other one I have here.  Anyhow can't get the shaft unsiezed from the brass bushing.  Moved on to the wiper motor.  Made a tool for it from am old cheap screw driver.  20171112_130213.thumb.jpg.105ad8a09fb3708f90f7033070e47225.jpgCompletely disassembled,  cleaned,  regreased...runs like a champ now. 

Also pulled the starter,  sure enough that freeze plug was my leak. 20171112_152918.thumb.jpg.647c41606668d9595f6b21da57c9c26b.jpg Replaced that and I think putting the starter back on took 4 hours.... not really, but holy crap! 

Edited by wndsofchng06 (see edit history)
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10 hours ago, JohnD1956 said:

Nice!  Details on the wiper fix?

I should've taken photos,  but it was actually easy.  The old grease was just hardened up.  Completely disassembled,  cleaned every piece with degreaser, dried,   lightly greased with some wheel bearing grease and reassembled.   Also replaced all the vacuum lines.  Ad far as tips... the directional control  (hump on front side) does have a spring loaded arm,  be careful.  And the screws to the directional control cover and the switch (top of motor where cable connects) are each unique from the body of the motor and each other.

Edited by wndsofchng06 (see edit history)
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I got the washer pump working this weekend,  unfortunately it seems  I'm losing all my vacuum at the switch.  I forgot what the trick is to getting the wiper switch out, so I'll get back to it later.  Also the horn button appears to be a lost cause for now.  The contact at the bottom of the column feels "chewed up"and I can't see in there so... dash button for now.   I also put a new rubber grommet around the brake pedal shaft... still squeaks!  Ugh!

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3 hours ago, wndsofchng06 said:

 Also the horn button appears to be a lost cause for now.  The contact at the bottom of the column feels "chewed up"and I can't see in there so... dash button for now.

 

Might as well add power steering while the steering shaft is pulled... might as well, might as well...might as well, might as well (sang Jerry Garcia)

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11 minutes ago, MrEarl said:

 

 

 

 

Might as well add power steering while the steering shaft is pulled... might as well, might as well...might as well, might as well (sang Jerry Garcia)

I have everything I need to do that, if I can find where I put it all.  BUT   A, I need a place to be able to lift the car high enough to lower that whole unit out from under it. and B, that's such a big project that takes the car off the road for too long, I'm not real motivated to do it!

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59 minutes ago, wndsofchng06 said:

I need a place to be able to lift the car high enough to lower that whole unit out from under it.

Only underside work is to R&R the pitman arm...otherwise it comes out over the fender.

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3 minutes ago, old-tank said:

Only underside work is to R&R the pitman arm...otherwise it comes out over the fender.

Really?  the firewall cut out for the column is large enough to accommodate that much movement?  :o

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He din't say it was easy, and two sets of hands is a big plus. I generally pull the drivers side fender before pulling the steering sector on my parts cars, but this isn't a parts car is it.

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Just do it...then you are the expert and will wonder what took you so long to decide. :D

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8 hours ago, wndsofchng06 said:

I got the washer pump working this weekend,  unfortunately it seems  I'm losing all my vacuum at the switch.  I forgot what the trick is to getting the wiper switch out, so I'll get back to it later.  Also the horn button appears to be a lost cause for now.  The contact at the bottom of the column feels "chewed up"and I can't see in there so... dash button for now.   I also put a new rubber grommet around the brake pedal shaft... still squeaks!  Ugh!

 

Do you lose vacuum when you press the button or all the time? You can get it out by using a pick to gently pry the button out of the bezel. You'll need special needle nose pliers to unscrew the nut. Then all you have to do is pull the cable through the firewall to get it out. The washer button is just a long needle that pushes a plate against a neoprene washer that's spring loaded on the other side and opens the vacuum circuit to the pump. If there's no leak when the button isn't pressed then don't worry about it. 

 

Did you verify the washer pump isn't a vacuum leak? 

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56 minutes ago, Beemon said:

 

Do you lose vacuum when you press the button or all the time? You can get it out by using a pick to gently pry the button out of the bezel. You'll need special needle nose pliers to unscrew the nut. Then all you have to do is pull the cable through the firewall to get it out. The washer button is just a long needle that pushes a plate against a neoprene washer that's spring loaded on the other side and opens the vacuum circuit to the pump. If there's no leak when the button isn't pressed then don't worry about it. 

 

Did you verify the washer pump isn't a vacuum leak? 

The switch is the leak.  I get slight vacuum at the washer pump without the button pressed.  When I press the button I get only slightly more.  When I bypass the switch I get full vacuum.

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9 hours ago, wndsofchng06 said:

Really?  the firewall cut out for the column is large enough to accommodate that much movement?  :o

Pretty easy to remove front seat, then you have a lot more room without the worry of tearing upolstery. I'm thinkin' you will agree it was a very good idea after first parallel parking event! Check parts book I think pwr streering drag link and pitman arm are part numbered different from manual streering parts. Dang memory! What's shorter than that? Oh yeah!

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