1941 Buick Limited Limousine

[Den41Buick]

I moved the starter switch from the pedal to a button under the dash. Solved all my starting issues on both my 41's. No more flooding issues.

 

 

[neil morse]

Matt, I'm sorry to hear that you are experiencing a rough patch.  I'm sending you a PM with some thoughts.

 

Neil

[Lawrence Helfand]

16 hours ago, Den41Buick said:

I moved the starter switch from the pedal to a button under the dash. Solved all my starting issues on both my 41's. No more flooding issues.

 

 

It sounds counter intuitive but the best way to start a flooded engine is to hold the pedal to the floor on any carburetor'd car. Thats how I was taught 55 years ago and its worked countless times to clear the chambers and light her up! I do believe Matt has long ago disabled his foot start for a push button. Thats never the problem if set up is correct and was the standard in many vehicles for many years. Downside to an integrated foot start is the occasional grind when lack of vacuum at close to stall but still running rpm allows starter engagement.    

[Matt Harwood]

My car has a button under the dash. I repaired, then disabled, the foot pedal switch after discovering that it made the car harder to start, not easier. I know that putting your foot on the floor is the right way to clear flooding. In Cincinnati when it just wouldn't start, I was only able to get it running by standing next to it and holding the chokes wide open while Melanie cranked it. Then it fired quickly. It was the chokes causing the problem. I get my Cadillac CTS back tomorrow so I don't have to drive the Limited anymore--the heater isn't great and it's 22 degrees and a veritable snowstorm today. The rush hour drive home in a blizzard will surely be exciting.

 

To get it started each morning in the cold the last few weeks, I've simply not touched the throttle--the chokes are open from my previous drive so it fires pretty easily. The instant those chokes close, it just won't start in the cold. Several times I had to prop the chokes open with a pen to get it to fire. This seems counter-intuitive to me, because I would think that it would like more choke for the cold, but it just fights me. I have the chokes set very loose given that I have two of them and ostensibly it was intended for warm weather use only. I don't expect to do much more winter driving so I'm not too worried about it (it still starts instantly when it's above about 50 degrees), but it sure was frustrating in Cincinnati to miss most of the tour because it was inop. I don't have the fortitude to screw with it anymore, so it's as good as it's going to get. I don't care enough anymore to chase little details like this. If it's good in the spring and summer, that's good enough.

[Ben Bruce aka First Born]

2 hours ago, Lawrence Helfand said:

It sounds counter intuitive but the best way to start a flooded engine is to hold the pedal to the floor on any carburetor'd car. Thats how I was taught 55 years ago and its worked countless times to clear the chambers and light her up! I do believe Matt has long ago disabled his foot start for a push button. Thats never the problem if set up is correct and was the standard in many vehicles for many years. Downside to an integrated foot start is the occasional grind when lack of vacuum at close to stall but still running rpm allows starter engagement.    

 

 I may not be understanding, but IF the generator is still charging, that should not happen. There are other ways around that.

 

  Ben

[carbking]

I will disagree on holding the petal to the metal on a flooded engine with today's fuel.

 

Hot starting

 

Jon.

[MRJBUICK]

Matt you and i really don't know each other than maybe some forum posts but if i may comment

Sometimes over the years i have thought that my cars in their own way have been testing me to see if i am worthy of owning and driving them.

i know that when they get to much i close the garage door and concentrate on other parts of life for a while maybe an hour a day a week or more, go back refreshed and look at it differently, sleeping ALWAYS helps. having this as a business i am sure makes it more difficult for your own pleasure with your car.

please remember these cars never run perfect there wouldn't have been 4 gas stations on 1 intersection if they did.

Do not try to compare today's cars with our old cars there is way to much of a difference. our old cars you were lucky to get 100k with no major work now its just broken in at 100k

and 200-300k is not so unusual. enjoy the good times when they run right and smile and when they don't let them know you are better and smarter then they are.

As far as customers go, i have worked on a counter most of my whole life including now i love it most of the time and hate it at times.

it has never been as difficult as it is today dealing with customers, you can thank Amazon, Home Depot and the rest where you can return what you don't like, you don't even have to think it through before buying it. nobody listens when you talk they only hear what they want to hear. i know it sounds like i am generalizing there are some really great customers out there i would go way out of my way for. but it can be tough dealing with the buying public.

maybe with the customers you deal with you could try to feel them out and the good ones be really nice to and the tough ones be stern with not nasty just stand your ground if they want it they will pay for it if not don't let them waste your time.

as far as the inspectors they are getting paid to do a job, maybe it annoys you when you have explained the car correctly but they have to report back to the people paying them 

but if they give you a hard time for no reason give it right back, sometimes people have to be put in their place.

the Holidays are coming spend time with family as long as they don't drive you crazy, in the end they are whats important. if you are religious spend time there i have found that helps me!

hope this helps

 

 

[Lawrence Helfand]

23 hours ago, Ben Bruce aka First Born said:

 

 I may not be understanding, but IF the generator is still charging, that should not happen. There are other ways around that.

 

  Ben

Hi Ben, Switch works off vacuum so nothing to do with the generator and sometimes when I think I have stalled it is actually still turning at a ridiculously low rpm and I have hit the starter and crunch as it also thinks its stalled from sensing no vacuum.

[Ben Bruce aka First Born]

3 hours ago, Lawrence Helfand said:

Hi Ben, Switch works off vacuum so nothing to do with the generator and sometimes when I think I have stalled it is actually still turning at a ridiculously low rpm and I have hit the starter and crunch as it also thinks its stalled from sensing no vacuum.

 

 Hey Lawrence, I was referring to the ground from the generator to the starter relay. At least in 1950. There is a ground circuit from the field, I believe, that is closed, thereby grounding the starter relay UNTIL the generator begins ginning. Engine starts , generator starts charging, ground is broken and the starter relay is not grounded. Does yours not work that way?

 

  Ben

[Bloo]

In the mid 30s, there was actually a separate contact in the voltage regulator to perform that function.

 

[JohnD1956]

On 12/4/2019 at 5:56 PM, carbking said:

I will disagree on holding the petal to the metal on a flooded engine with today's fuel.

 

Hot starting

 

Jon.

 

What if the engine is cold?  I think that's the situation regarding this particular car.  Floods easily when cold. 

[carbking]

John - if I misunderstood, my apologies. I may have misread the comments. Flooding an engine when cold, to me, means either (probably) defective spark, or the carburetor is adjusted to rich. If the carb is the issue, then holding one's foot to the floor will activate the unloader circuit, but the choke will only be approximately 1/4 inch open, and the engine would flood worse. Just to prove this to myself, I would start the car, get it to normal temperature, and check the A/F ratios, especially at idle, adjusting if necessary. If the same thing happened again, I would check the firing voltages at the plugs.

 

Jon. 

[JohnD1956]

Thanks Jon. While it isn't my car thats the subject here I do wonder if this cold start flooding is because Matt is using two primary carbs? 

I have no first hand knowledge of the 1941 dual carb system but I thought I read that the original secondary carb had no choke system. And if I understnd it right the original design was for a progressive linkage to the 2nd carb. But Matt switched to 2 primary carbs with a direct linkage. This causes two chokes to come into play and a prime shot of gas from both carbs. Maybe it would help to adjust the 2nd carbs choke to a lean position so that it provides some air restriction but doesnt actually ever close

[carbking]

John - I don't think it is the use of two primary carbs that is the issue. I have been building and selling multiple carburetion for 40 years, and except for those building numbers matching showcars, ALWAYS use chokes on ALL of the carbs and solid linkage. Not just Buick, but all makes. My 1968 Ford F100 with a 435 HP 390 has two 625 CFM Carter AFB's running solid linkage, and manual chokes on both. Have done several Buicks over the years, and ALWAYS used two single carbs, as they were less expensive for the customer than fronts. They work well.

 

Jon

[Bloo]

What happens when you floor it to hit the unloader? It seems (without being there to see it), that if one carb doesn't have a choke, then that one carb would be wide open at WOT, and the other carb open whatever amount the choke unloader kicks it open. The choke unloader probably doesn't need to do much if there is another carb wide open. Add a choke to the other carb, and wouldn't you need both of the choke unloaders to be set a lot more aggressive?

 

Jon- What is the purpose of an unloader if not to clear out a cold engine that the owner accidentally flooded? That is the only thing I have ever used them for. It has worked for me getting screwed up cars driven into the shop more times than I can count. (I agree completely that  something was probably set too rich to flood it in the first place).

Edited December 7, 2019 by Bloo (see edit history)

[carbking]

Bloo - as you suggested, the purpose of the unloader circuit was to clear a flooded cold engine, BUT one with the choke working. In Matt's case, he is not activating the chokes by not using the footfeed. If he activated the chokes by pressing the footfeed, then the issue could possibly be worse.

 

Much depends on if the carbs ARE too rich, or if the ignition system is weak.

 

Jon.

Edited December 7, 2019 by carbking (see edit history)

[Matt Harwood]

Thanks for all the additional information, gentlemen. Right now, the car starts instantly and runs beautifully above about 45 degrees. Every time, hot or cold. But lately as I've been driving it daily in the cold, it has been problematic to start. I have found that if I prop open the choke on the rear carb, it starts right up and runs rough for about 20 seconds, then acts like nothing happened. I am not sure that I have the chokes configured properly, and that's something I plan to address. I have them backed way off (springs fairly loose) on the theory that since there are two of them, I don't need a lot of choke. Second, when it was running the factory sequential linkage and a floor starter, the factory starting position would have been front carb on the choke, rear carb wide open, no choke. So maybe I'm over-choking it and backing off the rear carb's choke even more would help. And after reading Jon's excellent information on his website about how the chokes work, including the little piston that is supposed to pull it open once the engine fires, I'm not convinced mine are working correctly. I'm still confused about the hows and whys of the spring mechanism AND that little vacuum piston--why have a gradual spring choke if the vacuum piston just pulls it wide open instantly? Which is more important to be functional? I have always had a slight vacuum hiss from the rear carb's choke area, so I'm not convinced the little piston is working correctly--I'll have to go in after it again.

 

So I guess my question is at this point: should I back off the rear carb's choke a lot or even disable it entirely? I assumed that in cold weather, more choke would be important, but this car seems to be the opposite--on warm days, it fires instantly with both chokes closed, but on cold days it refuses to run and floods instantly. Could the closed chokes be closed too far, creating too much vacuum which is in turn pulling too much fuel into the cylinders (AKA very rich)?

 

It seems counter-intuitive to me.

 

PS: Ignition is strong and all new and I get a big, fat blue spark, although repeated soakings during these flooded starts may have fouled plugs. I should pull them and have another look, too.

[valk]

It is distressing to hear one of our forum leaders is waivering.  Many of us rely on Matt and a few others to lift us up when stuff goes south.  I wish we could all meet at your place and collectively sort your car(s) out as payback for what you've given us. Hang in there, man, this too will pass...

 

I wonder if there are any "modern" carbs that bolt up and improve reliability?  It is a further step away from originality, but might be worth it if you drive a lot. 

Peter

[old-tank]

11 hours ago, carbking said:

I would check the firing voltages at the plugs

 

31 minutes ago, Matt Harwood said:

Ignition is strong and all new and I get a big, fat blue spark, although repeated soakings during these flooded starts may have fouled plugs. I should pull them and have another look, too

Check the voltage at the coil while cranking that big old cold engine with a cold 6v battery...

[JohnD1956]

2 hours ago, Matt Harwood said:

 

"When it was running the factory sequential linkage and a floor starter, the factory starting position would have been front carb on the choke, rear carb wide open, no choke. "

"Could the closed chokes be closed too far, creating too much vacuum which is in turn pulling too much fuel into the cylinders (AKA very rich)?"

"I have them backed way off (springs fairly loose) on the theory that since there are two of them, I don't need a lot of choke."

"I'm still confused about the hows and whys of the spring mechanism AND that little vacuum piston--why have a gradual spring choke if the vacuum piston just pulls it wide open instantly? Which is more important to be functional?"

"I assumed that in cold weather, more choke would be important, but this car seems to be the opposite--on warm days, it fires instantly with both chokes closed, but on cold days it refuses to run and floods instantly."

"So I guess my question is at this point: should I back off the rear carb's choke a lot or even disable it entirely?"

 

 

Matt,  I took the liberty of changing the order of some sentences from your previous post for this response:

 

"When it was running the factory sequential linkage and a floor starter, the factory starting position would have been front carb on the choke, rear carb wide open, no choke. "

This is what made me think disabling the rear carb's choke would be an advantage.  But Jon said he consistently applied two front carbs with their chokes and they worked.  

 

"Could the closed chokes be closed too far, creating too much vacuum which is in turn pulling too much fuel into the cylinders (AKA very rich)?"

For purposes of clarity, when the choke is applied,  the vacuum created within the engine will be forced to pull more fuel through the carb (s).  In your case it used to pull the fuel from one carb.  With the change to two primary carbs, it will now pull fuel from two carbs,  and in my opinion, resulting in too much raw gas in the intake system.  AKA, very rich.

 

"I have them backed way off (springs fairly loose) on the theory that since there are two of them, I don't need a lot of choke."

I believe this application for that theory is flawed.  You may not need more choke than was originally determined (choke on the primary carb only)  but you will need some choke once you have this all dialed in appropriately.  Even in the summer.

 

"I'm still confused about the hows and whys of the spring mechanism AND that little vacuum piston--why have a gradual spring choke if the vacuum piston just pulls it wide open instantly? Which is more important to be functional?"

That spring is thermostatically controlled.  When it is cold it will contract and that's what puts the pressure on the linkage so that when you step on the accelerator the choke should snap closed.  As the spring warms up it expands and releases the pressure on the linkage.  After the spring is sufficiently heated up, operating the accelerator will not close the choke.  The vacuum piston is there to force the choke to open once the cold engine is started.  It does take a few minutes of run time to warm the thermostatic spring enough to take that pressure off the linkage.  And if the vacuum piston was not part of the system, then, when cold,  the thermostatic spring would continually try to close the choke, thus flooding the engine. 

 

"I assumed that in cold weather, more choke would be important, but this car seems to be the opposite--on warm days, it fires instantly with both chokes closed, but on cold days it refuses to run and floods instantly."

I am not sure the concept of "more choke" is applicable.   Choke adjustment is generally described as lean or rich.  But I believe the engine in any car starts with the same amount of fuel to air ratio, and ambient temps are not a major consideration in the adjustment.  In fact, there appears to be an inverse relationship to adjusting the thermostatic spring considering the ambient temps.  Considering that the spring contracts when it is cold, it makes sense to think that it would contract more at 10* than at 45* .   And if the engine needs a certain air to fuel ratio to start and run,  a colder thermostatic spring would be putting tension on the linkage for a longer period as it warms up and expands enough to release the tension on the linkage.  Thus, you might need a leaner choke setting in extreme cold weather than when it is warmer.    When your car starts instantly on warm days it may be because the thermostatic springs are already further expanded and thereby releasing tension on the choke linkage earlier. In addition, if you suspect a problem with the little piston the rear carb it could be that the front choke opens enough to get air into the engine while the rear choke is closed and tending to flood the engine , thus your period of rough engine operation till that rear choke can open enough to stop flooding. 

 

"So I guess my question is at this point: should I back off the rear carb's choke a lot or even disable it entirely?"

That is worth a try to me.  It would be closer to what was originally designed.  Plus it would mean less time trying to coordinate the two chokes.  I would disable the rear choke by loosening the thermostatic spring to the lean side all the way.  Then adjust the front choke per the manual.  Or I would adjust the front thermostatic spring by feel.  With the engine cold, adjust the spring so that accelerator operation results in the choke butterfly closing completely.  And then an extra index mark on the cover.  That little extra is to keep the butterfly closed when the engine is first cranking over, before there is engine vacuum at the little piston to pull the choke off.  Otherwise the choke butterfly may be pulled open during cold cranking thus negating the choke benefits.   But that is just an initial adjustment.  You may have to close that rear choke partially which would be determined by how quickly the engine starts.   You ultimately need the chokes fully open when the engine is warmed up.  And they also must open partially ( which is what the little piston does) even when cold, to let the engine draw air to mix with the fuel.  

 

 

 

 

 

 

 

 

[Bloo]

4 hours ago, Matt Harwood said:

I'm still confused about the hows and whys of the spring mechanism AND that little vacuum piston--why have a gradual spring choke if the vacuum piston just pulls it wide open instantly? Which is more important to be functional?

 

On most cars, the spring sets the start position (and the fast idle), and the piston pulls the choke to the run position, not all the way open.

 

Carter DID make something that pulls the choke all the way open on start, my 36 Pontiac does that. I am not sure how that even works, but it runs good. That setup is NOT normal....

 

I'll bet by 41, the piston works like normal more modern cars, and just pulls the choke to a good run position. That would be closer to open than you would expect! Then the choke opens slowly the rest of the way as the car warms up.

 

If it were me, I would want both chokes doing the same thing on a car with a synchronized linkage like yours. If it floods on start, set the thermostatic coils looser. When it starts, both should snap to the same place, because the little pistons take care of that. There is probably an adjustment for the piston position vs choke position, usually called "choke pull off".

[Matt Harwood]

1 hour ago, JohnD1956 said:

Matt,  I took the liberty of changing the order of some sentences from your previous post for this response:

 

"When it was running the factory sequential linkage and a floor starter, the factory starting position would have been front carb on the choke, rear carb wide open, no choke. "

This is what made me think disabling the rear carb's choke would be an advantage.  But Jon said he consistently applied two front carbs with their chokes and they worked.  

 

"Could the closed chokes be closed too far, creating too much vacuum which is in turn pulling too much fuel into the cylinders (AKA very rich)?"

For purposes of clarity, when the choke is applied,  the vacuum created within the engine will be forced to pull more fuel through the carb (s).  In your case it used to pull the fuel from one carb.  With the change to two primary carbs, it will now pull fuel from two carbs,  and in my opinion, resulting in too much raw gas in the intake system.  AKA, very rich.

 

"I have them backed way off (springs fairly loose) on the theory that since there are two of them, I don't need a lot of choke."

I believe this application for that theory is flawed.  You may not need more choke than was originally determined (choke on the primary carb only)  but you will need some choke once you have this all dialed in appropriately.  Even in the summer.

 

"I'm still confused about the hows and whys of the spring mechanism AND that little vacuum piston--why have a gradual spring choke if the vacuum piston just pulls it wide open instantly? Which is more important to be functional?"

That spring is thermostatically controlled.  When it is cold it will contract and that's what puts the pressure on the linkage so that when you step on the accelerator the choke should snap closed.  As the spring warms up it expands and releases the pressure on the linkage.  After the spring is sufficiently heated up, operating the accelerator will not close the choke.  The vacuum piston is there to force the choke to open once the cold engine is started.  It does take a few minutes of run time to warm the thermostatic spring enough to take that pressure off the linkage.  And if the vacuum piston was not part of the system, then, when cold,  the thermostatic spring would continually try to close the choke, thus flooding the engine. 

 

"I assumed that in cold weather, more choke would be important, but this car seems to be the opposite--on warm days, it fires instantly with both chokes closed, but on cold days it refuses to run and floods instantly."

I am not sure the concept of "more choke" is applicable.   Choke adjustment is generally described as lean or rich.  But I believe the engine in any car starts with the same amount of fuel to air ratio, and ambient temps are not a major consideration in the adjustment.  In fact, there appears to be an inverse relationship to adjusting the thermostatic spring considering the ambient temps.  Considering that the spring contracts when it is cold, it makes sense to think that it would contract more at 10* than at 45* .   And if the engine needs a certain air to fuel ratio to start and run,  a colder thermostatic spring would be putting tension on the linkage for a longer period as it warms up and expands enough to release the tension on the linkage.  Thus, you might need a leaner choke setting in extreme cold weather than when it is warmer.    When your car starts instantly on warm days it may be because the thermostatic springs are already further expanded and thereby releasing tension on the choke linkage earlier. In addition, if you suspect a problem with the little piston the rear carb it could be that the front choke opens enough to get air into the engine while the rear choke is closed and tending to flood the engine , thus your period of rough engine operation till that rear choke can open enough to stop flooding. 

 

"So I guess my question is at this point: should I back off the rear carb's choke a lot or even disable it entirely?"

That is worth a try to me.  It would be closer to what was originally designed.  Plus it would mean less time trying to coordinate the two chokes.  I would disable the rear choke by loosening the thermostatic spring to the lean side all the way.  Then adjust the front choke per the manual.  Or I would adjust the front thermostatic spring by feel.  With the engine cold, adjust the spring so that accelerator operation results in the choke butterfly closing completely.  And then an extra index mark on the cover.  That little extra is to keep the butterfly closed when the engine is first cranking over, before there is engine vacuum at the little piston to pull the choke off.  Otherwise the choke butterfly may be pulled open during cold cranking thus negating the choke benefits.   But that is just an initial adjustment.  You may have to close that rear choke partially which would be determined by how quickly the engine starts.   You ultimately need the chokes fully open when the engine is warmed up.  And they also must open partially ( which is what the little piston does) even when cold, to let the engine draw air to mix with the fuel.  

 

 

Wow, thank you, John! That is EXTREMELY helpful. I may go fiddle with it tomorrow (Sunday) and see what happens. I have to admit that even after all these years, the science of carburetors is still a bit of a mystery to me. Fuel injection? No problemo. But this is like black magic sometimes and I get things right more by accident and trial and error than by procedure. This is an extremely helpful guide. Thank you!

[Lawrence Helfand]

As I have been running a matched carb parallel linkage for three years now using both 60 series Strombergs and smaller series 528s Carters I have experienced none of the issues Matt has encountered with cold starting. I did not find that flooding was ever a problem even with the larger Strombergs. I did shorten the accelerator pump adjustable linkage to reduce the volume of fuel . When I first switched over I did not hook up the rear choke thinking I would have enough just off the front. The result was lean popping and flame belch in the rear carb. Sync hing  up the chokes was really easy and only required a couple of adjustments. Like Jon said multiple matched carbs is not a problem any more then a single carb is when properly adjusted. This discussion has been incredibly informative so thanks for some enlightenment by expert members. Good luck Matt!

[carbking]

Disconnecting the choke on the rear carburetor will violate the "Law of Unintended Consequences"

 

WHY?

 

When running with the original progressive linkage, the throttle on the rear carburetor is closed at start-up, forcing all A/F mixture to be supplied by  the front carburetor.

 

When running with solid linkage, the throttle on the rear carburetor is open at start-up, thereby causing a severe imbalance of the A/F mixture density to the cylinders fed by the rear carb, thus creating the condition experienced by Lawrence in the post above this one.

 

Matt - how far out do you have the idle mixture control screws on both carbs? My GUESS would be somewhere around 1/2 turn would be about right.

 

At this point in time, why not start the adjustment procedure over. Pick a day when the ambient (or the temperature in your garage) is in the window of 65~70 degrees F., disconnect the linkage connecting the two carbs, one by one adjust the chokes by first working the throttle on each carb to wide open and then release. Open the throttle approximately 1/2 way and HOLD. Now loosen the screws holding the retaining clamps, and rotate the choke cap gently in each direction, looking for the direction that allows the choke butterfly to fall open. Now, gently rotate the choke cap in the opposite direction until the choke butterfly just touches closed with zero tension. Once both chokes have been adjusted, reconnect the two carburetors. Start the engine. Run the engine at a fast idle until the engine is totally at operating temperature. Turn one of the throttle positioner screws clockwise to give an idle of maybe 1000 RPM. Rotate each mixture control screw clockwise until lightly seated, then counterclockwise 1/2 turn. Which one is done in sequence is unimportant. Once all four have been adjusted to 1/2 turn, rotate the throttle positioner screw you used to set the fast idle counterclockwise SLOWLY, blipping the throttle each 1/8 turn to try to get your target idle RPM. Some further adjustment of the mixture control screws may be necessary, but shouldn't be much.

 

Now, the next time you go to start the engine cold: remove the air cleaner, and verify both chokes should be wide open. If not, we have an adjustment issue somewhere. If they are, GENTLY push the throttle wide open and release (take about 4 seconds to push the throttle open). Verify both chokes should completely close. Now, with the transmission in neutral and one tire blocked, open the drivers door window, stand outside the car, and start the engine! (no foot on the footfeed). It should start, and immediately go to a fast idle. You may need to adjust the fast idle to your target RPM.

 

The above procedure is assuming that you have previously synchronized the throttle operation of the two carburetors. If not, then that should be done as well.

 

Jon.

[Matt Harwood]

On 12/8/2019 at 10:06 AM, carbking said:

Disconnecting the choke on the rear carburetor will violate the "Law of Unintended Consequences"

 

WHY?

 

When running with the original progressive linkage, the throttle on the rear carburetor is closed at start-up, forcing all A/F mixture to be supplied by  the front carburetor.

 

When running with solid linkage, the throttle on the rear carburetor is open at start-up, thereby causing a severe imbalance of the A/F mixture density to the cylinders fed by the rear carb, thus creating the condition experienced by Lawrence in the post above this one.

 

Matt - how far out do you have the idle mixture control screws on both carbs? My GUESS would be somewhere around 1/2 turn would be about right.

 

At this point in time, why not start the adjustment procedure over. Pick a day when the ambient (or the temperature in your garage) is in the window of 65~70 degrees F., disconnect the linkage connecting the two carbs, one by one adjust the chokes by first working the throttle on each carb to wide open and then release. Open the throttle approximately 1/2 way and HOLD. Now loosen the screws holding the retaining clamps, and rotate the choke cap gently in each direction, looking for the direction that allows the choke butterfly to fall open. Now, gently rotate the choke cap in the opposite direction until the choke butterfly just touches closed with zero tension. Once both chokes have been adjusted, reconnect the two carburetors. Start the engine. Run the engine at a fast idle until the engine is totally at operating temperature. Turn one of the throttle positioner screws clockwise to give an idle of maybe 1000 RPM. Rotate each mixture control screw clockwise until lightly seated, then counterclockwise 1/2 turn. Which one is done in sequence is unimportant. Once all four have been adjusted to 1/2 turn, rotate the throttle positioner screw you used to set the fast idle counterclockwise SLOWLY, blipping the throttle each 1/8 turn to try to get your target idle RPM. Some further adjustment of the mixture control screws may be necessary, but shouldn't be much.

 

Now, the next time you go to start the engine cold: remove the air cleaner, and verify both chokes should be wide open. If not, we have an adjustment issue somewhere. If they are, GENTLY push the throttle wide open and release (take about 4 seconds to push the throttle open). Verify both chokes should completely close. Now, with the transmission in neutral and one tire blocked, open the drivers door window, stand outside the car, and start the engine! (no foot on the footfeed). It should start, and immediately go to a fast idle. You may need to adjust the fast idle to your target RPM.

 

The above procedure is assuming that you have previously synchronized the throttle operation of the two carburetors. If not, then that should be done as well.

 

Jon.

 

Thank you, Jon. I'm going to spend some time on it one night this week. It's still pretty cool so hopefully I can get the shop up to a reasonable temperature for tuning. I also have a training manual here somewhere with pretty detailed instructions for tuning the carburetors and I seem to recall it said something about setting the choke so a 3/32" drill bit could fit between the blade and the carburetor throat--I'll see if I can find it before I tear into anything.

 

My hunch is that even though I still set up the chokes to put very little spring pressure on the choke blade, I may have to back it off even more given how cold it is. That shouldn't affect warm weather operation, either other than the chokes might open a little sooner.

 

Thanks for all the advice. I'll report back once I get some time to really play with it. You guys rock!

[Lawrence Helfand]

46 minutes ago, Matt Harwood said:

 

Thank you, Jon. I'm going to spend some time on it one night this week. It's still pretty cool so hopefully I can get the shop up to a reasonable temperature for tuning. I also have a training manual here somewhere with pretty detailed instructions for tuning the carburetors and I seem to recall it said something about setting the choke so a 3/32" drill bit could fit between the blade and the carburetor throat--I'll see if I can find it before I tear into anything.

 

My hunch is that even though I still set up the chokes to put very little spring pressure on the choke blade, I may have to back it off even more given how cold it is. That shouldn't affect warm weather operation, either other than the chokes might open a little sooner.

 

Thanks for all the advice. I'll report back once I get some time to really play with it. You guys rock!

 Hi Matt, I will tell you that I tried the 3/32 drill bit setting and could not make it work at all as it requires a very light and ultimately inaccurate setup as it never could maintain this position. Also the NOS carbs in the box with from the factory did not employ this setting.  Just saying I found it to be totally useless. The factory  set chokes were lightly closed all the way and from there I left the front as is and just tweeked the rear to match. Mostly an adjustment to compensate for the slight lag from the slower heating of the coil due to jury rigged heat tube which was just a few moments behind in actuation.  

[Matt Harwood]

Although I've been focused on the Lincoln lately--my goal is to take it to the 100th anniversary in Hickory Corners in August--our reliable #1 go-to tour car is the Limited. My project list on this car is pretty extensive, so it's time to get busy. I haven't had time to adjust the carbs but since time is slipping away for big projects I wanted to tackle those jobs that would require that I take it off the road for some time. Item #1 on my list is the cooling system. That's not necessarily because anything is wrong--the thing obviously runs ice cold--but the water pump is noisy (it's by far the loudest sound on the car whenever it's running--listen carefully to either of the exhaust system videos I posted earlier) and the radiator has a seeping seam. Neither issue is fatal, but there will surely be a time when we're miles from home and one or the other gives up. Now's the time to address them. I have a brand new water pump on the shelf and a great radiator shop in Ellet Radiator who can take care of the leaking seam. Since they're re-coring a radiator for a 1937 Ford panel truck, I'll just take the Buick's radiator when I pick that one up. 

 

The Limited has never had overheating issues (not even close even under the most demanding circumstances), but as you'll see below that fact seems kind of miraculous. Given what I found in the cooling system, it should not have been as efficient as it is. I'm actually a little concerned that I'm going to disrupt the system and it won't run cool anymore. I am merely going to have the radiator shop clean out the radiator, fix the leaky seam, and paint it, but there will be no new core. I can't see how cleaning out the water jackets in the block will have a negative effect on cooling, but it wouldn't be the first time doing something that should make a car better has actually made it worse. I'm more than a little nervous about upsetting whatever perfect balance of factors I had going on before starting this project. This is exactly the kind of thing that I screw up when I tackle a project.

 

Anyway, I started by recruiting my son, Riley, to help me remove the hood--it's easy on these cars, just pull both latches and lift. It's a little bulky but we stashed it in a safe spot so it won't get hurt while we're working on the car. I think it looks kind of badass with the hood off.

 

Removing the hood is easy and gives great access to the engine bay.
Note to self: reverse the horns so they're aimed properly.

 

Next step was draining the radiator. Someone had thoughtfully
added a drain hose on my radiator.

 

While it's draining, remove the upper radiator cover.
Seven bolts and it just lifts off.

 

  
Once it's drained, remove both radiator hoses. Frankly, I was a little surprised by the amount
of rust in the system. This car runs ice cold--like 165 degrees on 95 degree days--and never
had any sings of cooling system distress, but it's pretty messy in there. I'm glad I'm servicing it.

 

The spring was still in the lower hose--very important! I ordered new
molded hoses, but just in case the replacement hose doesn't have
a spring, I removed this one and threw it in a bucket of Evapo-Rust
so I can re-use it if needed.

 

  
Remove four bolts that hold the fan and pulley on the water pump. It's a bit of a 
geometry problem to maneuver them out but it can be done with the radiator in place.

 

    

If you're not replacing the thermostat you can leave it alone, but since I'm going to be running
my Evapo-Rust pump to clean out the water jackets, it needs to be removed. My
thermostat housing was held in place with a gasket and a whole lot of orange sealant.
Note that the thermostat was a 160-degree unit, which I'll be re-using since the car runs so cool.
I made a new temporary gasket and reinstalled the thermostat housing so I can run the Evapo-
Rust through the block, which appears to be sorely needed.

 

Remove the 10 bolts that hold the radiator to the core support and
carefully remove the radiator by lifting straight up. I put a piece of
cardboard over the radiator face to avoid damaging it on the water
pump nose. Note that it my engine was apparently painted after the
water pump and pulley were installed. That's kind of strange but
it was rebuilt about 5000 miles before I bought it; I'm not sure
why they chose to do it that way...

 

Radiator is in decent shape, but as you saw in earlier photos, there's
a lot of gunk in there and the seam between the top tank and the core
seeps a little after a long drive. How was it still so effective?!?

 

This hose connecting the water pump to the bypass valve is important
and should be replaced when the water pump is serviced. I have correct
hose clamps to use for reassembly.

 

You also have to drain the block and the Buick straight-8 has a small
drain plug on the passenger's side near the back of the block. So I
removed it... and nothing came out. Huh? Just a trickle of greasy black

liquid. Very strange--is it clogged with rust? We'll see what happens
when the Evapo-Rust has cleaned everything out. I might even add a 
fitting here to help it drain while the Evapo-Rust is running through it.

 

I threw the fan (standing up) and the pulley (far right) in the sandblast
cabinet and prepped them for powdercoat. I have a batch of parts
for the Lincoln so I'll take these as well. The fan will be gloss black but
the pulley is supposed to be cad plated, so I'll powdercoat it satin silver
to simulate that look. 

 

  
I installed the fittings I made to connect my water jacket cleaning system to the block.
Once I'm done cleaning out the Lincoln's water jackets, I'll move the system over to the 
Buick and run heated Evapo-Rust through it for a week or two. It should be spotless in
there by the time I'm done. 

 

If you haven't been watching my Lincoln thread, here's a brief video showing my water jacket de-rusting system. I've been running heated Evapo-Rust through the Lincoln's water jackets for about three weeks now and I think it's about done. I'll use the system to cycle some detergent through the Lincoln to remove the slime that Evapo-Rust leaves, then I'll move it to the Buick, starting with some water to just flush it out as much as possible. I like to run it backwards with the Evapo-Rust going in at the thermostat housing and exiting through the water pump inlet. Doing it that way tends to dislodge more debris as it goes against the normal flow direction. I'm very curious to see what happens, particularly at that rear drain plug. If you haven't been following my Lincoln thread, here's my water jacket cleaning system in action:

 

 

Edited February 9, 2020 by Matt Harwood (see edit history)

[Fr. Buick]

I would use that drain plug hole on the back of the block for some strong blasts of air and water, before the Evaporust.    Maybe remove a freeze plug back there to at least let the worst crud escape, as back there is where the crud will be the worst.  Run a filter for a while when it is back together to catch anything else that got "disturbed..." and still floating through the system

 

Love to watch your projects, BTW!

[Matt Harwood]

This project isn't to cure overheating, it's just replacing the water pump, which is noisy, and the radiator, which has a seam leak. I figured that as long as it's apart, I should clean the water jackets with some Evapo-Rust. I wanted to use the circulation system I devised for the Lincoln's V12 to clean out the water jackets and it initially looked like simply using the inlet and outlet hoses would be a simple solution. The bypass housing screwed all that up.

 

Anyway, my first thought was to simply remove the little stub of radiator hose between the bypass valve and the water pump inlet and just cover them with a sheet of rubber and a hose clamp, like home-made lids on jars of jelly. That would seal them up well enough to run the circulation system at 4 PSI or so.

 

I thought if I could remove this hose, I could seal the two flanges
with some rubber and hose clamps...

 

  

...but no. That little brass post means it would not be easy to seal after all.

 

Unfortunately, the brass post that holds the bypass valve in place extends into the water pump neck, so that wouldn't work. I removed the bypass housing and disassembled the valve, which is in good condition, but I couldn't get the brass post out. Bah. So I'll have to think of something else. I need to seal both openings temporarily to circulate the Evapo-Rust through the block and head, but I don't feel like making custom fittings. They're not nice and round like on the Lincoln so making my own special fittings will be a major job. 

 

Who would have thought the Buick would be the difficult one?

 

I have two ideas for how to solve this issue; I'll try the cheap and easy one tomorrow.

[38Buick 80C]

Matt,

What I did with the radiator bypass is as follows.

 

As we all know when the spring gets week the water bypasses the radiator. If you take the spring and washer out that you are in full bypass mode as well so not good either. I took a spare piece of stainless fuel or brake line and cut it to the desired length and placed it around the post and put the spring and the washer and pin back in place. This makes the washer/spring combo un-collapsible and thus all water MUST go through the radiator (aside from the as Buick engineered it amount that goes around the washer a bit). Aside from a longer warm up there are no ill effects to the Buick and ensures despite the spring weakening you still get all coolant through the radiator.  Stainless will also not rust. simple cheap and easy to do.

 

as for use during evaporust I suppose you could do the opposite and place a sealing washer at the bottom and simply build up washers or a cut line slightly short as described above and then another washer at the top to lock it all down and get a good hard seal.

[Matt Harwood]

That's a good idea, Brian. I think I'll do that when I put it back together. I've seen a lot of advice to just cut out the brass post and use a freeze plug with a hole drilled in it, but since my bypass valve was working properly I don't really want to cut it apart. Maybe not critical to the overall function of the cooling system, but it seems a shame to permanently maim a part that still works. 

 

My cheap and easy solution to temporarily blocking off the bypass was rubber plugs. I drilled a hole in one so it would slide over the post and seal the bypass valve housing. Then I drilled a partial hole in the one going into the water pump so that the post would fit in it and help hold it in place. Unfortunately, I couldn't find quite the right size plugs, particularly on the byapss side, which has a stepped opening. So even with the holes drilled, I couldn't compress them enough to reinstall the bypass on the block. So that's a no-go.

 

Meh. Plugs almost worked but I couldn't get them to compress
enough to reinstall the bypass housing. Never mind.

Plan B is to machine some flange adapters and simply bolt them to the block in place of the water pump and bypass valve and hook up the hoses directly. That's probably better anyway. I have some 1/2-inch Delrin laying around somewhere, which is easy to drill and tap and stiff enough to seal to the block with a gasket. That'll be Saturday's project, I guess. I'm also going to thread a barbed fitting into the drain plug in the side of the block and run a separate tube of pressurized Evapo-Rust directly to it and hopefully clean it out from both sides. As I mentioned, my car runs nice and cool, so I'm not too worried, but this is my only chance to get it cleaned out so I may as well do it right.

 

I simply removed the water pump and I'll make
custom fittings to bolt to the block and head.

 

The inside of the block doesn't look too bad, actually.

[JohnD1956]

2 hours ago, Matt Harwood said:

That's a good idea, Brian. I think I'll do that when I put it back together. I've seen a lot of advice to just cut out the brass post and use a freeze plug with a hole drilled in it, but since my bypass valve was working properly I don't really want to cut it apart. Maybe not critical to the overall function of the cooling system, but it seems a shame to permanently maim a part that still works. 

 

My cheap and easy solution to temporarily blocking off the bypass was rubber plugs. I drilled a hole in one so it would slide over the post and seal the bypass valve housing. Then I drilled a partial hole in the one going into the water pump so that the post would fit in it and help hold it in place. Unfortunately, I couldn't find quite the right size plugs, particularly on the byapss side, which has a stepped opening. So even with the holes drilled, I couldn't compress them enough to reinstall the bypass on the block. So that's a no-go.

 

Meh. Plugs almost worked but I couldn't get them to compress
enough to reinstall the bypass housing. Never mind.

Plan B is to machine some flange adapters and simply bolt them to the block in place of the water pump and bypass valve and hook up the hoses directly. That's probably better anyway. I have some 1/2-inch Delrin laying around somewhere, which is easy to drill and tap and stiff enough to seal to the block with a gasket. That'll be Saturday's project, I guess. I'm also going to thread a barbed fitting into the drain plug in the side of the block and run a separate tube of pressurized Evapo-Rust directly to it and hopefully clean it out from both sides. As I mentioned, my car runs nice and cool, so I'm not too worried, but this is my only chance to get it cleaned out so I may as well do it right.

 

I simply removed the water pump and I'll make
custom fittings to bolt to the block and head.

 

The inside of the block doesn't look too bad, actually.

That hole for the  water pump passage kinda looks like it is the same size as a thermostat housing for a 3800 v6.  Maybe it would pay to make a template of the hole and then visit a NAPA To see if they have any of the cast housings in stock.  

[Matt Harwood]

I made custom fittings today to connect my Evapo-Rust pump to the Buick straight-8. I had some leftover Delrin plastic laying around, which is easy to work with. It cuts easily, drills easily, takes threads well enough, and is strong enough to handle bolts torqued down. Perfect for this kind of application. I used the water pump gasket and the base of the bypass valve housing to make shapes that I cut roughly to shape. I left them a little oversized to make them durable enough to handle some torque at the mounting bolts. Then I drilled 3/8-inch holes for the bolts and a 23/32 hole in the center, which I tapped for 1/2-NPT threads for a hose fitting. The water pump uses a round hole in the block, but the bypass valve on the head uses a rectangular hole, so I made that one a little oblong. Then I hooked it all up and turned it on.

 

  
I used the water pump gasket to make a shape on a sheet of 1/2-inch thick Delrin.

 

  
Then I drilled the holes and tapped the center hole for 1/2-NPT pipe threads. It's easier to drill and
tap the material while it's a bigger chunk, so I saved cutting it out for last.

 

  

Then I cut it out and installed the brass 1/2-NPT to 3/4 hose fitting.

 

I made some gaskets to match and used some 3/8-16 header bolts
to secure the two adapters to the block after cleaning the mounting surfaces. 

 

From there it was easy to hook up the hoses from the pump (blue) and
drain (red) to start circulating Evapo-Rust through the water jackets.
For now, I'm circulating it backwards, in at the top and out at the bottom.

 

A heater in the bucket of Evapo-Rust keeps it warm as it circulates,
which greatly increases its effectiveness.

 

I'm going to get some fittings tomorrow and connect a second hose to the drain plug on the side of the block so that pressurized Evapo-Rust will start feeding in there and hopefully removing whatever is blocking it. I hit it with a shot of air and nothing happened, so we'll see if we can determine what's going on there.

 

I hope the Evapo-Rust treatment is effective (my results on the Lincoln blocks were inconclusive). I'm seeing small clues that things are amiss in the cooling system, but the damned thing runs ice cold all the time, no matter what. There's the drain plug on the block not draining, which I fear is clogged with rust. And as I was looking around under the hood, I saw that the high-temperature coating on my new headers was turning to powder on the rear cylinders--could it really be THAT hot? I'll pull the plugs and have a look, but is it possible that the rear two or three cylinders have been running super hot while coolant was 165 degrees and the engine ran perfectly all the time? I honestly don't know, but I need to find out so I can trust the car again.

 

The high-temperature ceramic coating on my new headers is burning 
off and turning to dust. Product defect or is cylinder #8 running super hot?

Edited February 16, 2020 by Matt Harwood (see edit history)

[valk]

Maybe one of these gyzmos would help: Raytech Minitemp. I think I got this years ago as a gag present for Christmas but it has proven very helpful, particularly for my air-cooled British bikes. 

 

[valk]

This is a better pic showing what it does...

 

[EmTee]

12 hours ago, Matt Harwood said:

is it possible that the rear two or three cylinders have been running super hot while coolant was 165 degrees and the engine ran perfectly all the time?

 

Is there a fitting somewhere near those rear cylinders where you could temporarily install a second (aftermarket) temperature sender and gauge?  Then you could see what's happening as you drive.

Edited February 16, 2020 by EmTee (see edit history)

[Matt Harwood]

4 hours ago, EmTee said:

 

Is there a fitting somewhere near those rear cylinders where you could temporarily install a second (aftermarket) temperature sender and gauge?  Then you could see what's happening as you drive.

 

The back of the block by the firewall has the port for the factory temperature gauge, which has never worked on my car. I initially thought it was because the aftermarket gauge's sending unit took its place, but no, it's just broken. I have an NOS temperature gauge to install this is the time to do that. I'm not sure what is in the port for the sending unit, probably the original gauge's bulb--the rest of the unit is just hanging there. I don't know how accurate the factory gauge is, but maybe before I install it I'll do some testing with some boiling water to at least get a frame of reference. 

 

The more I think about it, I don't think anything is wrong temperature-wise. There's just no way that thing could run that cool and that well in such hot weather and still be cooking a few cylinders. If that header tube was coming undone due to heat, why aren't the ports on the cylinder head burned? The engine paint is far less tolerant of high temperatures than the ceramic coating. I think they just screwed up the coating and it's coming undone. I'll either have to paint it on the car or remove it (oh God, I don't want to do that) and send it to Jet-Hot to be re-coated with the good stuff. 

 

I'll post updates on everything as it progresses...

[Ben Bruce aka First Born]

Matt, you say the temp bulb goes into the block?  I have never owned a 320.  The 248/263 is in the head. And many of those have been broken needlessly.  Many folks do not realize the bolt  hole for the rocker stand directly above is a through hole. A longer bolt than factory is some times used and contacts the bulb, sorta locking it in place.

 

  Ben

[Matt Harwood]

Went up to the hardware store and picked up some fittings to connect a second line to that blocked drain plug in the block and let the Evapo-Rust work on it from both sides. Unfortunately--and like usual--the car had other ideas. Turns out that the little plug in the block is indeed 1/4 NPT (pipe thread) but it's not tapered like a pipe thread. So it's the same but different. Why? Why do they do it that way? Every little thing unique. So I screwed in a 1/4 NPT fitting and felt it snug up, which I thought was good, but turns out it actually started stripping threads. I left it in there since it seems to be holding pressure, but I'll have to figure something out later once I need to seal it up. I'll probably have to drill and tap it for a 3/8 NPT plug. Won't that be delightful down there in the engine bay?

 

Installed a fitting and some tubing to feed Evapo-Rust to the 

drain hole in the block. Note the air bubble...

 

It certainly appears that the drain hole is well and truly blocked. You can see the air bubble in the tubing above, demonstrating that there's zero movement of the liquid into the block. I loosened the fitting slightly to bleed off most of the air, but that's as much as I could get out without having liquid spraying all over the place. I do seem to recall that when I first bought the car, I had a local mechanic back-flush the block for me and he told that the drain plug was blocked; in his opinion it was a casting flaw and maybe it was never fully drilled out. I guess we'll find out. Maybe a pinhole will open up and the fluid will start to flow into the block. Or maybe I'll need to drill it out for a 3/8 plug anyway.

 

I also spoke with the folks at Sanderson Headers, who did the ceramic coating on my header. While they're perfectly willing to re-coat the headers--which I appreciate--they are also of the opinion that the air/fuel mixture is way out of whack and exhaust gas temperatures (EGTs) are so high that it's burning off a coating rated to 1900 degrees (they did note that the bolt adjacent to cylinder #8 is discolored, which would suggest a lot of heat). I don't rightly know how an engine with 7.5:1 compression and running under 3000 RPM could possibly generate that much heat, but OK, I'll look into it. I'll pull the plugs first and see what's going on, particularly in the rear cylinders. They also suggested using a 4-gas analyzer to tune it, and fortunately I have a friend who has one, so I'll do some more tuning once it's reassembled. Bigger jets in the carbs? Smaller? Just adjust the idle screws? 

 

I just can't understand how a car could run this well, this cool, and for this long if it had cylinders burning so hot that it destroyed a high-temperature ceramic coating. 

 

And, of course, the hits kept coming. The radiator shop called and told me that every time they fixed a seam on my radiator, another one would blow. The radiator is shot. Again, how the hell did this car run so cool and so effortlessly for so long with a junk radiator, super lean fuel mixture, bum water pump, and clogged water jackets? How?!?

 

Anyway, I told them to re-core the radiator. They have a modern 5-row core with straight fins that's slightly cheaper than a duplicate of the original core (it'll only be $1100), while an original-style core would probably be closer to what I paid for the Lincoln's radiator ($1800). Even though it should be better than before, I have a genuine concern that more changes will upset whatever perfect balance I had going on and it'll never run cool again. That's how things usually work for me--simple for everyone else, everyone else gets results, but when I try everything goes sideways. A new radiator, new water pump, and clean water jackets should mean it will run cool.

 

Anyone want to bet $10 that it runs worse than ever once I put it back together? I have zero faith in my abilities anymore. Bah.

[Bloo]

On many cars, heck almost every car I have pulled those plugs out of, the crap in the bottom of the block has plugged the hole and I have had to root around in there with a screwdriver or a piece of bailing wire to get things flowing. Once the flow starts the crud will break up much easier. Have you tried to pick away at it with anything? Was it just too solid?

 

As for the plug, I'll bet you will find it is tapered pipe thread, but the modern-era plugs are just rubbish, maybe a little too big or a little too tapered. Straight pipe threads do exist, but generally require something other than the threads to seal, and rarely if ever show up on American cars. Whether it's tapered or not, I'll bet once you get it derusted you will have another thread or two available, and it will probably work with the old plugs. If you can get them in mechanically solid, but worry about leaks, Indian Head will take care of that. I would use Indian Head on those even with perfect threads. Good luck and keep us posted.