Stumble at Throttle Tip In - Dual Carbs

[timkingsbury]

On January-06-17 at 6:08 PM, Bmartin said:

I am having trouble solving an issue on my new engine,maybe 100 miles on it.  I have a 230 with a milled head, split manifolds with true duals, and an Edmunds dual carb intake with two factory B&B's.

I have a stumble at throttle tip-in and have to feather throttle to get it to take off smoothly.  I've tried the middle position on the accelerator pump as well as the winter (richest) setting.  Currently at the richest setting.  Only real difference I noticed was needing more return spring to keep the throttle from hanging.

Seems to improve some with higher engine temps, but I have trouble getting it fully heat soaked since there are no hood or fenders right now.  The weather is also cool.  Temp is sitting at 160-180 typically.

Ignition:  I'm running a twelve volt system with resistor wires, Autolite 295's gapped at .025, and twelve volt coil with internal resistor.  Plugs have been reading lean to good.

Timing:  I set piston 6 at TDC, the rotor pointed to cylinder #1, and timing indicator was right at the center mark on the pulley.  I have tried 0 advance, about 4 degrees advance, and also about 12 degrees advance - amazingly I never detected any pinging.

Gears:  I'm a little under geared right now with 3.55's in the rear and 29" tall tires.  So it bogs a little at take off.  Still stumbles when moving if the revs drop low enough <~1200 rpm.  Factory 3 speed with O/D but thats locked out right now.

 

I'm looking for some ideas to try and especially any first hand experience.  For those with a similar setup, do you have any stumble or does it roll away from a stop as smooth as stock?  Do you have to feather the throttle at all?  Right now I'm wondering if I have to go with Tom Langdons two barrel carbs to get rid of this.  Any help is appreciated.

 

 

 

I apologize as I thought I had directly posted an answer to you original post and I don't see it posted so I must have done something on the multiple response.  I  also see you have a plan to balance the linkage.  That certainly wont hurt, but if I doubt it will solve your problem.   Moving to two barrel carbs, will cost more and be less effective that rebuilding your current carbs, making sure they are exact twins for all of the components.   While there are some things like plug gap I would change, you seem to have racked you brain and tried almost everything else.  If you wish drop me a PM and I would be happy to try and help.  I do not have an Edmunds dual intake on a 230. I do on two other motors, and have multiple vehicles with dual carbs, some from the factory and some added later, and 2 with triple carb setups.   Ive encountered what you are describing many times. Once everything else was checked, including making sure there is no leaky gasket situation, if unresolved it was always time to get into carbs and get them built or rebuilt.   I use the term built because even a pair of carbs with for example mis-matched centers are by their very nature unbalanced.
 

22 hours ago, knuckleharley said:

I pretty much agree with one stipulation. The only way you are going to benefit from using 2 brl carbs is if you have a 2 brl intake and the engine is built to be used at higher RPM's than normal street driving.

I also happen to think that the ideal street setup for a inline 6 flathead is a 3 x 1 intake with 3 small 1 brl carbs,but since I haven't ran a flat 6 on the street or anywhere else with either a 2 x 1 or a 3 x 1 setup yet,this remains a theory.

When I do end up running it,it will be with a 3 X 1 Tattersfield or Edmunds intake (I have both) using either 1904 Ford/Holley carbs or B&B's,a higher compression aluminum head,a 3/4 cam,and split exhaust on a 251 Chrysler engine,so what I discover probably won't be very useful for guys running stock 218 or 230 engines with dual carbs.

I have seen some 2 x 2 intakes for 218-230 Mopars though,and wondered how they worked on street cars. I can see how they would work good on race cars,but would think a 2 x 1 intake and carbs would work better on a stock engine.

Well the dual carbs is not just for higher rpm. Chrysler put dual carbs on lower reving, higher torque engines from the factory.  Drop over to my blog "Keeping up with the AoK boys" and you can see pictures of that and all kinds of intakes.

You are correct that 3 single carbs with dual exhaust is the ideal street setup.  It provides the best fuel distribution into the flathead 6 engine, and ironically I was asked to do a blog entry on the topic.  The key for multiple carbs is to have the correct sized carbs.  If you have a factory 201 ci 25 1/2" engine, rebuilt completely stock and put 3 smaller cfm carbs on it. you will get better fuel mileage, better throttle response and better performance and that is not just theory. We have a customer with one of our AoK triple intakes who has this exact situation on a 201 engine.  Perhaps he will feel comfortable enough to chime in here.

Now you did tweek my interest, you have a 3 x 1 Tattersfield ?    I would love to see a picture.   We have a 2 x1 which is the coolest intake ever. Wish it performed as good as it looked but  still cool.  Would love to see a triple as that I have never seen.
 

22 hours ago, knuckleharley said:

I've often wondered how a 6 port inline engine would work with 6 individual manifolds using small 1 brl carbs like used on some motorcycles or small furrin cars.

Why not? I used to run a  SU carb off of a 4 cylinder Volvo on my bored and stroked cammed up knucklehead Harley,and that thing was a LOT faster than most modern buzz-bike owners would believe.

 

It actually doesn't work as well as you might think. It worked slightly better with the modification of the block to provide individual access to each cylinder and then providing a balance tube where multiple carbs were mounted.   My father and grandfather worked on the concept on multiple engines and I believe at some point I can come up with one of the later experimental blocks.   In any case they could never get it to perform as well as a similarly built engine with an Edmunds triple carb intake.

 

16 hours ago, sser2 said:

I will, although I cannot promise quick progress. I have full-time job and many other commitments.

As to advantages of multi-carb intake on a flat six engine, I fully agree, but on one condition: these advantages are only realized at wide open throttle and high engine speed, when you are trying to squeeze out maximum power. At partial throttle and low engine speed, a single small-bore carb beats a bigger carb, or multiple carbs, in response and economy.

As an everyday driver, I use partial throttle most of the time, and full throttle high rpm only occasionally. Accordingly. I am much more concerned with partial throttle performance.

My goal is 30 mpg at steady 60 mph highway driving, not winning races.

I do admire  your spunk and despite how it may come across this isn't intent to start a fight.   Open throttle is not how it actually works and attached at the bottom, documentation and a picture of an actual dual carb and dual exhaust manifold, right from the Chrysler Engine Plant in Windsor Ontario for the 1952 Model year trucks. Somewhere I am sure I can come up with the HP and Torque curve, but for sure its advantage was definitely not only a wide open throttle. Far from it actually and it had zero to do with racing.

As for a 30 mpg goal, that is a lofty goal although, not impossible.   Quite a deviation from this thread, but one I would be happy to chat about or point you in the direction of a few who have built lighter weight cars, with mopar overdrives, better rear end gear sets and have been in the upper 20s for miles per gallon. I  don't know if any have hit 30 mpg or better.
 

2 hours ago, MarkAubuchon said:

I have run dual carbs on my car since I put them on the road with the same set up as yours.  My sedan runs flawlessly my coupe does have a slight hesitation ( i rebuilt the carb myself).

check for any leaks on the carbs using starter fluid, reconfirm the linkage set up.  Who built the carbs? I do know that when George Asche builds them he makes sure they are the same casting/part numbers, float adjustment is huge and he does alter the jet sizes, also labeling #1 front & #2 rear . I also agree with the other tips, points, plug gap timing are important.  MY money is on the carbs not being built the same.  I'd also call george, send him the carbs and they will be ready for Spring.

 

For me -  Your the best answer on the thread!    Yes perhaps a biased point on my part, but I still think in the end you have the correct answer.

With that, I realize everytime I post, it has the potential to continue on and on, so I think MarkAubuchon and others have given the original poster information to solve his problem so for me, time to move on from the thread.

Thanks folks, if you want me pm me, drop me an email or visit me on the "keeping up with the AoK blog"!

Tim Kingsbury

fargopickupking@yahoo.com

Edited January 8, 2017 by timkingsbury

[knuckleharley]

 

 

58 minutes ago, timkingsbury said:

 

Well the dual carbs is not just for higher rpm. Chrysler put dual carbs on lower reving, higher torque engines from the factory.  Drop over to my blog "Keeping up with the AoK boys" and you can see pictures of that and all kinds of intakes.

Yes,but those were all small valve high-torque engines designed to produce maximum torque at modest RPM's in order to move heavy loads. As i am positive you know,the rules change when you bump up the lift and duration of the cam,add dual exhaust,and bigger valves with more compression.

 

Also,the dual carbs were both single barrel carbs. I THINK we were talking about dual 2 barrel carbs on a 23 inch Mopar engine,and I just honestly don't see how a street short block flat 6 Mopar can benefit from 2 2 brl carbs.

58 minutes ago, timkingsbury said:

You are correct that 3 single carbs with dual exhaust is the ideal street setup.  It provides the best fuel distribution into the flathead 6 engine, and ironically I was asked to do a blog entry on the topic.  The key for multiple carbs is to have the correct sized carbs.  If you have a factory 201 ci 25 1/2" engine, rebuilt completely stock and put 3 smaller cfm carbs on it. you will get better fuel mileage, better throttle response and better performance and that is not just theory. We have a customer with one of our AoK triple intakes who has this exact situation on a 201 engine.  Perhaps he will feel comfortable enough to chime in here.

Now you did tweek my interest, you have a 3 x 1 Tattersfield ?    I would love to see a picture.   We have a 2 x1 which is the coolest intake ever. Wish it performed as good as it looked but  still cool.  Would love to see a triple as that I have never seen.<<

I will take a photo when I go  out to the shop to feed the shop cats this afternoon,and post it on this thread. I just happened to handle it yesterday when I was out there,so this is the rare instance where I know exactly where something is this moment. The Tattersfield intake has plugs for water heat,but the 3x1 Edmunds intake I have for 25 inch Mopars doesn't. It's the only Edmunds intake I have ever seen that doesn't  have the water tubes,and seems to have been listed as a "racing intake". I live in eastern NC,so the water heat is no big deal for me either way. As long as I don't have the exhaust manifold bolted to the intake manifold,I'm happy.
 

It actually doesn't work as well as you might think. It worked slightly better with the modification of the block to provide individual access to each cylinder and then providing a balance tube where multiple carbs were mounted.   My father and grandfather worked on the concept on multiple engines and I believe at some point I can come up with one of the later experimental blocks.   In any case they could never get it to perform as well as a similarly built engine with an Edmunds triple carb intake.

I will take your word for it on the value of "small carb for each intake port" issue on Mopars. You have far more experience in this area than I do.

 

58 minutes ago, timkingsbury said:

I do admire  your spunk and despite how it may come across this isn't intent to start a fight.   Open throttle is not how it actually works and attached at the bottom, documentation and a picture of an actual dual carb and dual exhaust manifold, right from the Chrysler Engine Plant in Windsor Ontario for the 1952 Model year trucks. Somewhere I am sure I can come up with the HP and Torque curve, but for sure its advantage was definitely not only a wide open throttle. Far from it actually and it had zero to do with racing.

No,but once again it did have a lot to do with moving heavy loads with small engines. The thing is they were designed to be a part of an engineered package,not a bolt on system. The carbs,intake runners,ports,timing,etc,etc,etc were all part of a package to produce maximum torque at low RPM's.

As for a 30 mpg goal, that is a lofty goal although, not impossible.   Quite a deviation from this thread, but one I would be happy to chat about or point you in the direction of a few who have built lighter weight cars, with mopar overdrives, better rear end gear sets and have been in the upper 20s for miles per gallon. I  don't know if any have hit 30 mpg or better.

It ain't NEVER going to happen with a flat 6 Mopar in a stock passenger car or truck,though. They are too heavy and geared too low to get anywhere close to that kind of MPG at 60 MPH. As you say,add taller tires,taller gears,better induction and exhaust,and an overdrive trans,and it might be doable,but it ain't going to happen by just making intake changes.

 

[Bmartin]

For reference, this a fresh built engine, built by George Asche, carbs and all.  I worked on the balance and got them about 90%, still struggling with the linkage adjustment.  Still no change. 

[oldasdirt]

1 minute ago, Bmartin said:

For reference, this a fresh built engine, built by George Asche, carbs and all.  I worked on the balance and got them about 90%, still struggling with the linkage adjustment.  Still no change.

George Asche built this engine, carbs, linkage  and your having issues ?   What did he say when you called him about the issues ? 

[Bmartin]

He has not been all that helpful.  I'm in AZ and he is in PA so there is the trouble of working over the phone. 

[oldasdirt]

3 minutes ago, Bmartin said:

He has not been all that helpful.  I'm in AZ and he is in PA so there is the trouble of working over the phone.

There is no smarter flathead mopar alive. I cant imagine you can resolve more on this forum than talking directly with George Asche.

 

[50plymouth]

When George built carbs and linkage for me they were built and setup on the intake by him.   I literally bolted it on the engine, hooked up my linkage coming across the head to his linkage.  I fired it up and the engine never ran so smooth.  I didn't touch any of the carb adjustments.  When you build as many as he does I am sure its possible to have an issue once in a while. I am not saying this is case here, nor am I suggesting you have over adjusted one or both of the carbs. I am sure George will work to resolve your problem. I would suggest another call or talk Tim Kingsbury up on his offer.   George and Tim as the A and K or AoK racing and what George who is in his mid 80s doesn't have in computer skills Tim makes up for the partnership. There is 3 hours difference in time between you and them. I am sure if you reached out right now you could get either of them. That is my 2 cents on the topic.

[knuckleharley]

2 hours ago, timkingsbury said:

  Now you did tweek my interest, you have a 3 x 1 Tattersfield ?    I would love to see a picture.   We have a 2 x1 which is the coolest intake ever. Wish it performed as good as it looked but  still cool.  Would love to see a triple as that I have never seen.
 

Tim,I was wrong. My Tattersfield is a 2 x 1 intake. My 3 x 1 intakes are an Edmunds and a Nicson. Here is the Nicson I was "remembering" as being a Tattersfield. You can't see them in the photo,but it has female fittings for nipples for water heat. Right now they are plugged. I have no idea how rare this is or isn't,but I happened to spot it for sale right after I had sold something else and had some "extra" money in my pocket,so I bought it.

BTW,I have only seen a couple of these Nicson's,but they were all painted red. Were they red when they left the factory?

 

BTW,let me know if you ever run across a 3 x 1 Intake,a finned aluminum head,and a set of cast iron dual exhaust manifolds for a 226 flat 6 Ford passgenger car.

 

 

[55 Fargo]

5 minutes ago, knuckleharley said:

Tim,I was wrong. My Tattersfield is a 2 x 1 intake. My 3 x 1 intakes are an Edmunds and a Nicson. Here is the Nicson I was "remembering" as being a Tattersfield. You can't see them in the photo,but it has female fittings for nipples for water heat. Right now they are plugged. I have no idea how rare this is or isn't,but I happened to spot it for sale right after I had sold something else and had some "extra" money in my pocket,so I bought it.

BTW,I have only seen a couple of these Nicson's,but they were all painted red. Were they red when they left the factory?

 

BTW,let me know if you ever run across a 3 x 1 Intake,a finned aluminum head,and a set of cast iron dual exhaust manifolds for a 226 flat 6 Ford passgenger car.

 

 

Very kool knuck!

The Ford stuff, better chance on the HAMB possibly?

[knuckleharley]

Just now, Rockwood said:

Very kool knuck!

The Ford stuff, better chance on the HAMB possibly?

I check it almost daily. Not much was made for the inline flat 6 Fords. All the Ford boys had to have a V-8 cause 6's weren't "cool" even if they did have more power.

Thanks for the suggestion,though. I do have a 2 x 1 Edmunds for it,but would prefer a 3 x 1 intake with a matching head if possible.

There used to be two different companies that made the cast iron dual headers for the 226 Fords,but somebody must have ate all them because I am having no luck finding one. I do have an extra truck and extra passenger car exhaust manifold,but I really don't want to cut them up if I can avoid it.

[Bmartin]

When spraying fuel at the base of the carb around the spacer, do I need to worry about any secondary effects?  I noticed that the starter fluid has a cooling effect.  If the idle goes down, can I be sure that a vaccum leak is causing that?

[Bmartin]

On 1/7/2017 at 7:24 AM, suntennis said:

Since the problem is reduced with higher engine temperatures,  have you tried choking the carbs some to see if the problem is reduced?

I will say that the engine acts different, but not a cure.  Seems like less stumbling at tip in but goes quickly to choking at any more throttle.  Its not very consistent.

[DJ194950]

With engine running -Instead of spraying anything that is flammable  at the carb parts and bases etc., others have suggested used an opened (slightly open I assume)  but not lit propane touch. Propane is lighter than air so will rise and not collect or pool on engine parts which should be safer than some others way to check. Never had need to try it since I read about this method on this forum,  but if I needed to do that kind of checking I will certainly try it!

DJ

[Don Coatney]

With the engine running any thing flammable should make a noticeable difference in idle speed if there is a vacuum leak in the intake manifold or the base of the carburetor.   

[DJ194950]

While propane IS flammable obviously it is Not a liquid that can pool. There are other spray type cans with flammable gas/liquids that also work to do this check, OP was concerned about the flammability issue. Seemed to me the propane was the least likely to cause any issues due to it's lighter than air and rises than  many other types often used that  are heavier than air and tend to settle in low areas around motor. I have personally used these other types of flammable liquids/gases to test for leaks, but I can be very care free at times- -   but  this trait  has caused some regrets! 

DJ

[timkingsbury]

4 hours ago, Bmartin said:

When spraying fuel at the base of the carb around the spacer, do I need to worry about any secondary effects?  I noticed that the starter fluid has a cooling effect.  If the idle goes down, can I be sure that a vaccum leak is causing that?

I will send you a PM. Something is not adding up here.  If you can spray anything at the base of the carb and effect the idle, then whatever you are spraying is getting into the intake.  If you have a poorly sealed carb to the intake, you can have exactly what you are describing and then if you start making carb adjustments you just add to the issue without solving the root cause.

[timkingsbury]

5 hours ago, knuckleharley said:

Tim,I was wrong. My Tattersfield is a 2 x 1 intake. My 3 x 1 intakes are an Edmunds and a Nicson. Here is the Nicson I was "remembering" as being a Tattersfield. You can't see them in the photo,but it has female fittings for nipples for water heat. Right now they are plugged. I have no idea how rare this is or isn't,but I happened to spot it for sale right after I had sold something else and had some "extra" money in my pocket,so I bought it.

BTW,I have only seen a couple of these Nicson's,but they were all painted red. Were they red when they left the factory?

 

BTW,let me know if you ever run across a 3 x 1 Intake,a finned aluminum head,and a set of cast iron dual exhaust manifolds for a 226 flat 6 Ford passgenger car.

 

 

That is fine, as my Grandfather  Kingsbury would say -  if your not making mistakes your likely not doing much.  It learning from those mistakes that matters.  I have seen one of those Nicsons in my lifetime and didn't have a picture of it.  I didn't remember it having water heating and of course the Eddy Edmunds triple didn't.  Eddy did use water heating on a few different intakes but stopped using it on is last generation of intakes.  Unlike the direct exhaust heat to help warm up the intake quickly at start up, by the time the water is actually warm enough to make a difference, the engine is already warmed up.  In terms of color, all the dual intakes for Plymouth/dodge and Chrysler I have seen were red or had been blasted.

Id love to see a profile picture to see if its much like the Edmunds profile or if it has more of a gradual curve from carb to block. I will attach a picture of the Edmunds and the foam core internal piece used for our AoK triple.

 

Not all of the big block engine manifolds they made for the 331, 377 and 413 ci really big block engines were painted red but some certainly were.    I am saying that having a 413 that I know where never touched and a 377 I know were never touched and 1 is red and 1 is not.  They were both bought by a municipality and both came from the municipality to my family.

 

Beyond that..  I will drop you a PM.

[knuckleharley]

2 hours ago, timkingsbury said:

 

Id love to see a profile picture to see if its much like the Edmunds profile or if it has more of a gradual curve from carb to block. I will attach a picture of the Edmunds and the foam core internal piece used for our AoK triple.

 

 

Will do as soon as it warms up enough for me to get it out in the sun.

BTW,that one looks just like the 3x1 Edmunds I just bought.

Did Edmunds ever make these for the 23 inch engines? If not,did anyone else?

Edited January 9, 2017 by knuckleharley

[Dodgeb4ya]

Tim.... "Not all of the big block engine manifolds they made for the 331, 377 and 413 ci really big block engines were painted red but some certainly were.    I am saying that having a 413 that I know where never touched and a 377 I know were never touched and 1 is red and 1 is not.  They were both bought by a municipality and both came from the municipality to my family."

What are you saying ?.... meaning the red or not color of the 377/413 intake manifolds?... 

[timkingsbury]

1 hour ago, knuckleharley said:

Will do as soon as it warms up enough for me to get it out in the sun.

BTW,that one looks just like the 3x1 Edmunds I just bought.

Did Edmunds ever make these for the 23 inch engines? If not,did anyone else?

No Edmunds never made a triple for the 23 1/2" small blocks.  George Asche has made quite a few from stock intakes though. Here is a picture.

[timkingsbury]

1 hour ago, Dodgeb4ya said:

Tim.... "Not all of the big block engine manifolds they made for the 331, 377 and 413 ci really big block engines were painted red but some certainly were.    I am saying that having a 413 that I know where never touched and a 377 I know were never touched and 1 is red and 1 is not.  They were both bought by a municipality and both came from the municipality to my family."

What are you saying ?.... meaning the red or not color of the 377/413 intake manifolds?...

On anything other than the 331/377/413 engine series everyone I have ever seen came from the factory red.   On the super big blocks I have seen red ones and silver ones. I don't know if they dropped the red at some point.

[Dodgeb4ya]

The 1950-52 377's  and later 413's only came with factory built cast iron dual intake and exhaust manifolds painted only silver.

The inside and outside of the block and out side of the heads of course were painted Glyptol red enamel then painted silver on the exterior by the factory.

The only after market dual intakes I have ever seen for the big  Moly Block engines  is an "Ellis".intake......Raw aluminum color...

Marketed as a power up grade for the late 1946-50  281/306 and 331 engines with a single 1 BBL. intake manifold.

[busycoupe]

Propane is denser than air, and will"sink".  It may not be important when working on an engine that is exposed top and bottom, but you have to be very careful when using it on a boat.  Boats typically have outside lockers to store propane tanks to ensure that a leak won't fill up the hull and create an explosion hazard.

[DJ194950]

1 hour ago, busycoupe said:

Propane is denser than air, and will"sink".  It may not be important when working on an engine that is exposed top and bottom, but you have to be very careful when using it on a boat.  Boats typically have outside lockers to store propane tanks to ensure that a leak won't fill up the hull and create an explosion hazard.

I am Wrong again!

I do remember that on boats about the propane lockers and some had a vent that went outside that was lower than the locker if not the locker itself!

Some larger world traveler sail boats were equipped with compressed natural gas(cng) instead of propane which Is lighter than air Which was available almost worldwide!

Sorry OP about going so OT!

DJ

[Plymouthy Adams]

LNG...this brings back a blast from the past.....I had a part in the making of these babies in a former life...you have no clue of the enormity of these huge gas balls till you are standing inside one....getting it from the assembly hall to the barge for its journey north was a massive exercise unto itself..good ole days for sure..

http://marinelinked.com/vessels/aquarius-tankers-general-dynamics-210579