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thermoquad choke
#729799
06/20/10 08:31 PM
06/20/10 08:31 PM
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Joined: Jan 2003
Posts: 4,599
St. John's Newfoundland
440newport
OP
master
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OP
master
Joined: Jan 2003
Posts: 4,599
St. John's Newfoundland
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I swapped a t-quad onto my 400 and now I need some kind of a choke. You can get the spring/electric style choke still but it's supposed to use a "control switch" to turn it on and off. Do you need this and can you still get it? Also napa seems to have an electric choke conversion, but I've never heard of them for a thermoquad, will this work? Not cheap though. Link to NAPA site
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Re: thermoquad choke
[Re: 440newport]
#729804
06/20/10 09:56 PM
06/20/10 09:56 PM
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Joined: Oct 2008
Posts: 765
Shoreline, Washington
72roadrunnergtx
super stock
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super stock
Joined: Oct 2008
Posts: 765
Shoreline, Washington
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"Interesting, so you find the stock style ones don't last? I did some more digging around on the napa site and found what seems to be a newer version of it. Think this would be any better?" The NAPA link isn't working for me, takes to a "enter a zip code-store location search page". There was a design change around late seventies/early eighties to a smaller round metal case version. Only slightly more reliable, when I was wrenching at a dealer back then, replacing these became part of scheduled tune-ups. Cap, rotor, plugs, air filter, and choke controller. 
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Re: thermoquad choke
[Re: 72roadrunnergtx]
#729808
06/21/10 04:17 PM
06/21/10 04:17 PM
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Joined: Aug 2007
Posts: 6,120
Valencia, España
NachoRT74
master
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master
Joined: Aug 2007
Posts: 6,120
Valencia, España
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1st... the electric choke control is an asistant to heat sooner the bimetallic coil and get iddle faster when warming from cold
2nd... being an assistant IS NOT MANDATORY to hook it up, just will take longer to get iddle, because bimetallic coil will still be heated up by the manifold heat source
3rd... the electric choke control were released on those years in two presentations. Single stage to /6 and 318 cars. IS the unit on first pic. Provides one voltage lever to heat the coil until engine bay gets hot. Then double stage, what is basically same unit, but with an external ballast resistor attached ( same resistor like the round unit shown ), to change the voltage level and heats the coil in two diff stages as far engine bay gets hot, sensed by the ballast.
On these years the source to the electric choke control was spliced from the blue wire running to alt field what provides power in RUN
on later years this control took the power from same RUN source but JUST when the engine is running, The only way to get this was an oil sender with a positive switch to send the power JUST when oil gets the sender, what it means engine is running. That keeps safe the choke is being feeded with key accidentally in RUN but engine not running. This oil sender has 3 prongs. Oil function what is ground as any earlier sender, and the positive input FROM RUN and positive output to choke
With a Charger born in Chrysler assembly plant in Valencia, Venezuela
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Re: thermoquad choke
[Re: NachoRT74]
#729809
06/22/10 10:49 AM
06/22/10 10:49 AM
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Joined: Jun 2006
Posts: 3,075
Eastern Ohio
mopowergtx
master
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master
Joined: Jun 2006
Posts: 3,075
Eastern Ohio
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Quote:
1st... the electric choke control is an asistant to heat sooner the bimetallic coil and get iddle faster when warming from cold
2nd... being an assistant IS NOT MANDATORY to hook it up, just will take longer to get iddle, because bimetallic coil will still be heated up by the manifold heat source
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Re: thermoquad choke
[Re: mopowergtx]
#729810
06/22/10 12:12 PM
06/22/10 12:12 PM
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Joined: Oct 2008
Posts: 765
Shoreline, Washington
72roadrunnergtx
super stock
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super stock
Joined: Oct 2008
Posts: 765
Shoreline, Washington
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Quote:
Quote:
1st... the electric choke control is an asistant to heat sooner the bimetallic coil and get iddle faster when warming from cold
2nd... being an assistant IS NOT MANDATORY to hook it up, just will take longer to get iddle, because bimetallic coil will still be heated up by the manifold heat source
Only partially correct, Keep in mind the heat riser valve on the passenger exhaust manifold was eliminated around 73’ reducing the total amount of heat at the choke well during warm-up. Using the heated divorced choke in the original factory configuration (factory carb calibration, factory intake manifold, and functioning heat crossover system) the additional heat provided by the heater was necessary to maintain the correct choke spring tension in relation to the operating temperature/ fuel mixture requirements. A prolonged fast idle also equates to a prolonged choke function, leading to an unnecessary over rich condition after engine reaches operating temp for a period of time. The controllers usually failed due to the burned contacts within, creating high resistance, stopping the full electrical flow to the heater, prolonging choke function. In the applications using the by-pass resistor, which allows for a reduced current flow to the heater (less heat) after the controller contacts have opened, additional heat was required to maintain the spring in a relaxed state at full operating temp.
Everything being original and functional, a choke heat controller is needed for the correct function of the choke system. When these cars were new, a functioning controller was MANDITORY, to meet exhaust emission standards of the day. Not to mention meeting customer fuel consumption and drivability expectations at the time.
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Re: thermoquad choke
[Re: 72roadrunnergtx]
#729811
06/22/10 01:14 PM
06/22/10 01:14 PM
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Joined: Jun 2006
Posts: 3,075
Eastern Ohio
mopowergtx
master
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master
Joined: Jun 2006
Posts: 3,075
Eastern Ohio
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Quote:
Quote:
Quote:
1st... the electric choke control is an asistant to heat sooner the bimetallic coil and get iddle faster when warming from cold
2nd... being an assistant IS NOT MANDATORY to hook it up, just will take longer to get iddle, because bimetallic coil will still be heated up by the manifold heat source
Only partially correct, Keep in mind the heat riser valve on the passenger exhaust manifold was eliminated around 73’ reducing the total amount of heat at the choke well during warm-up. Using the heated divorced choke in the original factory configuration (factory carb calibration, factory intake manifold, and functioning heat crossover system) the additional heat provided by the heater was necessary to maintain the correct choke spring tension in relation to the operating temperature/ fuel mixture requirements. A prolonged fast idle also equates to a prolonged choke function, leading to an unnecessary over rich condition after engine reaches operating temp for a period of time. The controllers usually failed due to the burned contacts within, creating high resistance, stopping the full electrical flow to the heater, prolonging choke function. In the applications using the by-pass resistor, which allows for a reduced current flow to the heater (less heat) after the controller contacts have opened, additional heat was required to maintain the spring in a relaxed state at full operating temp.
Everything being original and functional, a choke heat controller is needed for the correct function of the choke system. When these cars were new, a functioning controller was MANDITORY, to meet exhaust emission standards of the day. Not to mention meeting customer fuel consumption and drivability expectations at the time.
Funny.  You sure about that heat riser valve being eliminated in the passenger exhaust manifold after '73. I've never looked but I sure hear one flapping around on my bone stock 78 Lebaron 318 when its warming up. And all the heads had heat crossovers (LA, B, RB) that I have ever had. And every stock iron manifold I've ever took off had a heat crossover in it. My take on the electrical assist is to quicken the choke pull off so to apease the EPA goverment goons. Because like you said the quicker you get the choke off the quicker you quit spilling Polar Bear killing, ozone depleting high content carbon monoxide fumes into the air.
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Re: thermoquad choke
[Re: mopowergtx]
#729814
06/22/10 03:34 PM
06/22/10 03:34 PM
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Joined: Oct 2008
Posts: 765
Shoreline, Washington
72roadrunnergtx
super stock
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super stock
Joined: Oct 2008
Posts: 765
Shoreline, Washington
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Quote:
Funny. You sure about that heat riser valve being eliminated in the passenger exhaust manifold after '73. I've never looked but I sure hear one flapping around on my bone stock 78 Lebaron 318 when its warming up. And all the heads had heat crossovers (LA, B, RB) that I have ever had. And every stock iron manifold I've ever took off had a heat crossover in it. My take on the electrical assist is to quicken the choke pull off so to apease the EPA goverment goons. Because like you said the quicker you get the choke off the quicker you quit spilling Polar Bear killing, ozone depleting high content carbon monoxide fumes into the air.
I guess you can never too specific here, I never meant to say that all heat riser valves went away on all applications in 73’. The OP was referring to big block application and many 73’ and later BB manifolds do not have a heat riser valve making the correct choke/heat timing more dependant on the heated spring and controller being operational. EPA mandated or not, again WHEN THESE CARS WERE NEW, all calibrations were set to include this system functioning as designed. Testing and correcting any malfunctions with the heated choke system was included in all factory published guidelines of the day as part of scheduled tune-up maintenance for these cars.
Quote:
Also I have read in FSM, a 1976 one I believe, about those electrical assist systems where they had a hot assist side and a cold assist side. Nut shell if this assist was above a certain temp it would heat up the choke faster IE already hot engine compartment or hot day. And it also had how to adjust the ohms I believe on them to regulate the speed at which they opened them. I guess it kinda sounds like your ballast deal your refering too.
Yes there is a thermal component to the correct operation of the controller; it was designed to time out quicker under heat soak conditions. The original design of the controller has factory sealed off adjustments to the bi-metal contact arm to set this temp/timing mechanically during their assembly. These adjustments were never meant to be serviced in the field however. Both the original and later button style controller were designed to be bolted under an intake manifold bolt specifically to absorb engine heat directly.
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Re: thermoquad choke
[Re: mopowergtx]
#729816
06/22/10 11:32 PM
06/22/10 11:32 PM
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Joined: Oct 2008
Posts: 765
Shoreline, Washington
72roadrunnergtx
super stock
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super stock
Joined: Oct 2008
Posts: 765
Shoreline, Washington
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Go ahead piss in my Wheaties, see if I care  I simply responded to the OP's inquiry regarding what it was and if it's still available with a link to an older discussion containing detailed info. Followed then by more specific answers to questions about the choke control in general. I went back though this entire thread, I don't see anywhere were I advised that his car wouldn't RUN if he didn't use a choke control. So let me see if I understand this, a mid 70's BB without a heat riser valve will get just much heat, just as quickly, at its open choke well as a 69"BB would with a functional heat riser valve at its closed choke well? Sure about that? Tell me why, with applications using a controller with the by-pass resistor, would partial choke spring heat be required throughout the full run cycle if the factory thought there was sufficient crossover heat to insure that the spring would be relaxed completely? You doubt the existence of mid 70's heat riserless exhaust manifolds?  Never fails, whenever I get involved with detailed discussions about why things were done a certain way back in the day, there's always the debunkers. I.e. the thread linked above in response to inquires about the six pack choke mod, " Why do you even need to have a choke, just wire it open" . Sometimes I wonder why I even bother.
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Re: thermoquad choke
[Re: 72roadrunnergtx]
#729817
06/23/10 06:08 AM
06/23/10 06:08 AM
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Joined: Jun 2006
Posts: 3,075
Eastern Ohio
mopowergtx
master
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master
Joined: Jun 2006
Posts: 3,075
Eastern Ohio
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Quote:
Sure about that? Tell me why, with applications using a controller with the by-pass resistor, would partial choke spring heat be required throughout the full run cycle if the factory thought there was sufficient crossover heat to insure that the spring would be relaxed completely?
 
Are you saying you need the electric assist to keep the choke "open" once the engine is up to operating tempature? I dont have it in front of me now to scan and post it, but the 76 FSM says the V-8 two stage assist has no electric going to the choke above 130F.  So yeah I guess Im saying the choke will come all the way open and stay open throughout the run cycle without electric going to it. There will be enough heat sink from the engine to fully open any factory intake mounted choke system even one without a properly working heat crossover system. And the lack of heat riser in that BB manifold is interesting. But I can tell you I have one in my 78 318. I'll look and see hopefully today or tomorrow if theres one in my 77 'Doba 400 Thermoquad non-HP.  I do notice that manifold you pictured looks to be of a HP style. Could that have something to do with it not having one?
 
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Re: thermoquad choke
[Re: mopowergtx]
#729818
06/23/10 01:22 PM
06/23/10 01:22 PM
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Joined: Oct 2008
Posts: 765
Shoreline, Washington
72roadrunnergtx
super stock
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super stock
Joined: Oct 2008
Posts: 765
Shoreline, Washington
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Quote:
Are you saying you need the electric assist to keep the choke "open" once the engine is up to operating tempature?
No, in my experience, stock configuration, cast iron intake/heads, open cross-overs, heat riser working correctly or not, although choke timing was off, I’ve never seen a choke spring that wouldn’t eventually relax completely with an inop/missing choke heater or controller. With that said, the later button type controllers having the by-pass resistor, the resistor serves only one purpose and that is to allow for partial current flow to the heating element regardless of the switching taking place in the controller. At full voltage, I’ve measured about 1.6 amps of current drawn by the heater, thru the resistor this current draw dropped to around 600-700ma, again this reduced heating was present throughout the entire run cycle by factory design. Could very well be simply some kind of fail safe in the event the controller switching fails (and they did) there would still be some heat function.
I can tell you from more current first hand experience that in a NON-STOCK BB configuration with blocked cross-overs in aluminum heads, aluminum intake, correct spring tension for correct cold start/run/drivablity, the choke spring will not relax completely at normal operating temperature without this reduced extra electrical heat. Hence, the reason for the “heated six-pack choke spring” mod.
I do have another non-hp manifold stashed somewhere from a 74’ TQ equipped 440 that doesn’t have a heat riser valve as well. I spent the first year of my dealer wrenching stint back then, working the “lube rack” at a rather large Chrysler/Plymouth dealer. I’ve spayed countless cans of Mopar heat riser solvent on countless heat risers. I recall taking note then, when heat risers started to disappear from some of these cars.
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