1949 Electric Sisson Choke

[Branded]

Im planning to rewire the Wayfarer and convert it to 12 volts. What have you all used to drop the voltage to the electric Sisson choke. I know I need to use a rhunt on the fuel gauge.

[Branded]

No one has keep their electric choke when converting to 12 volts ?

[Plymouthy Adams]

just how long do you plan on grinding the starter?

[Branded]

just how long do you plan on grinding the starter?

Long enough to start the engine

Ive done 6 to 12 volt conversions on other cars over the years using to 6 volt starter and never had an issue

Edited August 19, 2015 by Branded

[Plymouthy Adams]

did you not know that the sissons is only engaged for as long as the starter is turning..and that you must lock the linkage with a depression of the gas pedal if you intend to use the choke?  the book is fairly clear on the operation including the owners manual for HOW TO START...

 

if you concerned,,,use OHMS law and do the math...keep in mind that the proper value resistor at the correct wattage inline and piror to the component will drop the volt load in 1/2....this value is determined by the component in use...again...time for the meter and the math..

Edited August 19, 2015 by Plymouthy Adams

[Branded]

I wasnt aware how the choke actually operated or how to set the choke. Havent purchased a owners manual or servic emanual yet. Not much on the math part on electricity. Was hoping i could just use a voltage drop inline to the sission choke.

[Plymouthy Adams]

you can use a voltage drop...but again..to be effective in reaching the very voltage drop you want..ohms law is the method to ascertain that value..or you can just guess.....there is not a true one size fit all in application...

[mlozier76]

Here is a pretty good definition of Ohm's Law.http://diyaudioprojects.com/Technical/Ohms-Law/  When I learned it in aviation they used E where V was for electrons or potential energy, which made a little better acronym:  P=iE, E=Ri, R=E/i, AND P=i^2(SQUARED) X R.  Remember P= Watts (Power), E or V = Volts,  i = Amps (Current flow), and R = Resistance (ohms).  I simply used lower case I because it looks like a 1 otherwise.

Edited August 19, 2015 by mlozier76

[desoto1939]

The electric sisson choke is triggered by the electrical wire that runs from the starter. An electric current moves the arm that moves the control rod that closes the choke buttefly. The choke is sitting on the top of the manifold ans has a bimeatalic plate that as the manifold gets hotter the plate then releases. the the choke and it comes back to the normal open position

The sisson automatic choke will always be triggered when you start the car. even in the summer but the bimetallic strip on the bottom of the choke is what really control how much the choke will operate.

I do have the instruction sheet for these chokes and can sell you the choke manual. I have this choke on my 39 Desoto

Sometime you will find on the Ebay 12volt version of the sisson choke, yes 12v I have seen these several times

Rich Hartung

Desoto1939@aol.com

Edited August 19, 2015 by desoto1939

[jeffsunzeri]

Im planning to rewire the Wayfarer and convert it to 12 volts. What have you all used to drop the voltage to the electric Sisson choke. I know I need to use a rhunt on the fuel gauge.

Don't do it. There is no good reason to convert to 12 volts, especially if you are bad at the "math part on electricity" and plan on introducing rhunts into the system.

[Branded]

Don't do it. There is no good reason to convert to 12 volts, especially if you are bad at the "math part on electricity" and plan on introducing rhunts into the system.

Well don't shoot me but I'm a hot rodder at heart and have wired my fair share of cars in the past 40 years. Never had to do the math do wire a car yet The only thing I'm looking at adding a rhunts to is the gas gauge. The reason I chose to convert to 12 volt is for modern electrical items such as electronic ignition, and radio.

[DJ194950]

I run my 50 Ply. on 12v. to the choke, No resistor, just a heavy gauge wire from starter to choke.

 

Has been that way for two years now, no problem. Have a spare though just in case.

 

Sisson made Many styles of electric chokes over the years- 30's and up to the 70's. No longer in production. Google sisson choke-12 volt and some possible place to purchase come up from NOS stock even other brands 12v.

 

Chrysler used many different models over the years. All where 6v. I believe. Some where mounted behind the carb. on the intake manifold and later went to the front side of carb.

 

Onan motors and Wisconsin brand used them for years and later year models where 12 v. But are they correct configuration?

[ACJCF2]

My car was converted when I bought. It has the Sisson choke and it works as advertised.

[Frank Elder]

RUNTZ.

[suntennis]

A place on internet called fifthaveinternetgarage.com with phone of 758-632-3450 sells a 12 volt conversion package and should be able to help with a resister if needed for the choke.

[jeffsunzeri]

The reason I chose to convert to 12 volt is for modern electrical items such as electronic ignition, and radio.

 

Neither ignition nor radio changes are good reasons to change system voltage and incur the cost of molesting your vehicle with a new coil, generator/alternator, all bulbs, regulator/rectifier, flasher, blower motor(s), wiper motor, etc.

 

Electronic ignitions are readily available in 6 volt at the same cost as 12 volt, and all the 12 volt accessories you could want can be run from a converter, starting at around $60 and available all over.

 

Of course, you can do whatever you want but I just feel it's a shame to needlessly molest something that has lasted this long as a messenger from the past, and is likely to survive both you and me and can continue to be a touchstone for others to come.

[Plymouthy Adams]

what works for one person may not be the cup of tea to another...if change you want..then change you should go for...when you pass GO, collect your $200.00 and accelerate forth like no tomorrow...because...they may not be a tomorrow..with the rate I move forward with upgrades, a tired old messenger from the past will never even glimpse my taillights

[meadowbrook]

There must be something wrong with my vehicle's Sisson, when I got the car, I noticed the wire from the starter to the Sisson was not connected, I connected it and it promptly melted when cranking the engine. So the electrical part must be shorted out. But the thermostatic part still works in that the choke plate is closed when cold and fully open when hot.

 

My car starts easily when cold and ok if I use the proper pedal technique when hot (crank for about 5 sec and then slowly add throttle).

 

So am I correct in stating that the current from the starter shuts the choke when cranking (no matter what the temperature of the engine) to make it easier to start a hot engine?

[Plymouthy Adams]

do a test with an ohm meter to determine if the choke coils is shorted internally or to ground of the housing itself..

[DonaldSmith]

Maybe a screw is too long and is shorting the wire to ground.  It has happened before. 

[Plymouthy Adams]

Maybe a screw is too long and is shorting the wire to ground.  It has happened before. 

very valid and sobering thought..do not overlook this possibility

[_shel_ny]

 

So am I correct in stating that the current from the starter shuts the choke when cranking (no matter what the temperature of the engine) to make it easier to start a hot engine?

 

Energizing the sisson choke always pulls the rod  connected to the choke, but how far it closes is determined by the bi-metallic spring in the base of the sisson.  I believe fully closed or there abouts with a cold engine, and progressively less as the spring is affected by rising manifold temperatures.

 

 

 

EDIT: spelling

Edited August 20, 2015 by shel_ny

[_shel_ny]

There must be something wrong with my vehicle's Sisson, when I got the car, I noticed the wire from the starter to the Sisson was not connected, I connected it and it promptly melted when cranking the engine. So the electrical part must be shorted out. But the thermostatic part still works in that the choke plate is closed when cold and fully open when hot.

 

 

Checking the sisson choke with a meter can be misleading. The choke is just an electro magnet. A coil of wire wrapped around a core, so it has a very low resistance.  My cheesy HF digital meters don't even zero out on ohms so I can;t even check one with them

[Plymouthy Adams]

I will not start the HF bashing..lol  BUT..even my high dollar Fluke digitals are lacking...but yet..they can still be tested...an analog meter is best and a high end unit is often needed then...I have referenced the book and have not found any given OHM range value of the coil else I would have posted it for the man to go by.....I know they will be hovering way low in value..

 

for the record..just one of many sites that may help you if you inquisitive enough to get down and dirty

 

http://www.robotroom.com/Measuring-Low-Resistances.html

Edited August 20, 2015 by Plymouthy Adams

[_shel_ny]

My sperry meter has only a 1K reading for resistance, so it is not much help to read a sisson either.

 

Direct application (quick flash) of 6 volts has been the best way for me to check a sisson choke.

 

Best done with the choke isolated from the starter. The wire from the choke to starter can conduct enough voltage to engage the starter. Been there, done that