Choke Thermostat - 56/57

Rusty_S85

Rusty_S85

Member
Ive been looking around the last couple of days for a reasonably priced NOS choke thermostat by the part number B6A-9848-C. All I find is too expensive for me to justify the cost for a driver.

Wanted to ask if anyone around here knows what is a reasonable price for this item? Maybe I am expecting it to be cheaper.
 
If the car is a 'driver' does the part have to be NOS?
Is the carb a Holley 4000 (teapot) ? They weren't used in '57 except for the E & F code engines.
Single 4bbl in '55 & '56. If you really want NOS they haven't been made in almost 50 yrs.
The *it has to be 100% original* car builders & collectors increase the price for the remaining supply.
I just looked in two '55/'57 T-bird resto catalogs, replacement choke thermostats are about $30.
.
 
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dmsfrr said:
If the car is a 'driver' does the part have to be NOS?
Is the carb a Holley 4000 (teapot) ? They weren't used in '57 except for the E & F code engines.
Single 4bbl in '55 & '56. If you really want NOS they haven't been made in almost 50 yrs.
The *it has to be 100% original* car builders & collectors increase the price for the remaining supply.
I just looked in two '55/'57 T-bird resto catalogs, replacement choke thermostats are about $30.
.
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My thing is some replacement parts from the restoration companies are hit and miss. The choke thermostat I have now doesn't have the locator mark on it so I don't even know where index is at so I cant even tell where the thermostat should be set at initially.

Now aftermarket replacements I don't know if they will have the mark or not. NOS I would like to have just for the fact that I know it will have it and be correct for my application if there is a difference in the spring rate for the choke thermostat.

Needing a NOS its not needed but I would like to have it though.

The carb is a Holley 4000. Ive found a few different choke thermostats ranging from $12 to $25 for replacement styles. The guy on ebay I messaged he wants $100 for this one but he has it listed at $120 + $8 shipping but ive found his photos same 3 on four other sites selling the same part number thermostat with pricing range from $35 to $85. Makes me wonder if the guy is trying to get all he can or if someone lifted his images and are using them on fake sale ads.
 
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I think you should contact scicala on here. He’s very good with the carb stuff, or he might just post your answer shortly.
 
Rusty_S85 said:
. . . The choke thermostat I have now doesn't have the locator mark on it so I don't even know where index is at so I cant even tell where the thermostat should be set at initially.
. . .
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My aftermarket choke cover doesn't have an index mark either. I probably wouldn't rely on it if it did.
I open the throttle about half way and turn the thermostat cover until the choke plate has just closed when the engine is cold, then fine tune it from there if I feel the need.

I agree with the scicala suggestion, his little finger knows more about carbs than I ever will.
 
Another thing is I got a choke thermostat that came with this reman carb, reason I am not running it is it rolled off the table onto the floor and has a crack in it now. Not sure if something like that can be fixed to prevent a vacuum leak. But this one is I think a oem factory one as it has the 56M on the middle of the plastic cap and the inside uses a brass stud for the choke coil to fit into and hammered with a flat screwdriver to lock it in place. The NOS ones I found they don't have this brass center peg but a plastic so this is probably a factory unit which I rather use but not sure if this plastic housing can be patched to stabilize it and make it useable without any issues.
 
dmsfrr said:
My aftermarket choke cover doesn't have an index mark either. I probably wouldn't rely on it if it did.
I open the throttle about half way and turn the thermostat cover until the choke plate has just closed when the engine is cold, then fine tune it from there if I feel the need.

I agree with the scicala suggestion, his little finger knows more about carbs than I ever will.
Click to expand...

What hurt me on the one I am using now is it came off my holley 4000 that is original to the car and this one is some replacement style but it fits so snugly its very hard to turn it so I cant tell how much spring tension I have on the choke.

The choke cap that was on the reman holley 4000 I got ended up getting cracked when I had to disassemble the reman carb to swap my choke housing from my old carb to the reman as they chopped the threads off the choke housing to put a choke saver on but never installed the saver.

If I could some how patch this one I rather use this as this looks like a factory unit with its plastic construction and brass center pin to lock the spring in place.
 
Dobie Gillis said:
Can you patch it up with JB Weld?
Click to expand...

I probably could. Maybe could even use a soldier iron and melt the plastic together. Its just a crack that is a hair line piece that goes through and though and through I don't know if it is cracked enough to leak now but with heat I don't know if it would start to leak from expansion.
 
The cap with "56M" embossed on it is the correct one for a '56 Holley 4000 for Ford, T-Bird, Mercury and Lincoln. It's mostly unique because it is rotated counter clockwise to open the choke (lean direction). All other later holleys are clock wise to open the choke.
If your current cap is just cracked and the brass post for the bimetal spring isn't broken off, it can be repaired with JB Weld, sanded, then painted semi-gloss black. I've done it a few times and works well.
If you use a replacement cap without an index notch, it's not a big deal. Just do exactly as DMSFRR said in post #5 to set the choke cold (aprox. 70 degrees F + or -).


I also have an NOS choke housing if yours can't be repaired. Not real cheap though, since they are as rare as hen's teeth, and most carbs have the hot air tube threads trashed.


Sal
 
scicala said:
The cap with "56M" embossed on it is the correct one for a '56 Holley 4000 for Ford, T-Bird, Mercury and Lincoln. It's mostly unique because it is rotated counter clockwise to open the choke (lean direction). All other later holleys are clock wise to open the choke.
If your current cap is just cracked and the brass post for the bimetal spring isn't broken off, it can be repaired with JB Weld, sanded, then painted semi-gloss black. I've done it a few times and works well.
If you use a replacement cap without an index notch, it's not a big deal. Just do exactly as DMSFRR said in post #5 to set the choke cold (aprox. 70 degrees F + or -).


I also have an NOS choke housing if yours can't be repaired. Not real cheap though, since they are as rare as hen's teeth, and most carbs have the hot air tube threads trashed.


Sal
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Thanks for the reply, this one is just cracked. I did try to remove the spring to use it on my other cap which isn't factory but wasn't able to and left it alone and its not broken I took a flame and let the heat rise up to the coil to make sure it rotated the right way and it seems to function properly.

Only thing wrong with this cap is there is a hair line crack on the outside that you can feel with your finger nail. I can run to the auto parts store tomorrow and pick up some fresh JB Weld or what ever and try to patch it. This crack is on the side of the thermostat housing not the face so might not be that bad of a place for it. Just didn't want to use it as is cause I wasn't too sure if that could cause me a problem having me chase my tail trying to figure out the problem.

The choke housing I got the one off my other Holley 4000 that is original to the car that I will be shipping out later on to restore. The threads are crossed on this one but it seals and works for me as of now. I know they are hard I found one guy on ebay selling the whole choke assembly for $250 nos but it has the clock wise rotation choke thermostat not the counter clockwise rotation one like I need.
 
If it's just a hairline crack without a visible gap, I wouldn't even JB Weld it. There's not a lot of stress on it, and even if the cap is broken, the vacuum leak is not enough to notice anything. It normally pulls a little vacuum to pull the hot air through so it heats the bimetal spring.
Sounds like your all set then.


Sal
 
scicala said:
If it's just a hairline crack without a visible gap, I wouldn't even JB Weld it. There's not a lot of stress on it, and even if the cap is broken, the vacuum leak is not enough to notice anything. It normally pulls a little vacuum to pull the hot air through so it heats the bimetal spring.
Sounds like your all set then.


Sal
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Oh yea there is no gap. I was just afraid that once warmed up it might open up I don't know how this old plastic will react. The old timers from the tech classes I took years ago they acted like a cracked choke thermostat means it is time for the trash cause they will leak vacuum.

I did order for local pick up some of that 5 minute JB Weld Clear Weld epoxy in the syringe. I can take and brush a thin layer on it if need be but if you say it wont cause a problem I can run it as is. Just don't want to cause problems for myself trying to get this engine to run properly.
 
Even with heat, the cap can't really expand enough to expose a gap in the crack since the cap is surrounded by the three tabs (with clamp down screws) and will keep it from expanding. I think your good to go the way it is.


Sal
 
scicala said:
Even with heat, the cap can't really expand enough to expose a gap in the crack since the cap is surrounded by the three tabs (with clamp down screws) and will keep it from expanding. I think your good to go the way it is.


Sal
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Thanks for the reply. I decided to try out this two part clear epoxy from jbweld this stuff I read was thin. I used a toothpick and got a thin layer to where it seeped into the crack. Going to hit it with some fine grit paper in the morning and throw it on. Wont need to paint it or anything I got the metal shield that bolts on the 4000 to protect the thermostat from getting hit that will cover up most of the thermostat and hide the clear epoxy.

Cant work on the car today anyways to run the new vacuum lines and install the new bulbs in the dash with all the rain we have.

Now if only larrys would get me the heater gasket set I can pull my box put my new heater core in and install my new nos heater control valve.
 
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