Langdon Stovebolt Dual Carter Carbs, Exhaust Questions!

[Don Coatney]

Also,

What all do you guys recommend for splitting the fuel line to both carbs?

Any sort of junction block in particular? Should I run metal fuel line all the way up, or flex line?

Anything else I should keep in mind? Trying to get everything together before tearing into this!

Not Langdons carburetors but here is how I did my B&B's.

[fadingfastsd]

Heres pics of all the rest of the parts.

Thanks for the pic of the fuel line routing, I will probably go that route.

As for the hardware sizes/lengths....any info?

[fadingfastsd]

Important question guys.

On the Offenhauser intake, what are the 3 threaded holes on the back of the intake for?

I circled them in green here to show you what I'm talking about.

It looks like they're just plugged in this pic...should I just plug them?

Also, what do you guys use as a gasket for the heat plate on the intake?

I have silicone RTV gasket material, and paper/fiber gasket material. Should I use both or one or the other?

The heat plate is circled in blue.

Thanks!

[Don Coatney]

Important question guys.

On the Offenhauser intake, what are the 3 threaded holes on the back of the intake for?

I circled them in green here to show you what I'm talking about.

It looks like they're just plugged in this pic...should I just plug them?

Also, what do you guys use as a gasket for the heat plate on the intake?

I have silicone RTV gasket material, and paper/fiber gasket material. Should I use both or one or the other?

The heat plate is circled in blue.

Thanks!

The center hole is most likely a vacuum port for the windshield wiper motor. Are the two outside holes open to to the vacuum side of the manifold? If not they may be for a water manifold heating system.

[Ryan Robbins]

I actually just got this same intake setup completed on my 47, and just got it running on Monday, so I'll throw in my 2 cents.

I plugged two of the holes on the intake and used one for the vacuum for the wipers. Can't comment about the heat riser, as I have the stock exhaust with 2nd dump added for duals.

I ran my hard gas line up to the first carb and with a "T" fitting ran a soft line to the 2nd, not sure if its right, but it works!

I did have some problems with the fit of the intake and had to file parts of the flanges down so the bolt would fit between it and the exhaust flange.

I was also not impressed with the linkage I received. I could not screw the threaded rod completely into the pivot attachments. I also had to make a 90 degree bend for the plates that attach the linkage to the carbs. The straight plates did not allow for complete opening of the carbs because of the length of threaded rod would hit the connecting rod (not sure if that makes sense).

I am also not getting the secondaries completely open with the throw I have on the accelerator, but am working the issue.

I will say that even with the problems, it started up nicely, runs great and looks awesome. I’m going to try and get some pictures soon.

[Suddensix]

I hooked my B&B's up with a combination of rubber and steel lines through a fuel block.

[woodie49]

Definately a great looking set up. When you go to a dual exhaust, are you running down to your local pipe bender, or is there an exhaust conversion kit or collector out there somewhere? I assume you are going dual all the out the back?

[bkahler]

Important question guys.

On the Offenhauser intake, what are the 3 threaded holes on the back of the intake for?

I circled them in green here to show you what I'm talking about.

It looks like they're just plugged in this pic...should I just plug them?

Also, what do you guys use as a gasket for the heat plate on the intake?

I have silicone RTV gasket material, and paper/fiber gasket material. Should I use both or one or the other?

The heat plate is circled in blue.

Thanks!

The center green hole is for the stud used for the heat riser spring. The stud out of the original manifold screws right in.

I'm guessing the rear hole is for a vacuum wiper connection. Don't have any idea what the larger front hole would be for.

Brad

[fadingfastsd]

I actually just got this same intake setup completed on my 47, and just got it running on Monday, so I'll throw in my 2 cents.

I plugged two of the holes on the intake and used one for the vacuum for the wipers. Can't comment about the heat riser, as I have the stock exhaust with 2nd dump added for duals.

I ran my hard gas line up to the first carb and with a "T" fitting ran a soft line to the 2nd, not sure if its right, but it works!

I did have some problems with the fit of the intake and had to file parts of the flanges down so the bolt would fit between it and the exhaust flange.

I was also not impressed with the linkage I received. I could not screw the threaded rod completely into the pivot attachments. I also had to make a 90 degree bend for the plates that attach the linkage to the carbs. The straight plates did not allow for complete opening of the carbs because of the length of threaded rod would hit the connecting rod (not sure if that makes sense).

I am also not getting the secondaries completely open with the throw I have on the accelerator, but am working the issue.

I will say that even with the problems, it started up nicely, runs great and looks awesome. I’m going to try and get some pictures soon.

I am having the exact same problem.

Im going to have to modify the linkage quite a bit to get it to work correctly. the connecting rod from linkage to bellhousing is nowhere near long enough, it will have to be extended and bent quite a bit to clear.

I'll also have to modify the brackets for the heim joints that the main pivot goes through, as they will not allow full throttle operation at all.

As far as the holes in the OFFY intake, can you tell me the thread sizes if you remember?

I already put the intake on the engine and its all back in the car. I really don't want to pull the intake again, but I forgot to get plugs for the holes.

I don't need any of them open.

If you could tell me the thread sizes I'd really appreciate it, will save me alot of trouble. I'm assuming they are coarse threaded like the carb mounting holes and heat plate were.

Also, for the water heating, how did you guys T into the hot water? There are no provisions for it at the thermostat or water pump outlet. Did you split into the big raditor house somehow?

[martybose]

Also, for the water heating, how did you guys T into the hot water? There are no provisions for it at the thermostat or water pump outlet. Did you split into the big raditor house somehow?

The first question is whether you really need to hook it up; most people don't. If you do, the easiest way is to get water from the heater connection at the back of the head and dump it back into the water pump at the heater hose connection.

Marty

[james curl]

Suddan Six, did you make the carburetor spacers that raise the carburetors up for the Fenton manifold? George Asche told me to use two Chevy 235 I6 carb insullators to raise the carbs up to increase the torque. I had them mounted to the manidold and it was a revver but lacked low end torque, two 1/2" spacers per carb fixed the problem. Yours seem to be at least 2" tall, do you have good low end torque? I also am running a Fenton manifold.

[greg g]

Concentional wisdom is to split the heater hose for a feed. You seem to have your heater hose return blocked. most use theretrun line spliting on its ru from the firewall (P15) back t the top of the water pump. So the manifold would get the coolant returning from the heater. Guess the heater would need to be on. Cold weather driving would necessitate a rather long warm up period before the manifold would benifit. Summer driving would necesitat haveing the heater on. Probably why most folks don't hook them up.

[Young Ed]

Why would you not split the supply line then? Or create its own supply line seperate from the heater? It can't be that hard to create a second tap into the water system.

[blueskies]

Why would you not split the supply line then? Or create its own supply line seperate from the heater? It can't be that hard to create a second tap into the water system.

This is what I did for my Edmunds dual water heated intake. I put a "t" fitting in to the supply line that runs to the heater, and another in the return line that runs back to the water pump.

The "t" in the supply line is oriented so that the flow is straight through to the heater core, and the leg of the "t" runs to the intake. This is so that the majority of the flow will run through the heater when the heater is on, and when it is off, all of the flow runs through the intake.

I drive the car in very cold temps, and the heater gets plenty hot to heat the car comfortably.

It's my humble opinion that the intake heat is important, regardless of your climate. As the air is compressed into the intake by vacuum, it cools. When the intake gets cold, the air/fuel mixture will condense on the cold surface of the intake, and can cause the engine to load up and run poorly. In some cases, the intake can even ice up if there is enough humidity in the air, even on a warm day. Water heat to the intake is great because the intake maintains the same temperature as the engine coolant, and is constant.

I am not running either of the chokes on my dual carbs, as I have found that the heated intake eliminates the need. Even in sub zero temps, my car will start right up, and by the time I get it backed out of the garage, the coolant is warm enough to get the intake warm, and it will idle without choke.

All cars have some form of intake heat, and if it wasn't a good thing, they most likely wouldn't.

In the pic below, you can see the return line from the heater, the return line from the intake, and the "t" where they both run to the water pump. The supply line comes off the back of the head, and is behind the rear carb in this pic. Hit reload on your browser if the pic doesn't show up...

Pete

[Suddensix]

Suddan Six, did you make the carburetor spacers that raise the carburetors up for the Fenton manifold? George Asche told me to use two Chevy 235 I6 carb insullators to raise the carbs up to increase the torque. I had them mounted to the manidold and it was a revver but lacked low end torque, two 1/2" spacers per carb fixed the problem. Yours seem to be at least 2" tall, do you have good low end torque? I also am running a Fenton manifold.

Hi James,

Yes I made the spacers because the studs in the manifold could not be removed and were not long enough to accomodate the cab and the Geo. Asche linkage. As far as torque is concerned I can't say I notice a great deal of difference until third gear then it really pulls hard.