Intake Manifold Extension

[Greg Jones]

I am looking for an "intake manifold extension" to lower a carb that has been adapted to run on a model T. This car belongs to a widow that asked me to help get it running better. Seems it backfires and pops going uphill. I drove it and found this is true, and I attribute it to fuel starvation. You will note in the photo that the gas line takes a couple of sharp turns and then quite a rise before entering the carb. This model T is a gravity feed system, and my conclusion is that the gravity system would work if the carb was lowered by 3-4" or so. Also, this Model T has the gas tank under the driver's seat. You might get enough head pressure if it was a 26-27 with the fuel tank higher in the cowl, I suppose.

So this takes me to my question. Anyone know where I might source pre-fabbed manifold extensions? I know I could get one fabricated but thought if someone is making such a thing already it is worth asking. I also know I could rig up a fuel pump but I don't care to do that.

 

[J Franklin]

Since it has much modification give it a fuel pump. That is what I would do.

 

[Fullraceflathead]

I also agree about adding a fuel pump. That's a highly modified engine and adding 1 or 2 PSI fuel pressure will probably fix the problem of the engine running lean and back firing.

 

[Dan McEachern]

Take a tire pump and rig up a hose to the gas tank cap, put a gasket under the cap and put a few PSI in the gas tank and see if your problem goes away. That will tell you if you have a fuel supply issue.

 

[nkaminar]

For my Model T, I ran a small copper line from the exhaust pipe to the gas tank. The copper line was about 6 feet long and in a loop under the seat. The fuel tank and exhaust pipe can be tapped by punching a hole and then treading it. The tap in the gas tank was at the top. The punch forms a conical hole that is easy to tap and has enough strength. The exhaust is mostly carbon dioxide which is safer than pressurizing the tank with air. The gasoline does not flow back into the exhaust, and if it did there would be no harm. The exhaust added just a few inches of pressure, enough to overcome gravity but not enough to overwhelm the float valve in the carburetor. The exhaust pressure was also greater going up a hill, just when you needed it. You have to add a gasket under the gas cap and epoxy the vent hole. It worked very well for me and others who use the same systems.

You can add an electric fuel pump but you will have to limit the pressure by choosing the right pump or adding a pressure regulator,

 

[nkaminar]

You may get some better answers on the Model T forum.

 

[redmodelt]

I would suggest going to the Model T Ford Club of America's site https://www.mtfca.com/phpBB3/index.php?sid=e75a7d9b4883f357a5fab368716a3102and post there or ask on the Facebook speedsters page. https://www.facebook.com/groups/modeltspeedster/

 

[Gary in MN]

Years ago I ran a Rajo 4 valve and made an extension to lower the carb. About 6" long I was able to use gravity to supply fuel. The problem with lowering the carb is you no longer have warm intake air. Mine ran well for a short time and then the inside would frost up and close off the A/F supply. I removed that intake and went to dual carbs, 6 volt fuel pump and a regulator.