carb exhaust heater ?

[Guest rwolf]

I'm trying to keep this car as original as possible but I'm having a problem with the diverter valve that sends the exhaust to the carb. In the fully closed position there is still about 3/8" between the flap and the throat. Before I go to a lot of trouble trying to fix this can someone tell me if this is normal?

[Guest imported_JPIndusi]

The heat riser valve plate can be bent carefully to close with less of a gap. Don't expect it to close perfectly, it just needs to divert the exhaust flow toward the base of the carburetor when cold and out the exhaust pipe when the engine is hot.

Joe, BCA 33493

[Mark Shaw]

Normal or not, unless you are re-building a show car, it is not necessary to make the heat riser functional. It just helps some with faster warm up and when you run your car in cold weather.

Modern gasolines vaporize easily and do not require the heat of yesteryear's gasolines. My 24 Master Six runs just fine without moving the heat control from the summer driving position.

It just takes about five minutes of sputtering during accelleration to warm up;... but I do live in a temperate climate and do not drive my open cars much below 50F.

[Guest rwolf]

Thanks for the advice, I'm not going to worry about the valve closing and will re-install it as is. However the tubes are rusted out and must be replaced. I have tubes to replace the original and it looks like a set screw pushed against a ring

,that goes around the tubes, to hold it in place. In my case these screws have been broken off at the housing and I will have to drill and tap new holes. Am I correct in my assumption?

Also, does anyone know the purpose of the stainless steel lever that goes through the housing near the upper tube?

[Mark Shaw]

My 24 is put away for winter, so I can't take a look or send a photo of the set up, but it sounds like you are describing the heat control linkage.

The lever on the dash moves rods that open and close the exhaust dump valve at the top of the exhaust down pipe near the front of the engine. These rods also change the position of the throttle via a slotted plate on the engine side of the carburator.

[Fred Rawling]

I am not sure what you are referring to as the upper tube. Is it the tube from the carburetor to the intake manifold inside the heat riser? If so, that valve is what what opens when you accelerate. It allows more air/fuel mixture to go into the engine.

I have a 1928 Buick Master. When I rebuilt the engine, I removed the flapper form the exhaust manifold heat valve.

With 800 miles on the engine, I have not had any problems. Heat still gets to the heat riser as was proven to me by water vapor leaking out of the connection from the heat tube to the heat riser.

The collar that goes around the heat tube into the heat riser is used to compress the packing to seal that joint.

I used round teflon faucet packing which aparantly I did not put in properly. I have used round faucet stem packing also.

The set screws that are broken off are 1/4 -20 square head set screws. I bought mine at an industrial hardware store. I could not just buy 2 screws and had to buy a box.

If you can not find just 2 screws and the box is more expensive than 30 cents for the 2 screws and postage from Southern California, Contact me and I will send you a pair.

Contact me at fred.rawling@live.com as I do not check this forum on a regular basis.

Fred