The Stovebolt Site Forums The Shop Area Engine Shop anyone removed the butterfly from the heat riser?

has anyone removed the butterfly from their heat riser? And if so what happened?

It takes a lot longer for the engine to warm up in a cold temperature. It also relieves a lot of back pressure present until the butterfly opens fully. Many don't function properly anyway.
Normbc9

ya think? It seems the intake would get very hot. Apparently not many people have removed them. I know I wouldn't.

There's no substitute for running the engine the way it was designed. A heat riser routes exhaust gas against the bottom of the intake during warmup to keep the richer mixture provided by the choke vaporized. Once the manifolds heat-soak from a few minutes' run time, the extra heat isn't required so the bimetal spring and the counterweight moves the flap valve and routes the gases straight down the exhaust pipe. Backpressure during warmup shouldn't be a concern, unless somebody is in the habit of running a cold engine wide open. Not smart!
Jerry

Oh I'm not going to do it. This was part of another discussion, it didn't seem like a good thing to do. But the other party insists many people do it with no ill effects, I believe the intake would get really hot. But I don't know, as I am not going to do it and find out. I ran mine for many years with no spring, (I didn't even know it was supposed to have one), and it ran just fine, a little cold blooded for a few minutes, but other than that...once as an experiment, I jammed it in the heat position, (I didn't know which was which at the time) oh, very bad idea.