How about 1" EMT (conduit) for exhaust pipe / header?

[jamyers]

Like the title says, how about using 1" EMT - aka metal conduit - for an exhaust pipe, specifically on an 8hp Briggs flathead with 1" exhaust port? I've got a bender, figure I can bend it to just short of a full loop so it points a bit downward (fewer worries about walking into it).

For mounting it, I'm thinking about something like a gasket-pipe-flange setup like on my old cars. Cut out a thick flange that will slip over the pipe, heat and flare the end of the pipe out to just about 90 degrees, making sure the flared end is nice and flat. Use the Briggs flat gasket (or maybe 2), and the flange bolts everything up to the engine. No welding, and not only can I change the clocking of the pipe in the future, I can replace the pipe if/when it rusts through.

 

[jamyers]

Never mind, I did some forum searching...

 

[slideways]

Don't you have a threaded exhaust port on that motor? I always had success with a 1" piece of plumbing pipe in there. Install it and then warm the motor and tighten.. otherwise it will wiggle free. Then install a header brace. Don't worry about loss of performance. The exhaust port on the Briggs Flatty is notoriously too big even stock so filling it with the threaded pipe won't hurt. If you ever went with porting/carb work/cam then you may want it opened all the way.

 

[jamyers]

I'd rather avoid a straight (long) exhaust pipe, rather go with a curved almost "trumpet" kind. What I'm imagining is a pipe coming out, curving up and around to nearly a full loop, with the end aiming 10* below horizontal.

 

[slideways]

Ah ok.. there will be bending involved there. I used to just use the plumbing fittings when we made "custom" exhausts on lawn tractors and such back in the day.

 

[jamyers]

Ah ok.. there will be bending involved there. I used to just use the plumbing fittings when we made "custom" exhausts on lawn tractors and such back in the day.

I'm with you there - you should see the exhaust on my John Deere lawn tractor!

 

[digschopper]

regarding tube bending; i made a sissybar for my chopper out of 1/2" hardware store mild steel tubing. i hade it when it crimps on the inside of a bend,and tried a trick passed on to me by someone with years of experience. fill the tube with clean sand 9i used black beauty blasting grit that was discarded). pack it in tight,and block the ends by welding a temporary plug.you may be able to tap it and put a bolt in.
next,find something to form the bend around. the radius i wanted was the same as the hydraulic shaft on a backhoe (3" dia.)mark the center of where you'll want the bend,and have a buddy heat it cherry red(not bright orange)longer than needed for the bend.
once hot,center the tubes mark on the mandrel(whatever your bending it around) and pull the ends toward you till you get it right. it won't dent in if it was packed tightly enough.now open the ends up and dump sand.oh,and a propane torch won't cut it,you need oxy-acetylene or a forge,although a campfire and patience may work.