Onan Exhaust

[ole496 0]

Hello again, I am in need of repairing my exhaust on a 20HP Onan. I believe the pipe size on it is 1 inch OD. Anyone know of where I could buy some new section of this size pipe? I cannot find it locally, even at the largest metal/welding supplier in the area has no idea according to them. I am looking to add new pipe to the existing manifold pipes that connect to the engine. The muffler is gone and all I have left is the pipe. I'm planning on adding some pipe and adding an increase section to a 1 1/4 inch pipe so I can add a tractor muffler. I know I can buy the $400 dollar manifold part from Toro but I'd rather not spend the money on that. If anyone has any ideas let me know. I've struck on e-bay lately and I need to do something to get this running. Thanks again!! Mike

[jerrell 1]

hello ole 496, have you tried the muffler shops, in my small town, they are used to farmers bringing parts in to make bigger and smaller for them to weld on their tractros. they have a expander to stretch the pipe ends and a crimper to squeeze them together. I am in the same perdickerment with a 20 hp honda, but need the parts that bolt to the engine, keep trying to find an old muffler and cut the mounting hardware off and weld my pipes on, all i find is rusted junk so far, :thumbs:

[TT-(Moderator) 1,127]

Here's two suggestions if you need 1" O.D. tubing:

Hydraulic tubing or Harley Davidson handlebars.

Conduit will work in a pinch, but it comes in odd sizes that may need a little slitting, crimping, and welding to get it to fit standard black pipe. It's usually galvanized, so welding can be a real pain unless you burn it off first.

[ole496 0]

:whistle: Good ideas guys! I tried the local muffler guy but not much help there. He did bend a pipe and weld it on for me which is how I got the muffler on it. But it's only a temp fix for now, but I can't leave it that way. I used the other guys setup when I bought it and it looks really bad. He poorly welded a pipe on it then bent it in storage. The threads were stripped out of one side of the manifold so I retapped it and fixed it good as new. 2 new muffler gaskets and away I go! It's functional now at least. My goal was to remake the entire manifold pipe from scratch which is why the right size pipe would come in handy. It's been so cold up here all winter that it's nearly impossible to work on anything! My other option might be to hack up the one I have and salvage it and start from there...but I really need the pipe. In my other WH forum someone suggested try Aircraft Spruce (Aircraft parts company). I checked them out and they sell all kinds of tubing and metal. I might be able to get something there? Thanks again, Mike

[TT-(Moderator) 1,127]

Since you already have the two "headpipes" , why not get a piece of 3 or 4 inch pipe from the muffler shop and mount it horizontally across the ends like the OEM muffler?

If you weld a cap on each end and cut an outlet in the center of the front cap to insert a baffled pipe, you'll basically have a replica of the stock exhaust. :thumbs:

[ole496 0]

:whistle: I think that might do the trick. I see you have a nice looking WheelHorse in your pic with a big muffler on it. How did you pull that one off? This is my first attempt at fixing an exhaust system. I usually just sandblast and paint stuff and occasionally powdercoat parts. So far this exhaust has been a head scratcher for me because I'm new to metal working. I have access to welding equipment but I don't have a pipe bender, etc. All I know is that the muffler set up on this is embarrassing and needs to be right. I think I've got some good ideas to work with, Thanks!!

[TT-(Moderator) 1,127]

Here's a half-decent "reference picture" of the muffler on the 520-8 I used to own:

The vertical exhaust stack can be done in a few different ways, but I chose to use threaded 1" black pipe (tack welded at the connections to keep it from turning) and a Farmall Cub muffler from TSC on my narrow front Charger: