Quiet muffler - TractorByNet

Is the muffler on your Kioti mounted to the engine? Diesel? If so... you may reconsider touching it.

I worked on a muffler problem back in '93 on the John Deere 430 garden tractor. The muffler had a high service part usage and it needed to be investigated. The mufflers were cracking through the mounting bracket(s) prematurely. It used a Yanmar diesel engine and a muffler which they provided. Yanmar had violated their own design guidelines by mounting the muffler directly to the engine. As it turns out, the high mass of a muffler coupled to an engine with strong firing pulses (like a diesel) creates a fatigue failure nightmare! Some tractors would run to high hours and others would fail within 100 hours... it all came down to the individual engine. Some run smoother than others.

Know that manufacturers do engine/muffler mounting regularly but not without much finite element analysis to pull it off.

Is the muffler on your Kioti mounted to the engine? Diesel? If so... you may reconsider touching it.

I worked on a muffler problem back in '93 on the John Deere 430 garden tractor. The muffler had a high service part usage and it needed to be investigated. The mufflers were cracking through the mounting bracket(s) prematurely. It used a Yanmar diesel engine and a muffler which they provided. Yanmar had violated their own design guidelines by mounting the muffler directly to the engine. As it turns out, the high mass of a muffler coupled to an engine with strong firing pulses (like a diesel) creates a fatigue failure nightmare! Some tractors would run to high hours and others would fail within 100 hours... it all came down to the individual engine. Some run smoother than others.

Know that manufacturers do engine/muffler mounting regularly but not without much finite element analysis to pull it off.

I have a 430 and have had to replace the muffler twice in the last 250 hours of use. The Yanmar is a good engine, but like you observed, they do vibrate/shake considerably at certain RPM settings. After the second muffler broke, I started watching the engine at different RPM settings and figured out why the mufflers were fatiguing and breaking. Now I know where the run the engine, other than wide open, and have over 100 hours on the current muffler with no signs of fatigue cracks in the muffler or mount.
I agree though, the location and mounting on 430s is a bad design.

I have a 10KW genset I scratch built with the same 3TNA72UJ engine as in a 430 uses, and I used a flex coupling between the engine and a frame mounted automotive muffler which works quite well.

Very nice. A Gem of a Generator. I think that flexible coupling might be the right piece to incorportate in a planned upright exhaust for our Kubota M59. It's been rather slowly coming together in my mind. Too slowly compared to most of my projects. I seem to be stuck.

The M59 is a 60hp turbo pre-tier IV & so without emissions complications, but is a sooty engine when changing RPM. In fact, soot and exhaust smell is the main reason to move the exhaust.

my preference would be to run the exhaust over to the right side and up to get it as far away from the operator as possible. Exhaust above the canopy. But moving it that far means more pipe, or using some sort of insulated pipe, & has me wondering just what the limit on pipe bends and length should be.

In fact, not having a feel for the pipe and muffler flow restriction and wondering if the turbo has some requirement there has been a holdup on this project.

Any advice would be appreciated.
rScotty

I have a 430 and have had to replace the muffler twice in the last 250 hours of use. The Yanmar is a good engine, but like you observed, they do vibrate/shake considerably at certain RPM settings. After the second muffler broke, I started watching the engine at different RPM settings and figured out why the mufflers were fatiguing and breaking. Now I know where the run the engine, other than wide open, and have over 100 hours on the current muffler with no signs of fatigue cracks in the muffler or mount.
I agree though, the location and mounting on 430s is a bad design.

Oh man... sorry you've had trouble. It's like hearing one of your children is out terrorizing the countryside.... "what has he done now?"

It's been 30 years; I had just transferred to Horicon Works. I remember working with Yanmar engineers to get it solved (I thought). I ordered high temperature stain gages and rigged a 430 muffler. It was then mounted on a 430 unit from JD's "vault"; it showed acceptable levels when run. Then we borrowed a 430 from a mechanic in Experimental who said he had several muffler failures. The gage'd muffler lit up like a Christmas tree! The Yanmar guys said every engine is different. They made a change to the muffler and calmed it all down. If memory serves, the 430 was a framed tractor with the engine mounted on isolators. That made the design even more difficult as the engine/muffler is more free to move. Maybe your isolators are worn? Sounds like you have found a reasonable solution though.

Beautiful job on the gen set! Good call on frame mounting the muffler through a flex coupling! I know I wouldn't think of altering the engine mounted muffler on my even though it is a mono-block design.