Damage from holes in muffler???

[Mundy]

I looked at a small Iseki today with a 2 cyl Mitsubishi diesel today. The side of the muffle is rotted out. The old fella that has it is in his 80's and did not seem to know it had rotted out. I believe him. For the last 10 years he has only used it to till the garden and his son spread some gravel last year with the loader.

By looking at the muffler it has been rotten for a while. Most of the pieces are still there just laying in the muffler like it rotted and fell in on itself, but some soot is on them and around the holes so I know it has been ran this way.

What damage could result from running with a muffler like this with holes in it?

 

[zzvyb6]

Burned valves from oxygen migration. Basically O2 from outside air 'surfs' its way back to the combustion chamber by riding the backside of the pressure pulse waves. Same reason for not screwing with your truck exhaust by changing length. It's a tuned system.

 

[alchemysa]

Burned valves from oxygen migration. Basically O2 from outside air 'surfs' its way back to the combustion chamber by riding the backside of the pressure pulse waves. Same reason for not screwing with your truck exhaust by changing length. It's a tuned system.

Ow c'mon! You saying that air is gonna flow backwards up the exhaust pipe WHILE the engine is running? I have my doubts.

 

[Pennsylvania Weldor]

Ow c'mon! You saying that air is gonna flow backwards up the exhaust pipe WHILE the engine is running? I have my doubts.

Ditto

 

[allenr]

From my experience I'd say no damage would have resulted from the rusted muffler.

Can't speak for Mitsubishi but if they're anything like a 2 cyl 500cc Kubota I have you can't kill them.

 

[RobJ]

Burned valves from oxygen migration. Basically O2 from outside air 'surfs' its way back to the combustion chamber by riding the backside of the pressure pulse waves. Same reason for not screwing with your truck exhaust by changing length. It's a tuned system.

In other words...

Nothing!

 

[Roger2561]

I agree with the majority responses - nothing will happen other than it running loud. For many years my late father ran a Farmall cub tractor (gas) without a muffler. With 9 kids it was something he couldn't afford to buy. That tractor is running still today. Heck, it's the first tractor I learned to drive. One thing about those old machines, you couldn't kill them if wanted.

 

[zzvyb6]

Well, for example, in case you are wondering why the new Corvettes don't yet have Active Fuel Management, its because the exhaust is tuned for a flow so free that the O2 migration is burning valves when you shut the cylinders off. Sorry to reveal the real world of Combustion Engineering. That's one of the things an O2 sensor in the downstream exhaust of your minivan is measuring, Frank.

 

[alchemysa]

Sorry to reveal the real world of Combustion Engineering. That's one of the things an O2 sensor in the downstream exhaust of your minivan is measuring, Frank.

True, I'm no Combustion Engineer but I still don't buy it. I understand that backpressure can affect how much air gets into the engine via the intake manifold (with a resultant affect on valve life) but the idea that oxygen or fresh air can 'surf' back up the exhaust pipe on the back of pressure waves, while the engine is running, is unbelievable.

To continue the surf analogy, surfers don't go anywhere when they drop to the backs of waves. If they did, they could surf out to sea instead of paddling.

 

[zzvyb6]

Exhaust flow consists of standing waves. Surfers are in a hurry and their waves travel. Ever play with a vibratory conveyer (used for runing pills, parts, rocks, gravel)? Modern exhausts are tuned to make sure this never happens. Google for pix of an engine running on dyno showing header output. You will be able to see the pulse train. Often seen in jet engine exhaust plumes, too. Watch a carrier night launch. Same deal.

Being washed out to sea is every ocean bather's nightmare....