OutdoorKing Repair Forum Forums Restoring, Customising and Modifying Engines Anyone made a muffler before?

Hi all,

I have an old suburu robin 5hp engine that needs a new muffler as the current one is rusted and has a huge secton missing out the bottom.

Now it got me thinking, it's a fairly simple design, I would be able to get away with a 3" bit of pipe for the main barrel, but i'm not sure what to do about the internals? Ideally I would like to keep it running fairly quiet.

Anyone done something like this before? If you have any photos or links please post up.

Thanks

victa, the muffler needs at least one internal baffle even to be vaguely acceptable, let alone quiet. A baffle is a plate transverse to the body of the muffler, with a hole in it out of line with the inlet and outlet ports of the muffler. This breaks up the shock waves inside the muffler. You can make a quieter muffler by having two or more baffles, with the holes not lining up. (A gun silencer typically has ten or more baffles, but has the disadvantage of having to have the holes in line, so the bullet can go through them).

A well-designed 2-baffle muffler in a steel pipe can be fairly quiet, but is likely to trap acids and rust quickly. It can also put excessive loads on the attaching screws due to engine vibration: if it is cantilevered from the port rather than having support brackets, it needs to be very, very light.

Why not just find an old muffler that is suitable with minimum modification?

Hi Victa,
As Grumpy said, it's probably a better bet to get another one. Many mower parts suppliers have "universal" type mufflers that you could use but you would need to match it to what your engine needs (back pressure etc.)

On the other hand, if you want to make it for the pleasure of making your own then give it a go but, again, as Grumpy said - keep it light weight or you will have problems if it is not securely mounted.

I restore vintage stationary engines and have made quite a few mufflers but these are usually of a much heavier construction than today's high performance small engines and, seeing as the engines that I restore never do any real work apart from running at idle speed at shows (rallies to you Aussies) the actual design and performance of the muffler is not as important as for today's engines.

You can see one here for my old 1936 Maytag Hit'nMiss washing machine engine( 2 stroke) Homemade Maytag Muffler and another here for a 1928 Wolseley Wolseley "R" Type silencer

Jerry

Id just buy a muffler for a Briggs and make that fit.


Bob.