Doug,
I'm certainly guilty. I just got my 2" pipe flange. Will take it down to my local machinist for trimming and bolt holes. McMaster even had a high temp(800 degree) gasket for the flange. Flange will bolt on, then 2" npt threads from there on. Will take a standard 2-3/8" ID muffler pipe, which are avail on ebay for diesel tractors. Will also check local parts stores, might get one cheaper.
The Intake side has a two hole flange mounting. Figure I can make a matching flange and weld it to 2" pipe and I can put the same muffler on the intake side. Would be easier to mount intake muffler inboard of the air filter. Would this likely work?
From your pics of Gus, doesn't look like there's much you haven't rebuilt or replaced. Ol' Gus should run like a Swiss watch when you get him back together.
ZEKE
Zeke,
I believe the very best performing type of muffler you could put on the intake is a long glasspack or better a steelpack. I haven`t been able to locate one of those. It will work fine on the engine side of the air filter but may shed some of it`s glass fibers into the engine and there will not be a filter to catch them. That is my only concern with a muffler after the air cleaner. If you do this keep the line length between the muffler and air filter as physically short as possible for least noise. Length from silencer to intake valve is not so critical noise wise. I mentioined steel pack thinking it would be less likely to shed fine abrasives like a glasspack may.
I would not use a reactive muffler for an air inlet silencer due to excessive insertion loss to flow. Going very large bore here will reduce flow restriction but may not be particuarly effective, or simply overly expensive.
If you have access to a machine shop you can make a really effective silencer from a 100 lb. propane tank with a 3 inch diameter perforated center pipe brazed down the center. As for tools you could do the whole job with just a cutting torch and brazing tip. Reduce to 2 inch to fit your intake manifold pipe on inlet. Mount the air cleaner on the other end. Fill the space between the tank and the center perforated pipe with pink fiberglass batting, or even better, rockwool. Stuff like a fluffy pillow, fairly tight, not loose. I guarantee virtually no sound from the inlet with this silencer. If you only use this silencer as an intake silencer you could roll the center perf pipe section from very fine brass mesh sieve and solder it along the seam. That would keep glass fibers from entering the airflow to the engine.
When cutting open a used propane tank I always fill with water first to reduce the explosion hazard to zero.
I made one of these using a rolled piece of diamond mesh steel sheet down the center as a final muffler for my VW genset. I brazed the mesh seam. Although mine employed a rolled outer steel skin 4 feet long and the ends cut from a 20 lb propane bottle, the size of a 100 lb bottle is perfect and less work. The first muffler in my VW diesel plant is a regular reactive car muffler near the engine. The Glasspack is at the very end of the 2-1/4 inch 12 foot vertical run through the roof with a flapper on the top outlet to keep rain out. At full load I hear zero exhaust noise when standing next to the muffler on the roof. This is what they would classify as a hospital grade or better silencer. The only clue of the engine running outside is a faint hum of the metal building wall vibrating and a whisp of exhaust smoke when there is no wind. I plan to deal with the wall re-radiation when I have the $$$ to redo and improve the actual generator room with improved wall treatments and new interior walls to make the generator room bigger to accomodate the other generators (Petter PJ-1 and Jiang Dong 175) and related equipment, presently in yet another room and not so quiet..