Changfa Silencer Added

[Veggiefuel]

Finished my Changfa exhaust silencer modification.
The exhaust noise was reduced dramatically.
Still a lot of pulsation coming from the air inlet. Next experiment is an intake silencer.

Veggie



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[lowspeedlife]

very nice Veg, does it vibrate much?
 Also is that one of the nema motor frame adjusters under your generator head? I'm refering to the part in the 2nd photo on the lower right with the number 256B2 painted on it. If so do you like it? does it adjust easily?. Thanks for posting the pics.



        Scott R.

[Veggiefuel]

Scott,

Very little vibration at all. To be safe, I mounted the muffler on rubber hangers.
So far, so good !

You are correct about the motor slide base.
For anyone interested in belt driving your gen-head (Listeroid or Changfa), I would strongly recommend spending the $60 on a motor slide base.
It greatly simplifies the assembly and the belt adjustment.

The ST-5 and ST-7 heads both conform to the dimensions of a 256T frame electric motor slide base.
Just bolt the slide base to the frame, and then bolt the ST head to the slide base.

Below is a better picture showing the slide base (prior to the muffler mods).
The vertical frame to the right of the gen head is the future mount for the electrical/instrument panel.

Cheers,
Veggie

[rford85165]

do you know the part number for the muffler you used

[SHIPCHIEF]

Yes,
It's always important to get the pictures taken early while everything looks nice..

[jzeeff]

Has anyone gotten one of these to run in the 75 dBa range?

[mobile_bob]

i got my s195 down to just below 70db

of course that was with a nice set of earplugs!

hahahahaaaaa

(sorry i couldn't resist)

bob g

[SHIPCHIEF]

How about the mechanical noise?
I had an old Kohler 4 Kw that was pretty noisey. I shielded the noise with an A frame of pallets and covered it with carpet scraps. That attenuated the mechanical noise during a week long power outage. Kind of cheap, and thrown together in a hurry, but it helped.

[europachris]

There is lots of mechanical noise. I will be building a shed.

Henry

I used a Solberg air compressor intake silencer/filter on my R185 set and it really reduced the noise level from the intake, as well as being a far better quality filtering device.  I made a custom intake manifold and coupled the pipe thread on the filter to the manifold with a short section of radiator hose so the engine vibration can decouple from the silencer and not cause cracks in the manifold over time.

I also ditched the stock muffler and welded on a big round one from NAPA.  All I hear from the exhaust is "fluff-fluff-fluff-fluff".  The intake is still fairly loud, but the mechanical racket this thing produces is incredible!  Here it is powering the house one afternoon the day after a storm.  Electricity was fine until about 1pm, then "poof".  Took until 11pm to find the problem and git it fixed - it was a real isolated failure for just half our subdivision!

[Wizard]

Changfa noise is because of the tin covers under gas tank, crankcase and oil pan, what about valve cover?  If one makes covers out of thicker materials like 1/8 or 3/16 even billet covers.  Or weld pieces of thicker metal diagonally like X's on all sides of these to stop drumming action etc.  Increase the intake muffler size even use another exhaust muffler?

Engineers of 2.2/2.5 had to develop audio damping oilpans (2 layers of sheet metal and plastic sandwiched between). added series of holes in the stamped crank pulley to move the resonances frequencies.

Cheers, Wizard

[M61hops]

I don't think there is any way to quiet a changfa or many other diesels except to enclose them in a sound deadening box!  I had to give up on a Petteroid and a Changfa in favor of a Listeroid due to noise level  .  The Listeroid 6/1 is the quietest diesel engine I have listened to so far even though the pushrods and rocker arms clatter quite a bit.  I may end up putting a box around the 6/1 yet  .  The Changfa and Petteroid both just raidiated loud noise from the cylinder and injuction pump areas!   I guess that I'm hearing the sound of combustion from the cylinder and the cam lobe/rocker smacking the plunger of the injection pump, and maybe the injector makes a noise as it pops open and slams shut  ?  Whatever, I figured starting with a quiet engine puts me that much ahead for a CHP unit that I can run overnight and not disturb the peace too much!  Love the design of the Changfa though!  And the Petteroid looked good but just made an amazing amount of noise  !  Oh well....                                                     Leland

[jzeeff]

Ok, I buy into the box idea.  I suppose the intake, exhaust and radiator lines have to run to outside the box with mufflers on the first two.  Any tips on box construction?

[Veggiefuel]

jzeeff,

If you can tolerate a few less Kw's, the Changfa's quiets down nicely if you drop the rpms.
I built an S195 unit running at 1300 rpm with a 3kw head (I draw 2.5 kws from it) and it makes about 85 dba.
I can stand beside it and have a normal conversation with someone without yelling.
I'm still thinking of putting it in a sound attenuating box because I intend to run it for long periods in a residential area.

Cheers,
Veggie