No, wait! What I meant to say was, "What do you do when removing a generator and your jack goes up to 16", but the genset is at 24" ?"

Threaded rods to the "rescue"! Clamping the crossmembers to the genset mount, I removed the bolts and replaced all four with 18" of 1/2"-13 threaded rods, which I had on hand. Well, I did after cutting a 72" rod to the sizes.

After lowering, it looked something like this: (Actually, it looked exactly like this!)

And like this:

FREE AT LAST! Now I have to clean up and reinforce considerable rust on the front bumper crossmember, but I be headed for the finish in about a week! BTW, the square hole is for a front hitch receiver that Conrad used to tote bicycles. I removed it to give me more room, which, with the enclosure for the Honda genset, will be a bit tighter.

Yeah. I used a jackscrew to do my engine change, too. I don't think you're dealing with as much weight, but motorcycle chain lube can prevent galling of the threads under load.

There was an estimated 55 lbs on each rod; a bit of motor oil works just fine, as it has HD additives, which chain oil doesn't - as long as whatever sticks to the threads, it's fine; nevertheless, the rods would likely do fine with no lube at all, since the stress is so minimal.

The Honda weighs about the same, and I tried raising the Kohler to see if there was a noticeable stess, but there wasn't. Just time-consuming.

We have a 4kw honda in our breakaway. Not very happy with the noise, so waiting with open ears to see how you get it to quite down.
When we got it was fueling from a 6 gallon outboard tank located in the left bay. 6 gallons is not enough so found a 16 gallon marine tank which just fit the long shallow bay just behind the right front wheel.

Gary, do you notice the exhaust noise or the mechanical noise or the fan noise?

On my 6010 Honda, the whine of the fan noise bothers me the most. My approach to gensets is to first recognize that there are two groups of people to care about. The people inside and the people outside. Addressing the people outside, we must recognize that the enclosure area needs big holes to let air in and out. This means a lot of sound cannot be blocked, just absorbed. I use a compartment liner of high NRC rated material and make both the inlet and exhaust air take a turn or two in a duct lined with the same material. Sound tends to travel line of sight, so absorbing it as it is forced to turn is effective. I am going to install my Honda a little higher in its compartment to allow enough clearance underneath it for a sound absorbing chamber for both inlet and exhaust air. My measurements indicate that a lot noise emanates from the underside.

To block the genset sound from traveling through a wall, to the interior or exterior, or as with a doghouse on a puller, I use a high STC rated material. A high STC material will also be most effective in keeping the sound from coming through the walls into your coach. The best high STC materials have a heavy layer of lead or mineral-loaded vinyl between two layers of foam. The foam can also contribute to the NRC rating. Seldom does one material excel in both STC and NRC ratings. Unfortunately.

Sometimes I carry a piece of soundboard from Lowe's that I lean on the side to protect my neighbors.

I have measured the same genset front-mounted in two different coaches, and found that the open grille area affected the noise reading by several db. These things usually need an inlet area of only 150 square inches or so, so there is a lot of easy quietening available right away. I took several decibels off my Kohler Klanker just by using a high STC piece to block the grille. They call for way over a hundred square inches of inlet area, but it is surviving quite well on the 90 square inches that it gets from the gap between the door sill and the mounting plate. It is possible that we might come a cropper if we ran both air conditioners in hundred-degree weather, but we almost never run the air, particularly during the day. Right now, my meter indicates that the most noise is coming from underneath where the cooling air comes out. There is some stuff gonna be stuck unnerneath pretty soon.

Rusty, I know you are doing some soundproofing, .....do you think we should have a separate thread for this?

Dave?

Might as well keep it here for now - my soundproofing scheme is having to go to Plan "B". I made a mockup of the enclosure to test the fit using Ultra Barrier Plus, but since it's 1.4" thick, the proposed enclosure is a bit too wide and a skosh too tall. I got a 4'x4' sheet of seconds, which now I can't use, so it'll be posted in the Swap Meet Central forum.

So now I'm looking for an alternative in the 1/4"-1/2" thickness range.

Any suggestions?

quote:

Originally posted by bill h:
On my 6K Honda, the whine of the fan noise bothers me the most.

For some reason I overlooked this item before.

However, I have good news and I have bad news. My EV-4010 (same exact engine, just run at less power, assuming you have the EV-6010) had the same issue - the whine almost overpowered the engine noise. I suspected a bad bearing in the fan motor, but the bearing was fine (this is not an easy disassembly, BTW). And this is a VERY strange design!

What I discovered was the lands on the armature's non-brush side were rubbing on the casing. In the photo, one spot burnished can be seen about 6:30 halfway or so from the edge on the area of the "spokes" - the armature is the center thingy.

Replacing the motor cured the quite loud whine, and it's a snap to do. That's the "good" news. The "bad" is that the motor lists for $260 - even with my discount, it was $179!

quote:

Any suggestions?

OW!

Those are tight clearances. Is your enclosure going to be sheet metal or MDF or what?

Either way, providing a bending path for the air in and out, with that path lined with high NRC material might yield a lot.

Given your thickness range, you might look West Marine. They have a constrained layer material in 1/2 thickness.

Or consider econobarrier from your supplier.

And, take a look at Owens Corning Quietzone acoustic floor mat. It is 3/8 or so. Closed cell polyethelene.

You and I seem to differ on how to cut gen noise. You are taking the path of stopping sound from leaving through the walls, and I want to absorb the sound before it leaves through the holes. Both are necessary considerations, and the only difference is how we weight them, and what yields the most return for the time, money and space. I have not done a controlled Science Fair project on this, so can only go by Kaintucky Windage and intuition. The large stationary generators I have examined do both.

I do know one fellow who did all he could do with a 4010, and ended up installing a rearward-facing air outlet for the cooling air. It looked like a big air scoop underneath, except facing rearward. He has gotten pretty good readings (57dbA @ 20 ft). He also likes the Supertrapp 5S muffler with its dedicated resonator on the end of his exhaust, in addition to the Honda muffler. I have the 3S with resonator, and it is available cheap. It is only good for 1 dbA at 20 ft. I will be using a spark arrestor with my Honda muffler, so, pending accurate information on back pressure limits, I am a little chary about adding any more back pressure.

I'm considering a rear-facing air scoop for the radiator discharge, to lessen the stress on the fan motor while underway.

My enclosure will be sheetmetal (16 ga.), with 1"x1"x1/8" corners.

I think we have no disagreement on reducing noise - perhaps a bit of discord on what is producing it. My Honda muffler has a spark arrestor installed, and I have a resonator culled from the Kohler; I'm with you - too much backpressure could be an issue, but not so much on gaso engines (as compared to diesels). Already, sitting on its cart with the muffler attached, the EV-4010 is far quieter (by ear - no readings have been yet taken) than the Klunker. Actually, the Honda without a muffler was quieter than the Kohler. I anticipate taking sound-level readings on the bare EV-4010 tomorrow (if the wind will die down). Hopefully, the enclosure will quiet the Honda by another 2 or 3 db.

In any event, the Honda will be significantly quieter than the Klunker, and most important, I won't have to drive 80 miles round-trip to fill the LPG tank (while sweating out what will warm up in the reefer!) when at the Nebraska Star Party.

Here are my Radio Shack SL meter readings on the Klunker:

Driver’s side: 3’ 88db 10’ 79db
Front: 3’ 91db 10’ 85db
Passenger Side: 3’ 93db 10’ NA (could not get into woods)
Inside Front - 82db Inside Ambient: 55db

Oddly enough, the exhaust is on the driver's side, but the highest SL is on the passenger side. I'm expecting at least a 8-10 db relief from the Honda. We shall see!

No matter what, I just like Honda ensembles better than Kohlers...

quote:

My enclosure will be sheetmetal (16 ga.), with 1"x1"x1/8" corners.

Gadzooks! Now we have a metal diaphragm drumming away, as well. I have had good luck with 3M spray on undercoating on metal stuff. Dynamat is way better, but takes up space.

This will sound silly, but pressing coarse sand into tacky undercoat and then spraying another layer can make a big difference. Each grain of sand acts as its own little heat engine, converting the mechanical energy to heat. Ummm, don't ever get me started on speaker enclosures.

Something else that is quick and efficient, is th light gray stick on anti skid material. Not the stuff that feels like sandpaper, but kinda rubbery. It has yielded stunning results for me. In addition to its resonance damping properties, its rough texture provides a multitude of points for sound waves to launch themselves into space, rather than traveling to an edge and being much stronger.

Stainless sink manufacturers use litte stick on patches that do a wonderful job in damping garbage disposal noise. They also dampen spurious resonances in CD players.

quote:

Passenger Side: 3’ 93db

Applying the inverse square law, that works out to 76.5 dbA at 20 feet. Loud. What load was the gen pulling? My measurements of a number of other Barth pushers indicates that front mounting is way noisier. My 7K Klanker in its compartment with a big hole in the door used to be 69 dbA.

Now, with a small glasspack muffler added, the exhaust aimed under the rear bumper, and the air inlet opening blocked by a 1 inch thickness constrained layer material, it reads several db lower, but I have not taken a reading under good conditions since I did it. Low to mid sixties, I think. I now need to do some work underneath. I think I am going to use Knauf 1.6 PCF lining easily bendable sheet metal. With undercoating, of course.

I took the sound readings from the Honda today at 1/2 load. The Kohler was measured at no-load. Measurements on the Honda were taken bare at distances from the genset edges, not from the sides of the coach (since it's still on its dolly):

Driver's side: 3' 88 db 10' 81db
Front: 3' 86db 10' 80db
Passenger's side: 3' 81db 10' 80db

These are actual readings - because of the wind through the trees, realistically, these should be reduced overall by 2 db; the Kohler readings were taken in a flat calm. Also, the exhaust was pointed to the Passenger side - a jury-rig - but the final will send it to the driver's side.

This difference makes me pleased - I think once installed, the SL will drop another 7-10db. I won't hit Honda's spec of 67 db, but the Honda will be far less intrusive than the Kohler.

Anyway, I'm considering AFF-0500 faced foam or Quiet Barrier which has a pretty decent STC of 32. I appreciate your noting the spray-on products - which I considered - but the enclosure will be aluminum, and I don't do well in getting coatings to adhere to AL...paint, yes, anything else, no. However, I've also thought about coatings for the outside of the enclosure, in addition to the suppressing materials inside - so you've given me a definite lift!

One thing I've noticed about the Honda over the Klunker is that the sound is less staccato - less irritating - more of a "whoosh" than The Anvil Chorus of the Kohler.

quote:

Quiet Barrier which has a pretty decent STC of 32.

Hmmmmm............An STC of 32 seems quite remarkable for foam of that thickness.