| Author | Message | ||
| Brian Brown (Blue_velvet)
Rating: N/A |
I've been promising the Board to get up some pics of my diesel genset shoehorn exercise from August. I've been too busy travelling and working to get it done until now. Here's a page of primarily pics and some notes without too much detail. Feel free to post questions, comments, slings and arrows, etc. either here or off-board. It's a BIG page, so dial-uppers... sorry in advance. http://www.brownland.org/bus/genny/ Enjoy, Brian Brown PD4106-1175 Longmont, CO USA | ||
| Tim Strommen (Tim_strommen)
Rating: N/A |
It's cute! Here's the $2,500 question though: Is it quiet? I didn't see any sound insulation... I'll also note that I didn't see any isolator mounts to "float" the genny frame from the rig's chassis - this kind of isolator is the cheapest, easiest way to make the genny (via frame transmitted sound) quieter. Isolators can be had for less than $5 a piece - well worth the investment (find some isolators HERE at Grainger - they are bound to have a local shop in your area). Cheers! -Tim | ||
| Brian Brown (Blue_velvet)
Rating: N/A |
Thanks, Tim. No... the thing is freakishly loud! 3,000rpms will do that. Some sort of sound attenuation is on my to-do list. It'll probably only help so much... The isolators are there. You just can't see 'em. They're stock and on the stock baseplate of the unit... big old rubber things with a metric bolt through 'em. I hacked the baseplate up and put it under the thing and it does help, I'm sure. For my budget, I'm pleased. If I had twice as much to spend, I would have gone with a traditional 8kW Kubota or Isuzu (1,800 rpm)... and might be able to sleep with it on. Maybe on my next bus. As it stands, for our current plug-to-plug lifestyle, I can barely hear it when we're running down the road. For the occasional morning after an overnight at Wally-World in-transit... if you value your sanity, avoid parking near the old blue bus!  Thanks again, bb | ||
| David Hartley (Drdave)
Rating: N/A |
Might want to look into changing the pulley ratio so the engine runs at 2,200 rpm and the head runs at 3,600 rpm It will cut that noise down quite a bit. Or... Find an 1800 rpm head that will fit in the space of the old one, then change the ratio for engine at 2,000 and gen head at 1,800 Just some idle thoughts... Poor mans sound material is 1" fiberglass duct board and will nock out a lot of the high frequency noise. Used it on a 2-cyl 3,600 rpm contactor set once before I went to water cooled stuff. | ||
| Tim Strommen (Tim_strommen)
Rating: N/A |
Ah, yeah I see them now. Due to the age of the isolators, you may want to look into replacing them anyway, as they can become brittle/hard with age. The next thing you can do to knock down some of that noise is the use a mineral fiber "batting" to kill some of the high frequency sound, and a limp-mass (like Rhino Liner, Line-X, NoiseBlok, Dynamat, etc.) on the bulkheads (walls) and bay ceiling and floor for the low frequency. You may also want to see about putting some baffling for intake and exhaust air (not the actual exhaust from the engine but the engine cooling air radiator air). This should knock down the sound levels by about 50% or so (3db). Cheers! -Tim P.S. Looking at the pictures I thougth I saw copper lines coming out of the fuel tank that were "zip-tied" together - if this is the case you should put some form of intermediate material to keep the lines from rubbing directyl on one-another as that type of wear will accelarate the failure of the fuel delivery system (read as "fuel leak"/"possible fire"...) -Tim | ||
| JR
Rating: N/A |
I've got exactly the same Yamaha generator installed in my MC9 and it is definitely loud. It's not bad inside the coach, but outside is an issue. I bought some 1" rubbetex (however it's spelled) and plan to remove the genset and re-insulate the condenser compartment. The unit is sitting on rubber isolators, and they are less than a year old. The panel behind the wheels are transferring sound in some fashion. The generator is louder on the curb side than on the street side...yet it's mounted in the street side condenser compartment. Radiator blows out thru the old condenser fan hole. Not muffler noise...just harmonics. A friend has a big Kubota that's quiet, but it utilizes the front street side bay. I'd rather have the noise than give up a bay. Only have two bays left with holding tanks using all of rear bay. Storage space is more important to me than noise. I'll be interested to see what happens (or what works) in the "noise abatement" department. BTW Brian, did you ever get your remote worked out? JR | ||
| Brian Brown (Blue_velvet)
Rating: N/A |
Thanks, guys, for the deadening advice. I'll consult you in the Spring once I attack it in earnest. DH: If I could figure out how to get the little bugger to run at 1,800rpm... that'd be cool. Is that the voltage regulator controlling the speed? The pulley, by contrast, should be cake. TS: That's good advice on the copper lines. I'll get some padding put between them. JR: nope, I had to go on two trips so far w/o the remote start and it's becoming a big pain not having it. I'm leaning toward using the relays (I think that's the way you did yours) to avoid the large loads. I just need a day or so when I'm not working on other stuff to tackle it. Thanks, all! bb | ||
| David Hartley (Drdave)
Rating: N/A |
DH: If I could figure out how to get the little bugger to run at 1,800rpm... that'd be cool. Is that the voltage regulator controlling the speed? The pulley, by contrast, should be cake. The pulley idea would work the best. The only potential problem might be how much horsepower your engine can deliver. Check the Kubota website and look up the power curve for that engine, You may not need to run it at 3,000 to get the power to run that 6.5 kw head. Maybe 2,000 or 2,200 would be more in its torque range. Then figure out what the pulley sizes would need to be and change them. The engine would still be overdriving the head a little more and the engine would get a little more loading. But that would be better for the fuel use and noise. As for the voltage/speed regulator since it runs off the generator head it shouldn't cause a problem. If all else fails use the built-in governor of the kubota to lock the speed constant. Just some ideas.... Heck, The guys running the lister-oids are running the 6 hp engines at 650 rpm and gen heads at 1,800 to 3,600 rpm. Now that's overdrive! | ||
| Richard Bowyer (Drivingmisslazy)
Rating: N/A |
BB, voltage regulators control the output voltage of the alternator, governors control engine speed. Richard | ||
| Ron Walker (Prevost82)
Rating: N/A |
Hi Brian ...as Tim said "use a mineral fiber 'batting'". That's what I used. A product called Rocs All Insulation, a rock-wool insulation. I put the batts in the gen compartment and used chicken wire to hold it in place using screws to attach it to the walls and ceiling The stuff is non-combustible, because it's a wool it absorb sound and, with a vapor retarder, helps control condensation and will not support the growth of mildew, mold or bacteria. I all so used it in the ceiling of the bus under the spray foam, I have a dropped ceiling. Ron | ||
| Tim Strommen (Tim_strommen)
Rating: N/A |
Yes, Mineral fiber is a different product from fiber glass. Mineral fiber is usually darker in color (looks like over cooked scrambled eggs), and made of a different material. Since the material is not made of the light glass fibers, it doesn't support a flame as well as say Corning "pink" insulation. Mineral fiber is what manufacturers use in "quiet" generator enclosures - and is what Home Theater installers (like myself formerly) use to control sound. I wouldn't necessarily use it to control condensation - you will start to see moisture build on an interior surface when the exterior temperature is lower than the internal temperature. By having an uncoated metal with a mineral or fiberglass batting of a rigid foam board against it, there is a greater likelihood that the moisture will not have anywhere to go (i.e. - it will be held against the metal). This can be a great cause for corrosion, as this damp metal over time will eventually get a scratch or ding that will give oxidation a good bite into the metal. In this case, the limp mass (think of this like a rubberized paint) usually becomes the corrosion barrier for the metal, as in its typical application, it is somehow adhesively bonded to the metal - which prevents direct contact between moist air and the metal. As no moist air can come in contact with the metal, even if the temperature difference is enough to cause the air's moisture capacity to be reduced and deposit water molecules on the surface - the coating itself will be standing between the metal and the water. There is also an added benefit to the damage resistance, and appearance of the surface that is coated with a spray-type coating These are usually the hidden reasons I advocate for a limp mass to be applied to the underside of a rig, or the inside of any exterior metal - water resistance. Cheers! -Tim P.S. I love you're "Why a Bus?" section on your web-page. everytime someone asks me that question, I refer them to your page. -Tim | ||
| Russ Barnes (Neoruss)
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Reinforcing Tim from real life: Almost the entire engine compartment of my '81 Neoplan Skyliner had double walls and between it mineral fibers for sound control. (Neoplan and Eagle frames are constructed much the same way, just that Neoplan has a few upscale features) My suspicion is that the interior areas had some paint blown around and the steel sheets were pre-galvanized before the spot-welding of the skins, but obviously there still were bare metal areas. In over half the areas I have chiseled open the rust is TERRIBLE and yet on the rest of the bus there is very little. 1 ˝” square (Actually 40 mm square) tubes of about 14 gauge wall thickness were disintragrated. The mineral fibers were still wet after the bus being inside and 100% dry after over a year with heat in the winter and AC in the summer. I know that it is a great soundproofing, but it also is a great sponge. BE CAREFUL USING THIS PRODUCT IN CARBON STEEL AREAS. By the way, wherever I do find any other corrosion in the carbon steel tubes there always were a few fasteners to hold trim, lights or other things. The areas that had no fasteners had very little to no rust inside, even right over the wheels where they had to be wet. In my opinion; if you need to screw something on, weld a tab to the frame and drill and screw to those parts. Water will wick around the threads and introduce humidty to rust from the inside out. | ||
| niles steckbauer (Niles500)
Rating: N/A |
When using screws with any ferrous metal simply dip the thread in butyl caulk - when you drive it, it will seal the entire incursion, remains pliable for a long time, and becomes a vibration insulator - HTH - Niles | ||
| Tim Strommen (Tim_strommen)
Rating: N/A |
Yes Niles, great point! Either the butyl calk on the screw, or drill a pilot hole and squirt some RTV silicon through it creating a blob on the other side of the hole. The spining screw coming through the metal will spread the blob over the area on the imediate oposite side of the hole - a great tip for those who are screwing into a tube or concealed wall. Cheers! -Tim | ||
| Sojourner (Jjimage)
Rating: N/A |
Whatever generator’s rpm is dividing by engine max torque rpm = ratio difference. Example 2200 engine is 1.64 ratio difference then 3600 generator. So engine’s pulley should be 1.64 larger then generator. 2 poles armature is 3600 rpm or 4 poles is 1800 rpm to make 60 cycles. Engine speed is set via it own mechanical governor which is adjustable. To calibrate; Plug in an AC (alternating current) electric clock with “Second” hand should match minute to minute timing with your wrist watch or whatever clock that running separate from generator. Also plug in a load such as blower or fan or anything of 3 amps or more to make engine works steady load. If clock running faster, then lower engine rpm or ticking slow or late then increase engine speed. High efficiency generator will produce around 125 v @ 60 cycles. Whatever you do, always try to maintain 60 cycles per sec. Otherwise greater difference under 60 cycles electric motor will run slower & labor & over heat. Or the higher cycle per sec over 60, the faster it run & more power & over heat. To save trouble in long run, always maintain at 60 cycles. Like what DMD quote voltage regulator is ONLY a voltage regulator…period. Voltage regulator nothing to do with rpm, unless you have newer variable speed Onan solid-state generator. FWIW Sojourn for Christ, Jerry |