| Author | Message | ||
| Gary LaBombard (Garylee)
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I have posted on another BB these two questions but received no response. Perhaps they are not worth asking to other busnuts like me. I hope I may receive expert information from one of these informational BB's. (1) Can I run my new fuel & return line from the two fuel tanks to the filters at a higher level, (nearest the ceiling) of all compartments to and from the fuel tanks? Will it matter as far as proper fuel flow both ways? I am attemting to enclose all air and fuel lines except for both connecting ends which will be about 12" long and make all wires, hoses and fuel lines in hidden trays protected form all weather and road debris. (2) Will anyone share their gen set mounting information done to insulate & to control sound on your Gen Set compartment to isolate the sound to both in the bus and outside neighbors at camp sites? I want to be assured of proper air for cooling in the compartment to keep the 7.5 Diesel Onan gen set at proper running tempt. but also to isolate the noise of Gen. The Gen Set has it's own radiator and fan also. I know there is sometimes competition at Bus Rallies between you more experienced busnuts on your Gen set compartment manufacturing and I hope you will not mind passing on information to help the rest of us wishing to do the right mounting procedure. How much clearance did you allow for mounting from bulkhead to gen. set etc.? What type of muffler did you use or recommend? Anything valuable on controlling sound and proper mounting will be appreciated. My Gen set is for a 73 05 Eagle, the compartment is on the right side at the aft. end of the bus right now with a screened in type access door which allows all noise out and maxium air in. Thank you ahead of time, Gary | ||
| Nick Morris (Nick3751)
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I'm not to this point yet Gary but on the travel channel about two weeks ago there were several shows about high end conversions. They mounted their gen set on four air bags on a slide out that looked like it was mounted on isolator mounts. Making a double vibration insulated setup to, I would think, almost eliminate vibration in the coach. Also from other post I've read here the more 90's you have in your intake and exhaust the more sound you kill off. Like I said this is all just hear say take it for just that and get some first hand info. Nick | ||
| Marc Bourget Rating: N/A |
Dear Garylee The following is mostly excerpted from notes taken from a Dick Wright (Wrico) seminar at a Bus Conversion's Convention. I have another, more thoroughly documented, set of notes but can't locate them right now. Had them a few weeks ago and recognizing their value put them in the proverbial safe place. These notes are from about 10 years ago. New data may be available. Adopting the comments of an earlier thread, the gen box is made of typically 3/4 plywood and lined with 18 ga sheet metal. Aluminum is insufficient for a firewall. I haven't considered an additional fire barrier, like drywall or other material and open this issue for discussion by the BB. Dick's experience, very summarized, explains that the genset radiator fan is the largest single source of noise (assuming muffled exhaust) He recommends remoting the radiator using 1-1/4 Cu pipe. The remote radiator is cooled by a 2100 cfm squirrel cage fan for a 10KW sized unit. The genset compartment takes a 600 cfm squirrel cage fan for units up to 15KW. My other notes (from a later lecture) break down fan sizes further between 8KW, 10KW, 12.5KW and 15 KW. I'd contact Wrico for further detail. The genset box is lined with A/C duct board. The inlet and outlet are reversing channels a minimum of 144 sq.in. cross section. This is like a rat's maze. For instance, the air enters from the bottom, either by side inlet inside the bay or from below the coach, rises the full height of the genset, makes a u-turn, goes back to the floor of the bay then sideways through the opening into the genset box. All turns must follow the 144 sq. in. cross section "rule" the same thing on exit. The mazes are also lined with duct board. Sound is linear and doesn't like to go around corners. Vibration isolation (conduction) is another issue. The airbags are good vibration insulators but I've always heard of problems keeping them in "air" and this is made difficult by restricting motion so that the bags aren't torn due to sideways motion during braking forces. Securing the genset adequately to protect the airbags frequently results in something coming in contact and conducting noise. Most gensets are mounted on four rubber biscuits in a single plane on the floor of the bay. This is the standard setup, but not the best. The next best "simple" setup would be 2 layers of stacked (4) biscuits clocked 45 deg from eachother. I'd recommend that the bottom set be spread farther to avoid tipping. There is a sophisticated means of optimizing the vibration dampening. It requires a special measurment jig. I'll be building one of these measurement jig setups in the near future. I don't know if it's worth the trouble at this time and it requires an experienced machinist to achieve the desired result. But I'll be able to take sophisticated measurements with special vibration testing equipment at a laboratory. I'll get good before and after data and let the BB know the result. Finally, the exhaust pipe transitions the box with flexible exhaust tubing. Use a muffler consistent with your engine, diesels have a different frequency or "note" and the internals are different from gas mufflers. You can "google" for mufflers and get some pretty interesting data, if you've a mind. The above, properly followed, results in a pretty quiet genset installation. Dick took us to two coaches after the seminar with his units. Neither had a full blown "Wrico" installation but both were very reasonable, noise wise. Your RV park neighbor would have to be pretty picky to give you any guff about those units. Hope this Summary Helps Marc Bourget | ||
| Ed Roelle
Rating: N/A |
I cannot feel vibration in the coach, so I think I was lucky. I mounted the genset on 4 Harbor Freight tires. This allows me to roll-out the genset on a simple track to change oil etc. The genset is installed in a box, with ducing similarto what Marc described (very quiet). There is carpet underlayment (light duty foam - many sq.inches) between the box and the bus bay floor. Ed Roelle Flint, MI | ||
| Chris 85 RTS
Rating: N/A |
I like this tires idea! Best I've heard yet. You could effectly box the tires, then have a simple bolt on extenstion rail to roll the genset out over the side. No heavy duty slides. Pretty good idea. | ||
| david anderson (Davidanderson)
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Yes Ed, I think the tire idea is brilliant and way less cost than a heavy duty slide, and less weight too. You ought to publish your design. Thanks for sharing it with us. David Anderson | ||
| Don/TX
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I did the Harbor Freight tire roll out thing too, had a channel frame to hook on to roll it out for service. Box was lined with the lead/fiberglass stuff, soundown. I was never completely satisfied with mine, the exhaust was pointed downwards 45 degrees, and reflected noise and vibration from the pavement back into the coach, not the way to do it, I think that an exhaust exit to the side if preferable. To silence the intake, the intake air was also baffled, a four cyl diesel intake can make a lot of the racket. I used a 120v squirrel cage blower for cooling the radiator, which was mounted in a separate box by itself, with a scoop to add extra air when cruising. I had the capability of also insulating the compartment of the bus the genset was mounted in, but never got around to it. | ||
| R.C.Bishop
Rating: N/A |
Ed....Don....got any pics you could send on email? Thanx. RCB '64 Crown Supercoach | ||
| James Stacy (Jimstacy)
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Surprised no one mentioned running the exhaust up through the roof. If you have a low genset exhaust you might as well let it make noise, at least your neighbor will know when you are poisoning him. Least problem is a permanent pipe through the roof. (We ran the pipe up through a section of double wall class B flue pipe with a flapper on the top to keep out rain.) Next best is a portable pipe you can hook up when parked and remove before travel. Early in the planning stage is when you need to address this problem, before your neighbor brings it to your attention. Jim Stacy | ||
| H3 (Ace)
Rating: N/A |
The portable pipe is I think mandatory at rallies! at least it was when I attended my first one in Arcadia. Try and find one on a holiday weekend. NOPE! Opted for a piece of down spout from local Scotty's home improvement! Looked bad but worked! Got us and our bussin neighbors thru the weekend and we are still friends today!  Ace | ||
| Nick Morris (Nick3751)
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What about running it back to the bus exhaust? You'd have to put some sort of check valve to stop engine exhaust from comming back to the genset and it would be as far away from anyone comming out the back of the coach as it would up in the air wouldn't it? | ||
| Don/TX
Rating: N/A |
R.C. Bishop, here is a link to some pictures, there are 95 total photos, but a half dozen with genset photos and plans. http://share.shutterfly.com/osi.jsp?i=EegMWLJuzaMmKn | ||
| James Stacy (Jimstacy)
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Nick, Do you have a high exhaust for your drive engine? Fairly common in recent transits but rare in intercity coaches. I don't see much point in running the gen set exhaust back to a low drive engine exhaust. If you want it in the rear just run the pipe out to the bumper. Not a whole lot better than out the side; you really want it up. Jim Stacy | ||
| Richard Bowyer (Drivingmisslazy)
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Many moons ago there were discussions about this, and IIRC, the general consensus was that it was not a good idea to plumb into the main engines exhaust system. The best solution was to run the genset's exhaust vertical thru a closet of whatever to exit out the roof. The next best was , as Ace recommends, is the portable pipe that you can hook up when at a rally or other location where the exhaust fumes would bother a fellow camper. These units are commercially available and cost about $200 I think. BTW, I happen to have one with a nice vinyl carrying case that I would consider parting with since DML is long gone. Richard | ||
| H3 (Ace)
Rating: N/A |
A mast from radio shack works great, cheaply priced but high in quality. The sections fit nicely together and it appears to have a coating that hasn't burned any on mine yet. I DID have to mfgr a curved section out of SS to go from horizontal tail pipe to a vertical. On that curved piece I welded a tab with a hole in it so I can quickly bolt on a stabilizer leg that sticks down in the ground! Ace |