Generator mounting

[eggman]

Looking at mounting the generator under the bus in a cage type frame. Current plans are to weld/bolt uprights forward, inboard, and aft of the generator and use bolts on the lower supporting frame work to facilitate easier removal for possible repair. The way I have it figured all frame work should be 1" square x 1/8" wall tubing. Along with 2" of insulating foam board and 1/2" or 3/4" plywood backing it along the 1" x 1" tubing.

Does this souund like it will work?

The generator is an older early 70's model 4K Onan. Weight is HEAVY!! My guess is around 175 to 200#.

[eggman]

Is that 1" or 1 1/2" tubing? Did you use any insulation around the genny box? And the $1 question, how loud is it on the inside of the bus?

Thanks

[the_experience03]

Is this a liquid or air cooled genset? Liquid wouldn't be bad because you could remotely mount the radiator from the box. Heck...you could probably even tie it in with the heaters in the bus if you really wanted to. If it is air cooled, a sealed insulated box might not be the best bet for obvious reasons although some ducting with electric fans might alleviate the cooling issue while still allowing it to be housed in that box.

[Steve]

If I were building one I would make one like this one. That compartment on the right is where the generator sits and you can see on half of the door an electric radiator fan is mounted to blow the hot air out.

[eggman]

Its an air cooled Onan genny. According to Onan, the only incoming air that is required is an 8 x 12 opening from the outside of the box, along with a discharge opening the size of the "vacuum" chute. Any thing larger would definately be a benefit to the cooling airflow. Also any thing that is combustable has to be at least 6" away from the exhaust system inside.

So, it looks like I'll be about 8" from the exhaust tubing on the front side, about 4" from the top, and about 4" from the rear. Also will be about 4" all the way around the bottom of the genny mounting plate for additional air to draw from. Lining the inside will be 2" foam board and probably a sheet of aluminum instead of the 3/4" plywood. Although I do believe the aluminum will create a bit of an echo chamber. Only time will tell.

Arent the newer style of gennies covered with a plastic box?

Steve, mine already blows the heated cooling air out the bottom of the enclosure. I may be worng here, but wouldnt an extra fan blowing out create a problem with intake and cooling air?

[Steve]

Originally Posted by eggman

Steve, mine already blows the heated cooling air out the bottom of the enclosure.

I don't know what you mean by that? Your gennie has a fan on it? Or you have already built the compartment onto the bus and it has a fan on the bottom?

If you have a fan on your gennie already I would mount the gennie over a grate so it can just blow out of the compartment on it's own and put another screen in the door to allow air in.

Originally Posted by eggman

but wouldnt an extra fan blowing out create a problem with intake and cooling air?

In the I posted as much air as is being blown out is also coming in the second screen letting in fresh air for the engine and circulating air for cooling. To make it work even better you could have the fan on one side and the inlet screen on the opposite side of the box. Maybe kitty-corner them if you have a long enough box.

[eggman]

Steve, this is what the front of my generator looks like. It has a "vacu-flo" system for cooling.



During the last ice storm that we lost power, the air coming out de-iced my walkway in front of the door. Then I moved it back out of the way so we would have more room at the door way.

[eggman]

Thanks for every ones help. Looks like I will be going with 1" x 1/8" wall square tubing. Mounted to the bus body with 3/8" bolts.

[eggman]

Update: Bought steel on Wednesday, 2 sticks of 1" x 1/8" wall square tubing @ 24 feet long. Started cutting and welding yesterday and last night. About 9:30, 30 minutes after the closest Sears store closed, I run out of wire Go Figure. I had the top rack and the bottom welded, was getting ready to weld them together and set the genny in. Oh well. That'll teach me to look at the wire before I start a large project.

[captainkf]

You may want to consider large rubber gromets or washers to mount between the frame of the bus and the frame of the generator box. If you bolt the boxes together and have the rubber washers on top of the bus frame the weight of the geni box will rest on the rubber. Yes the box will move slightly with the bus, but the vibration from the geni in the bus should be much lessend than welding or bolting them together.

-Richard

[eggman]

My thoughts exactly. I have a couple of ole "new" hockey pucks that are an inch thick. I am currently thinking about cutting them in half and using them between the frame and the bus floor supports.

Picked up my wire this afternoon and getting ready to trial fit the entire frame under the bus. Have to make sure all the holes line up

[the_experience03]

Are hockey pucks going to be soft enough? I know an awful lot of cheap guys out there that have made some scary scary body lifts for their trucks ouf ot hockey pucks. Heck...I even saw one in high school made out of boat trailer rollers. I know my hardware store actually sells isolation pucks made of a softer (not by much) rubber.

[eggman]

I dont know if they will be soft enough now that you mention it. Definately bears thinking about it. I have a bit of body manipulation in order to get it fully into place. I did find out that towards the front of between the wheels is about 25 1/2" whereas my genny cage is 26". Thankfully, back in front of the rear wheels is about 26 1/2". So it slides in with little room to spare.

However, I am one of those with the "hockey puck" lift on my 4x4. There are alot of those that will find fault with that type of lift, so be it. Its been about 6 years since I put the 2" puck lift on my scout and I have had no issues with it. It is checked prior to going and after coming back. This summer I plan on a body swap and will be changing them out at that time for new ones. Mine have a piece of steel tubing about 1 5/8" long inside between the bolt shank and the hole in the puck so to give it a bit of room to move and all of the bolts were upgraded from the 7/16" grade 2 that came on it to 1/2" grade 5 . Others in my club will tell you that I wheel mine pretty hard and have broke plenty of other stuff, but never a hockey puck nor a body mount. Not saying the body will stay on forever, due to the "rust" issue that most scouts have.

[the_experience03]

2 inches is reasonable. I'fe seen quite a few FJ-40's out there with hockey puck body mount bushings just because until recently the OEM replacements were expensive and hard to come by. What I'm talking about is a stack of 8 pucks. A 6 inch body lift is a scary thing! The boat roller lift was even worse. He used rebar to extend his shifters. I have a body lift as well . It;s a 3 inch Performance Accesories lift that I could get cheaper than hocket pucks. I needed it back when I had IFS o clear my 34's. Now I still have it even with the solid axle swap to get me some better firewall clearance. Even with my front axle pulled forward, with the amount of wheel travel I have, the close proximity of the firewall on Toyota trucks makes it an issue at full stuff with the wheels turned. Being 6'5" I can't afford to modify the firewall for clearance like some guys do. Not if I want to fit my left leg in the truck anyway.

How about a set of trailer leaf spring bushings. Most I have seen are two piece so a pair of them would give you 4 mounts. They're soft, strong, and cheap.

[eggman]

6' 5" in a Toyota truck? Thats alot of guy in a little truck. 6" body lift or a stack of 8 pucks is way too scaryI did the 2" at first to give a bit more clearance on some 33's that I ran for a while. then went to full size axles and 35's, now I have added 36's for the final tire size. Flexes pretty good, takes about 35" on one tire before it starts to lift another one. Lockers at both ends takes care of the traction issues.

For now, I went ahead and bolted the genny cage directly to the bottom of the bus. Hopefully we can test it out by the beginning of the week to see how much vibration is transmitted from the cage to the bus. Just have to figure out the fuel tank mounting location and bring the main wire through the floor.

[lapeer20m]

Originally Posted by eggman

However, I am one of those with the "hockey puck" lift on my 4x4.

is there any other type of body lift? I thought hockey pucks were the standard....at least for us northern folks.

[the_experience03]

Minnesota isn't north anymore? Last I checked we were the northernmost of the lower 48. We just do things differently here.

I don't know if you will have the same facilities around you or not, but in town we actually have two conveyor belt companies (lots of iron mines=lots of conveyor belts). I've raided their dumpsters before (with permission) to get rubber scraps for various purposes. The rubber is tough, but soft and pliable. That might be just the ticket. A stop by the salvage yard might yield to an old snowmobile track. These are likewise soft, but tough. They might give you just what you need.

[frank-id]

For now, I am using a 7KW Kohler in my RV. I'm hoping to find a Diesel gen set. These units are very spendy. My gen mounting is at...
http://www.bustropolis.com/forum/viewtopic.html?t=367
Frank

[Ryan Grimm]

Eggman, I'd use rigid fibreglas sheet in the gennie compartment instead of the foamboard....foamboard can melt/burn!

You should be able to get rigid fibreglas insulation in a variety of thicknesses/sizes from an insulation supply company....this is similar to the rigid fibreglas insulation used for high-temperature (steam) pipe coverings.