| Author | Message | ||
| Esther (65.142.73.225)
Rating: N/A |
It's getting close! In one month we will be home, and getting our MC-9 to convert. One of the first things I'll be doing ( after we strip out the seats, etc.) is installing two roof airs. The GMC 4108 we have now, the roof airs were already installed when we bought it, they are off-set, I guess so they did not have to cut through the center beam. Well, it a was a converters nightmare trying to work around! I am assuming the MC-9 has a center beam. I have noticed 99.9% of all the conversions out there have there A/Cs installed down the center, so it must be ok. Is it? So, the question is, should I build a wood frame around the hole? Or, just leave the hole as is? What should I do? Thanks. | ||
| jmaxwell (66.42.92.1) Rating: N/A |
Yes, there is a center beam. You might consider using the two roof hatch holes and framing them in to 14 x 14 for the AC's. There are plenty of windows to exit in emergency. | ||
| SLO (Slo) (24.205.227.122)
Rating: N/A |
I have wondered also about the center strut. I had planned to offset my rooftops to the starbord side to avoid the roof framing. Also, to have them offset fits my floor plan since it would center them in the living area. The issue will be leveling them. I plan to build the opening using sheet metal since I have a break at my disposal. Wood is not in the plan, even as a filler. I found the photos of my exposed roof, and will Email you a couple that show the most of the framework, as it is identical on the MC9 to my knowledge anyway. Side note, yesterday I went to remove the front door, so I could insert the refer. Easy enough, I have the exploded view of this area.....no problem, right?......Wrong. Today will be day 2 of attempting to remove the door, and very likely will involve drilling fasteners and replacing them to remount the door. For those of you that plan on converting a unit on a time line, allow lots of time for "unforseen circumstances".....nuff said. SLO | ||
| Buswarrior (Buswarrior) (64.229.209.74)
Rating: N/A |
I'd throw in 2 cautions about plugging your roof hatches full of air conditioners. Roof hatches are great things to have on a cooler day, when there is no need to run those awful noisemakers and you want a little air. It is very nice to open them and have screens made up to get silent, bug free airflow. Roof hatches original, and I'd say, ongoing purpose are for using when you have rolled it over in the ditch. Picture your coach lying on it's side, and try to figure out how you and your loved ones are going to open those heavy side windows upward, 8 feet overhead. Without roof hatches, the only way out will be to walk down the walls and out the windshield, as long as your interior doorways aren't offset too far to the wrong side, and you haven't buried the front of the bus into something too. I'd say cut some new holes and keep your roof hatches, both convenient and safe. happy coaching! buswarrior | ||
| Gary Stadler (Boogiethecat) (68.7.217.217)
Rating: N/A |
I didn't have the center strut problem in my Crown, however the "how to" was about the same, problem wise. I ended up cutting my 15x15 hole in the roofing sheetmetal and then (very carefully) welding a frame made of 1/2 x 1" rectangular steel tubing into the hole, so it sticks up an inch above the roofline. When done I sprayed the welds and the frame with a few heavy coats of zinc-rich galvanizing primer, both inside and out. This makes a very waterproof and extremely strong interface. If you had a structural rib running under it, it wouldn't matter (it would actually help), and now that the frame is there, more structure can be welded to it from below if necessary. The fact that it's top surface sticks up an inch above the roofline (thus leaving a good gap between the bottom of the AC unit and the roof below it) makes it almost impossible for water to find it's way in, and it also discourages pooling and moisture buildup under the AC that I have seen totally ruin many RV roofs. The rectangular tubing gives a very flat, strong surface to mount the AC unit to. Just a though and a different approach... Cheers Gary | ||
| R.C.Bishop (128.123.221.207)
Rating: N/A |
Gary, am I missing something here? Isn't your roof skin Aluminum? Our Crown has all aluminum skin. Just curious how you welded alum skin to steel tubing. Also do not completely understand the reason for the raise above the top of the roof. My fifthwheel Prowler has never had an A/C leak problem (1981 model) but I'm willing to learn new things  Don't have any pics of that construction, do you? RCB | ||
| David Anderson (66.90.199.40) Rating: N/A |
I cut the center longeron in my eagle and blocked and welded a metal frame 14"x14" just like the hatches were engineered (except they were 22x22 and had to be reduced to 14x14) You shouldn't lose any structural strength that way. David Anderson | ||
| Gary Stadler (Boogiethecat) (68.7.217.217)
Rating: N/A |
Hmmm RC, I guess I'm the one who missed the obvious, not you !! ...Turns out that way back in '62, my Crown was ordered as a "special" with no back doors, a nasty high ratio on the rear end (5:29 ugh) and the body to be made of all steel. So with exception of the front and rear caps and the actual front panel of the bus, there's not a drop of aluminum anywhere on it!! It has certainly made things like moving the door to the side, paneling in the windows, etc. MUCH easier on me than had the bus been all aluminum!! I have seen A/C's plopped straight on an RV roof (sheet steel roof that is), gather moisture between the AC/roof interface and rot the heck out of both the roof and the bottom of the AC. So I decided to do mine more like a skylight in a house, and raise it up a bit. Structure-wise it's now extremely strong, and there's not a chance of water building up, rusting things, or getting in. Here's a fw photos- I don't have many pre-installation photos so you can't see it all... Here's how I welded in rectangular tubing (grey) to support my interior roof, and make space for the foam insulation. I welded the AC frame down to these supports once it was welded to the roof http://www.heartmagic.com/00CelingRibs.JPG Here's a closeup and a drawing of how the structure goes... http://www.heartmagic.com/00ACinstall.JPG Here's what it looks like from the outside http://www.heartmagic.com/00RoofairOutside.JPG Here's what the insides look like now that it's done. You can see some of the supports (the reddish metal) welded to the grey ribs http://www.heartmagic.com/00RoofairInside.JPG Cheers Gary | ||
| Michael J (Mjryan) (67.41.234.207)
Rating: N/A |
Gary, What is your head room down the middle of your bus after you installed the metal rafters? I like the way you did it. Michael j | ||
| Gary Stadler (Boogiethecat) (68.7.217.217)
Rating: N/A |
I raised the roof of the bus exactly one foot, so headroom after installing the cedar T&G that I used for my ceiling is two inches shy of 7 feet. For you tallies it may not be enough but the wife and I are 5'7 and it seems to us like forever up there!! Here's a couple photos showing the A/C structure just after foaming http://www.heartmagic.com/00RoofFoamed4.JPG and with the cedar installed http://www.heartmagic.com/00CabRoof2.JPG The fluorescent light has since been converted to 12 volt ballasts. I like em a lot. Cheers Gary | ||
| RayC (142.165.222.227)
Rating: N/A |
Just a word of caution, the boards always say frame the hole 14X14 but if you go to the AC manufacturers site as I remember it one says 14 1/4 and another 14 3/8 so check out these sites for the unit you are installing just so you don't have problems later. |