Building the 102DL3 (continuation of "Bumper" thread)

[Jim Blackwood]

Thanks guys, all of this advice is really helpful and I mean that sincerely.

Yes, I see now that the HVAC would have to be between the 2nd and 3rd bay from the front. Just going from photos until later this week.

I do not plan to have a very large kitchen counter, so I hope to get by without a whole lot of weight there. If I can shave a half inch off the thickness I'll do that, provided it doesn't make it too weak around the sink. For flooring I plan to look and see what sort of new materials are available. I understand there are some pretty good synthetic floor coverings that look good, wear well, are waterproof and provide some cushion. Hopefully that can go over the existing floor without much trouble (some leveling at the old floor tracks I expect) and at a reasonable cost. That shouldn't add all that much weight. Provided I find something I like I may use it throughout. No claw foot bathtub. Fiberglass will be just fine. The bathroom counter doesn't need to be anything special, the main reason for granite in the kitchen is because you never need to worry about setting a hot skillet on it. Seen way too many countertops ruined that way.

I do get the point about the weights adding up. It's the opposite of adding lightness in car building, every gram does count. But, 3 tons is a LOT of weight, and yes, there's a lot of stuff to go in. Still, I don't think I really need to skimp on the construction to keep the weight down, just try to use light materials where it makes sense to do so.

Now about that front axle loading, it must be rather critical because I'm hearing two perspectives there. One, load the heavier weights rearward to keep from overloading, and Two, be sure to get enough weight on the front axle to avoid skidding under slippery conditions.

In your experienced opinions then, provided your front bay is open for personal gear and possibly some of the second bay (driver's side), when you pack up to head out how much weight do you think you add to those areas? Some sort of estimate would help me approximate the front tire loading when ready to roll.

As for tools, yes I will be carrying some weight there. Blocking and such will be downstairs but most of the hand tools and such will be in the back room over the tag axle. That room will gain weight over time, but exactly how much is hard to say. More of that weight will be on the driver's side than on the passenger's. I'm not sure that properly offsets the weight of the granite countertop and stove (refer is opposite) but I figure if I avoid anything that will obviously unbalance the bus it should be OK. I mean, did any of you drivers ever have to tell people to move to the other side of the bus? I sometimes had to do that when I guided whitewater rafts but that usually had more to do with paddling strength than weight.

Both of my waste tanks will be full height, no reason not to. At least in the current plan, which of course could change. 17" wide and presently I'm thinking that the 70 gal or so capacity I'd get by making them each half the width of the water tank is going to be adequate. Easy to dispose of gray water and that much black water is probably more than I want to carry around for any length of time anyway. That's a lot of toilet usage. And it gives me about 30" of overall full width depth in the bay. Some of which will be taken up with plumbing of course. I'll think about the tank for drinking water, it's a decent suggestion and not too hard to add, but it's a lower priority so I'll see how things look once the other bits are in place. I think I could add close to 40 gallons rather easily, but I'll see how the weight goes.

Thanks for the tip about the electrical by the way.

And finally, where are these MCI bus conversion groups you recommend? If it's Facebook, I sort of have a problem with all the effort required to sift through the endless socializing in attempts to find one or two lonely nuggets of relevant information. You can question my competence to do this job and probably you should. But likewise I shouldn't have to keep repeating my past experience and qualifications. I'm not some damned dummy who's never done anything like this before. OTOH, there most certainly is MCI specific information that I do not have and even more particularly 102DL info, and I am certainly grateful for any of that which come my way from any source. Delivery is just days away now, perhaps as soon as midweek so I feel like this sort of advance planning has been extremely helpful.

Jim

[windtrader]

Make sure to consider the fall for the lines feeding gray and black tanks. You'll likely to use tanks not as tall as the bay unless you run the plumbing above the floor.

Jim, you seem totally competent to me in undertaking this sort or project. My only point is to simply piggyback on the existing work and body of knowledge that precedes you. None of this is rocket science and nothing that has been chewed over for decades. It seems to me it would be quite acceptable to develop a list of best practices, design considerations, etc. that would likely get 90% of the coach to meet your needs, leaving the 10% for your unique requirements and desires. I'm sure your end result will work fine for your desired requirements and I am very interested to follow along your journey. Who knows, it might inspire me to want to DIY convert one of these MCI coming out of service. They are so cheap, you can buy two, keep one for spares.

My distaste for FB is substantial; I rarely use the word hate but FB comes close for a variety of reasons. FMCA has some groups that may be useful. There is a fairly large group of GM busnuts that seem still intact. Maybe an MCI focused group exists. Like anything and everything done on the internet o.ne must do quite a bit of heavy filtering to find the bits that apply to your inquiry, still worth in my opinion, one good tip can save a lot of angst, wasted time, labor, and resources avoiding some error in design or build.

[Jim Blackwood]

I've seen 1/4" per ft as a recommended slope for drain lines, and none of my lines are going to be longer than 4 ft if my layout holds. The toilet will be a direct drop. Final tank dimensions will take that into account, as will tank positioning so far as possible.

I don't mind doing the weight calculations to locate the tanks. Each of these is going to use different tanks and different volumes. Unless someone set up to make tanks specifically for the DL I can't see that changing. Plus, it looks to me like the DL is yet to become a big player in bus conversions. It's the new kid in town and chances are pretty good it's going to take off but we're only seeing the beginnings of that, so I don't really think there are that many of them out there yet. I've been through a similar scenario with MGB engine conversions, you hit a critical mass and then established methods begin to appear. I'm just not sure we're there yet.

Jim

[buswarrior]

Remember, your plumbing gets to sit on an angle when parked someplace less than level.

House plumbing 1/4 per foot won't drain in lots of parking situations.

Steeper runs, and you'll never think about it again.

happy coaching!
buswarrior

[RJ]

Jim -

Some thoughts and info for you:

Our recently sold MCI MC-5C (35') had two water tanks in the rear bay.  The grey/black tank was (20" x 21"x 54" = 98.5g) mounted E/W across the back of the bay. Dump valve for the tank was thru the floor on the driver's side, per code.  Toilet dropped straight into the tank on the passenger side, as were the kitchen and bath drain lines. The tank vent went out the rear bulkhead and exhausted in front of the RR dual.  The freshwater tank was (20"x 32"x 36" = 100g) mounted N/S in the center of the bay in front of the grey/black, with the fill coming in the top on the passenger side, with an adjacent 1/2" overflow discharge hose going down that bay's front wall thru a hole in the floor. We could go 7 - 10 days easily without having to dump by just being careful with our water usage.

On the driver's side, between the freshwater tank and the bay door, was the 8kW PowerTech diesel genset, inside it's own soundbox, mounted closer to the front of the bay's wall.  At the rear of the genset was the dump valve for the grey/black tank, exiting out the floor of the bay.  The back wall of this bay also had the auto transfer switch and the marine shore power connections.

On the passenger side, in front of the grey/black tank, sat the 11g SeaLand electric hot water heater.  This unit has a heat exchanger inside, which was tied into the coach's HVAC hot water line.  Thus going down the road, the engine heated the domestic water, and we'd only have to switch it on if we were parked for several days. The water pump was mounted vertically high on the front wall of this bay, feeding an accumulator tank that hung from the ceiling above the hot water heater.  All the plumbing was also on the ceiling.  The way this bay was laid out, I could actually stack eight of those square milk cartons with "stuff", and still have room for my 20-ton air-over-hydraulic jack.

The front bay (this model only has two) was completely open side-to-side, except for the house battery bank in the front portion of the bay. This housed two 8D deep cycles for the house, a Group 31 start battery for the genset, an Iota "smart" charger, a Vanner equalizer and the coach and house battery cut-off switches.  The coach A/C portion of the HVAC system was inoperable, but the heating system worked - thankfully! (HINT: Don't disable yours!) All of the A/C components were still in the condenser compartment behind the LF wheel, but I had planned on removing all of that equipment and moving the house batteries into that location in order to free up some space in the front bay.  Sold the coach before that happened, tho. . .

Angola Coach did the conversion on a brand new shell, and ALL of the cabinetry upstairs was built using 3/4" marine plywood, with a wooden laminate on top for looks.  Corian was used for the counter tops - kitchen, bath and dining room table. Drawers were built with 1/2" marine plywood, all with dovetail joints.  The coach was a '78, and not a squeak or rattle still.  Those on this board who have seen "Tortoise" can attest to the quality construction Angola put into their work.

Now, to answer your question, how much did all this weigh?  Well, we went across a local grain scale as we were leaving to go south for the winter, full of water and fuel (144g), plus loaded with all our "stuff" for five months on the road.  We tipped the scales right at 28,000 lbs - 10,450 on the front axle, 17,550 on the rear.  Coach has a 12,000 lb front axle limit, and a 20,000 lb rear.  Thus, fully loaded, still 4,000 lbs under our maximum GVW.

The 1992 40-foot Prevost we recently picked up is a completely different animal.  Converted on a new shell by Vantarè, I'm still trying to figure out all the thinking behind the build.  I do know that in the rear (4th) bay there is a 90g grey tank, a 60g black tank, the 150g fresh water tank, four 8D deep cycle house batteries (they're HEAVY!), two inverters, the auto transfer switch and a bunch of other electrics that I haven't figured out yet. I can tell you right now that after having the single grey/black tank on the MCI, having that split into two tanks is a big PITA to dump and rinse.  Yes, I can dump the grey into the black, and yes, I can dump the grey on the ground if I want, but I don't like that when trying to rinse the black with the grey, as the tanks equalize, sewage from the black can flow back into the grey.  Not smart!  IF I was building a two-tank system from scratch, I'd put the grey on top of the black with two dump valves - one to dump in the normal manner in a "Y" configuration with the black, and one on the passenger side dumping straight into the black for rinsing purposes.  Or simply use a single tank for both.

In the 3rd bay, passenger side has the AquaHot system, center in a N/S position is the 160g fuel tank, the driver's side has the shore connections (which go out thru the floor) and genset radiator/cooling blower in it's own soundbox.  The 2nd bay, passenger side, has an undercounter mini-fridge, a CruiseAire unit and storage.  Driver's side has the 15kW Martin genset in a sound box with two squirrel cage blowers for ventilation. The 1st (front) bay is completely open for storage, including a 24"x 48" Joey bed slide.

The inside is similar to the Angola in that it's all built with 3/4" marine plywood.  Vantarè was started by a yacht builder, so there's lots of experience in the build - you know, "how to put a quart into a pint bottle" type of storage everywhere. Marble floors in the galley and bath, granite counter tops in both, a 20cuft residential fridge, Splendide washer dryer, two complete entertainment centers front and rear, etc., all add to the weight of the rig.

When we first picked it up, and after topping off the 160g fuel tank, we ran it across a CAT scale in Chandler, AZ.  We had no idea how much fresh water was on board, nor what, if anything, was in the two holding tanks.  Rig weighed 40,120 lbs total, with 12,560 on the front axle, 18,460 on the drive, and 9100 on the tags.  We're getting ready to head south for the winter, so we'll run it across the scales again with all our "stuff" on board to see how things have changed (and to adjust the tire pressures appropriately for the load.)  For reference, the numbers on the Prevost's builder's plaque are GVWR 42,000, front 13,000, drive 22,000 and 10,000 on the tag with 12R22.5 tires on 8.25" rims.  It's a LOT heavier than the MCI, but it's also five feet longer, six inches wider and 18" taller, too.  Oh, and yes, I'm very much aware that I'm close to the limit on the front axle, so will be paying close attention to that as we go.

I know I've written almost a "senior paper" here, but wanted to share with you some real-world numbers and experience that hopefully you can put to good use - recognizing that you've got one more bay and five more feet to work with.

FWIW & HTH. . .



PS: If you crunch the numbers, the MCI's weight distribution is almost identical to a '70's-era 911 Porsche, percentage wise! Sadly, it didn't have the power/weight ratio!

[luvrbus]

They are getting the buses up into the 60,000 GVW range now with just tires and adding more weight to the tag axle,the tag axles are starting to carry about the same weight as the front axle.I always wondered why the tag was so light on the older buses 

[Jim Blackwood]

That was some very good information and gives a real world feel for how some typical loadings will work. I'll have to check on the availability and pricing of the marine plywood, that'd be a cut above the typical oak faced plywood. Better in the long run I'm sure, probably either could be made to work. I'm also a big fan of solid hardwood edging on the cut edges of the plywood. There is a trim piece about 3/8" thick with two rounded corners that works very well to glue and nail on and it can be formed around large radius curves and some smaller bends if it is steamed.

Regarding dumping the gray water through the black water tank, I feel if that is to be done, there are a couple things that might help. First, size the coupling line smaller than the outlet to reduce the amount of "equalizing" that occurs when the coupling valve is opened (only after the black water is dumped of course), and secondly, run a second dump line from the gray tank. In my case this would be a line from the other end of the gray tank with a "U" and running under the edge of the water tank to "T" or "Y" into the dump line. (my water tank has a slanted bottom so there is room to do that) Then finally, depending on how the system acts, after dumping the black, open the connecting valve and either run it some and shut it off and finish dumping through the second line, or open both dump lines. I'll be looking at sizing on these pretty soon. As I recall 3" is pretty common but 4" and 2" are also available. If  4" is used on the black water then a 3" coupling line and a 3" dump on the gray should do the job I think. So with the black tank emptied and the gray tank near full nothing is going to back up into the gray tank before it is half emptied at least. In that time the black tank should be pretty well flushed. But, the connecting valve could be closed at that point to be safe.

Are you guys using the typical bolt-and-indicator light setup to show levels or something else like a sight tube? I'm thinking the bolts are the easiest probably. I'll have to have insulators of course. One wrinkle I just thought of would be to use small expandable stoppers, that way they are easy to replace if the seal rots. Might even get by with just using a holesaw, stick in the stopper, put a wire under the nut and clamp it down. I'll look into that.

Jim

[luvrbus]

I never worry much about cleaning the black tank both our RV's have built in sprayers,I just hook the water supply up and turn it on till the water is clear

[sledhead]

when I empty my tanks and there is some fresh water in the water tank I use the sprayer for the black tank to add lots of water . then I drain the black tank . then I empty the grey tank to clean the valves and drain the line . I have a power valve that I can empty the grey tank from the drivers seat if ever needed . not that I would ever do that when I am driving . dam tailgaters

dave

[sledhead]

double post
oops crap !


dave

[Jim Blackwood]

I guess y'all heard about that guy who got caught dumping his tanks across a cheese grater bridge and hit the pleasure boaters with it? I can sympathize with 'em, that's nasty. No remote dump for this rig. I want to know exactly where that $#!% is going.

One step closer, all the purchasing details are completed, simply waiting on delivery.

Jim

[Jim Blackwood]

(Driver for the Steve Miller Band, incident occurred in Chicago, resulted in a civil suit. So, don't do that, it made people sick.)

But on that topic, someone mentioned venting the waste tanks into the wheelwells and I find that prospect intriguing. Well first I naturally have to ask, does it ever smell a bit when you walk around the coach? But once you get past that the idea seems to have some real merit because wheelwells are often a low pressure area, meaning it has at least the potential to draw a partial vacuum on the tanks going down the road. That could be tested with a manometer.

But how do you deal with the splash? I mean you can't just run directly back with it, the slosh in the tanks would have you dumping on the road. I suppose you could route the tube in a square circle around and above the tank, that might do it.

I'll admit, I'm not at all familiar with how busnuts handle this. I think I saw one reference to running it up somewhere inside the rear cap, maybe up by the radiator fans? That seems like it could be a practical solution. What do most of you guys do about this?

Then there's the whole question about the pressure differential going down the road. There was a discussion about this, how the pressure inside the bus tends to be less than outside so that when you flush it stinks up the inside of the bus. I've heard people complain about this on commercial bus rides. So I just wonder if it would be feasible to maybe attach the vent line to the radiator fan shroud? The idea being to have the fan try to draw air out of the waste tanks any time the engine is running. Is there any chance that might work?

Jim

[richard5933]

We've got the original system as installed by Custom Coach. Our venting consists of a length of 1/2 OD vinyl tubing run from the top of the tanks and back down through the floor of the bay immediately next to the tanks.

There has never been any splashing of the contents from the tanks out the vents. But, we never let the contents get within a few inches of the top since it would also bring smell into the bus and possible sloshing into the bottom of the toilet.

What's clear from our set up is a few things: The minimal venting we have serves one purpose - it allows air in/out of the tank as necessary to allow for the change in fluid level. That said, when we dump the waste tank it will gurgle the water in the P-traps. Also clear is that this type of venting does not keep smells from coming out of the toilet when it is used, especially if used while on the road.

If you read through the FMCA forum for threads about venting, you'll see that this is an issue for nearly every type of motor home and RV. From my reading, the best method is to use a 2"+ PVC pipe going straight up through the roof, capped with a gadget that causes a negative pressure from the slightest breeze. This setup seems to reduce odors in the coach regardless of whether the coach is in motion or parked.

This is our second Custom Coach conversion, and I'd say that the venting is one area where they missed big time. If I had an easy way to do so i'd run a vent from our waste tank directly through the roof before our next trip. Any method that you're considering which doesn't vent up and out will likely have issues with odor inside the coach.

[buswarrior]

Stink comes from poor venting.

Lack of oxygen to the correct bacteria let's the smelly bacteria rule the tank. With enough air, a holding tank smells much better, the stink doesn't get generated in the first place.

Two vents, allowing cross flow, and you'll not waste your money adding perfume to the tanks again.

If your coach gives off nasty odours, nobody wants to be your friend.

The boat peeps have a guru on sanitation.

Peggy Hall writes a great book https://www.amazon.com/Get-Boat-Odors-Peggie-Hall/dp/1892399156

It is not unheard of to have two 1.5" vents out either side of a boat to accomplish good aeration.

Happy coaching!
Buswarrior

[Jim Blackwood]

OK, well I can see where practicality might impact the theoretical here. Makes me wonder how hard it would be to run a couple of 2" lines, one down either side of the bus up and into the fan shroud. In my case with the two waste tanks running near full width I could just tie the tops together in the middle. That way any sloshing would tend to draw in fresh air maybe.

Are you saying that actually circulating air through the tank would make it stink less? Seems a little counterintuitive, but maybe only hook one of those lines to the fan shroud and go through the roof with one of those FMCA doohickeys on the other?

Probably would be better to put the two lines on the black tank and run a smaller single vent line for the gray tank and tie it in about half way up.

Jim