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DWJoyce 08-29-2020 10:58 PM

Nice bus.
Let me get this straight. You spent $3000 for the bus, $3700 for a used engine, and $6200 for new gears? Why not just buy a used Prevost? Those things hardly have any wear on them.

Good luck on your project. Have fun and drive safe.

flattracker 08-29-2020 11:53 PM

When I purchased the new Crown it had an engine that ran perfectly. The failure of the main bearing was a complete surprise to me. By then I had purchased many of the items to be installed, as well as fabrication tools, construction materials, etc. My reasoning was either abandon the project, sell a non-running 34 year old bus, and what to do with all the stuff I bought to do the project, or fix the bus. I chose to fix the bus. The gears were an elective modification to improve the usability of the bus, as it had a usable top speed of 63 mph. I now have a roadworthy Crown that will climb any grade and probably get decent fuel economy. I have looked at auctions for Prevost buses and found them expensive to buy, and usually have high mileage.

Bus'n it 08-30-2020 08:48 PM

Its only money. You did the right thing for your needs. I would have done the same. This is why we choose the rigs we choose. If my bus blew its top, well, i would most likely rebuild the engine to a higher spec. Its what we do! Live life. Searching for another is not as fun as it sounds to be. "Run what ya brung!"

Iceni John 08-30-2020 09:13 PM

Regarding solar panel angles for maximum solar harvest, these two websites have useful information:
Optimum Tilt of Solar Panels This is why I have tiltable panels.
Solar Irradiance - calculate the solar energy available on your site You can look up your own home town, or somewhere close to it.

I was also trying to find the NREL's information on insolation values (W/m2) at selected cities around the USA, and how much energy could be expected to be harvested throughout the year at each location depending on whether the panels are fixed or are tiltable in 1-axis or 2-axes. It looks like that site has gone away, but if you can still find it you'll know exactly how much power your own array should produce throughout the year.

Because Bly OR is many hundreds of miles north of sunny Orange County SoCal where I am, it's especially important to design your PV system to harvest as much energy as possible, bearing in mind the much lower sun and shorter daylight hours in the OR winters compared to here.


Iceni John 08-30-2020 09:34 PM

Found it!
Scroll down to page 181 for Medford OR, the closest I could find to your location.


Tejon7 08-31-2020 12:38 AM

Your planning and forethought are inspiring. Bummer about the engine problems, but it sounds like you made the best of it. Having that extra power going up long mountain passes must be awfully nice! I love your bus and I can't wait to read the next chapter in this conversion story. Thanks for sharing.

I feel selfish asking, but... More pictures please! :biggrin:

flattracker 08-31-2020 02:28 AM

The Conversion of my 86 Crown Supercoach
1 Attachment(s)
More pictures are coming!
Thanks for compliments about the bus. My posts will be catching up to the present progress in the next couple days. I hear concern about how much power will be generated from the one Kw array I am installing. I realize that the farther one gets from the equator, the less power can be generated in winter, however it must be a good amount, as there are two large solar plants within one mile of the bus's current location at Bly. The smaller one generates 5 Megawatts and the larger one generates 8 megawatts. Over by the Lake County Airport about 42 miles from Bly is a much much larger plant. I am not too worried about solar generation since I will not be living in the bus, and during the winter I will have more than enough to keep all batteries fully charged.
I also think I did the right thing to repair and upgrade the Crown. Based on my experience of putting over 20,000 miles on my first one, I will enjoy the extra power and highway speed. I believe I could purchase a used factory made motor home for the cost of the Crown and its conversion, I could not match the quality of a Crown Coach for far more cost. An advantage to Skoolies is that ones made after late seventies were made to strict Federal Motor Vehicle Safety Standards (FMVSS) that factory RVs and tour buses were not required to meet. One final point, where else could I ever get the cool lines of a Crown Supercoach? See the remnants of the Crown's original engine.

Native 08-31-2020 03:55 AM

Were you taking it out to the graveyard?

flattracker 08-31-2020 04:02 AM

I have already removed the heads and will be having the sleeves, pistons and rods removed from the block since they are still good, but I planned on scrapping the block since I don't need it. The main bearing is still welded to the crankshaft so it is slated to be yard art. I haven't determined what to do with all the extra parts from the donor engine yet.

flattracker 08-31-2020 04:05 AM

The Conversion of my 86 Crown Supercoach
3 Attachment(s)
In this post I discuss my generator wiring installation along with some illustrations.
In my previous posting I documented that the generator is configured for two legs of 120 VAC/ 240 VAC. To connect this to the RV electrical system I am doing like one would connect to a house, using four wires:

Black - hot 120 VAC
Neutral - for both legs of 120 VAC
Red - hot 120 VAC
Green - Ground

The generator, an Onan 6.5 DKD (6.5 Kw powered by a 3 cylinder Kubota Diesel) is installed in what was the spare tire compartment. It has two 30 Amp legs (even though that equals 7200 watts total Onan rates it at 6500 watts)
To carry 30 amps one needs 10 gauge wire. I went overkill and used 8 gauge wire.
This generator also came with remote operation capability, a feature I want to use. The wrecked motor I removed it from after purchase had a remote start on the instrument panel, but it was just the switch and a light.

Making the remote operation cable:
I studied the manuals for the generator, as well as examined the remote cable that came with the generator, and realized the 9 pin connector on the generator only used 7 of the 9 sockets on its connector. The approximately 5 feet of cable I could extract from the wrecked motor home only used five wires. The cable consisted of the male connector 8 wires, stubbed with the needed ones spliced to wires installed during manufacture of the motor home. I removed all added wires from the stubbed wires, and spliced about 25 feet of new wire to each of the 7 wires actually used. It turns out that oil pressure and coolant temperature gauges are optional on this generator. I wanted both for my installation, so all the wires used are now there.

The installation method:
Between the now generator compartment and the engine compartment is a steel wall, and all wiring to/from the generator has to pass through it. I wanted a way to provide water resistant passage through the bulkhead for the generator's output and controls, so I used outlet boxes made for use outside. These boxes have an opening in the back, ends and sides, and are made to mount to a surface through holes you punch through the casting. I mounted two of these boxes on the firewall in the generator compartment. They can be seen in the attached picture in my posting of the generator install. I used 1/2 " NPT pipe with an adapter to fit the 3/4" hole in the back of the cast outlet box, connected with various conduit components to keep water out (see the picture). The power output wiring from the generator was passed through using 3/4" conduit components (also in the picture) The two conduits pass to the rear of the bus just under the floor, passing through two cross members under the floor, and up through the floor to inside the bus. All total within less than 10" basically inline are three conduits, and one of the Propane lines next to the wall of the bus. (see second picture)
Ten foot lengths of conduit are sufficient to connect at the engine side of the bulkhead to the point where all go through the floor. The through floor location is just before the wheel well. It is a protected location.

The additional hatch:
Because the area to the right of the transmission is the planned location of the holding tank and the propane tank, an additional hatch is necessary for ease of access for installation and usage. I do not want intrusions into the engine compartment and alongside the transmission is unused space. We made an opening through the body siding below the floor the same size and the ones for the engine and the original spare tire compartment. The new hatch is not yet installed but the materials for the new cover are in hand.

The connection for outside power:
I constructed a connector mount to mount underneath the floor adjacent to the second crossmember near the through floor connections. I am using a twist lock 4 pin connector that is standard for 50 Amp service at an RV park. I used 6 gauge wire in a single cable passing through 3/4" NPT pipe. (see third picture) This is the third cable in the row of electrical wiring through the floor.

In the next post I will discuss the fabrication of the holding tank frames and mounts, the installation of the propane tank, and the holding tank. I will also discuss the installation of part of the propane plumbing.

JackE 08-31-2020 06:26 PM


Originally Posted by flattracker (Post 402251)
It was configured with two 120 VAC output circuits, one with a 30 AMP breaker and the other a 20 AMP breaker.
Once my brother and I removed it from the Bounder, and transported it to the bus, we started it up, using a 1 gallon fuel can and a hose. Sure enough it put out the expected voltages, but not in the configuration I wanted, which is 240 VAC, like the power coming into your RV at a park or to your house.
I found the Onan manuals for this generator on-line and through careful analysis of the schematic determined what wires to change and where to. Onan provides the schematic for the 240 VAC configuration but the labeling of the schematic is confusing. A look in the control box helps some by looking on the inside of the cover at the diagrams. A look at the actual wiring is not the clearest way to understand the changes (see picture). Fortunately Onan does label the important wires so that one can figure out which wire is which. After configuring all wiring out and changing the needed wiring (in the process finding a serious factory defect, a wire to one of the circuit breakers not tightened with obvious heat damage), we started up the generator and checked the voltages and all was good.

I'm curious about being able to switch this from a 120 to a 240 application. I have a 6500 watt onan out of a Southwind. It is a 2 cylinder gas variety. Is there a possibility this has the same capability of being switched to a 240V generator? Mine has 2 separate 120 legs and breakers in the generator body that are labeled 15 amps each. I know just enough about electricity to let go when I'm getting shocked.....:nonono: Actually I do understand quite a bit about it, but not enough to know this was even a possibility. I have already mounted the genny under the bus, but since I did that, I decided to buy a 12,000 watt 240V to replace it with. If I can convert this one, I can leave it where it is and can dedicate the new one to running the house during our frequent power outages.

flattracker 08-31-2020 11:33 PM

configuration of 2 cylinder onan gas powered 6.5 Kw generator
You don't state which model of Onan generator so I cannot give the most definitive answer. However for older models of 2 cylinder gas powered generators the following may help:
If you generator has all its covers still installed, there will be a schematic and wiring diagrams found inside the cover. The 5 Kw Onan I have in the collection has four wires labeled M1 through M4 inside the cover. On this generator, there are three possible wiring/voltage output configurations:

A) 240 VAC with neutral - M2, M3 connected together for neutral and ground.
M1 hot 120 VAC to neutral (M2)
M4 hot 120 VAC to neutral (M2)
M1 - M4 240 VAC

B) 240 VAC - M1, M4 connected together
M2, M4 240 VAC M2 is ground

C) 120 VAC - M1, M3 connected
M2, M4 connected
M1, M4 120VAC ground at M2
The 6.5 Kw should be the same if it is of similar vintage. The later Emerald series I have not looked at

84chevyguyid 09-01-2020 01:05 AM

Sweet bus! I attached a really good video about bus insulation techniques that may be of interest.

flattracker 09-01-2020 03:48 AM

thank you for the link. I watched the video.

Native 09-01-2020 04:45 AM

You may be interested in his testamonial on the EHP company website.

JackE 09-01-2020 08:37 AM


Originally Posted by flattracker (Post 403599)
You don't state which model of Onan generator so I cannot give the most definitive answer. However for older models of 2 cylinder gas powered generators the following may help:
If you generator has all its covers still installed, there will be a schematic and wiring diagrams found inside the cover. The 5 Kw Onan I have in the collection has four wires labeled M1 through M4 inside the cover. On this generator, there are three possible wiring/voltage output configurations:

A) 240 VAC with neutral - M2, M3 connected together for neutral and ground.
M1 hot 120 VAC to neutral (M2)
M4 hot 120 VAC to neutral (M2)
M1 - M4 240 VAC

B) 240 VAC - M1, M4 connected together
M2, M4 240 VAC M2 is ground

C) 120 VAC - M1, M3 connected
M2, M4 connected
M1, M4 120VAC ground at M2
The 6.5 Kw should be the same if it is of similar vintage. The later Emerald series I have not looked at

Thank you. At least this gives me somewhere to start looking. I have the Emerald III GenSet. I'll check with Mr. Google and see what I can learn.

flattracker 09-09-2020 05:08 AM

The Conversion of my 86 Crown Supercoach
8 Attachment(s)
In this post I discuss the installation of the propane tank, fabrication of the holding tank mounts, and installation of the holding tank under my 86 Crown.

When I did the conversion of the previous Crown, a 1981 two axle 35' model with the Detroit 671 with the optional turbo, my son Perry did some of the fabrication and welding to mount the tank, fastened to two cross member between the frame rails and the outer body framework. This worked very well and I decided to replicate that setup again.
There are a couple differences between the two installations, first being that we bolted the inner mounting brackets to the cross members instead of welding to them, and second, the drain end is towards the front instead of to the rear. Bolting the support brackets to the cross members was done so that all of the tank mounts could be removed if needed to work on the transmission of the bus. Placing the drain end forward makes it easier to operate the gate valve and connect the waste hose to the tank.

Before any of the effort to install the outside power connections, the holding tank and the propane tank, it was necessary to make the opening for a third right side hatch like the two already there. We started by drilling holes for each of the corners, to later use a hole saw to make the corners. Using a hole saw all four corners were cut. Using a hand grinder with a cutting wheel, all of the sides of the opening were cut. Being aluminum it wasn't too bad to do the cutting, although using the battery powered grinder made for quickly dead batteries. The opening edges were cleaned up using a hand grinder and later a file.

The mounts consist of two rectangular frames made from 1" x 1" x .120 steel, two inner brackets that connect the tank mounts to the cross-members and two outer mount points that secure the framework to the frame of the outer body of the Crown.

First the two rectangular frames were cut with 45 degree angles for the corners. Both frames are sized to the outer dimensions of the mounting flange of the tank. The two frames were the same size and to be mounted one below and one above the mounting flange of the tank. (see photos)

Since the bus is located in a storage yard on a concrete pad about six miles from the house, after MIG welding them together at the corners and grinding the welds a little, we brought them to the house and match drilled them with 5/16" holes using a vertical mill with a digital readout. After bringing them back to the bus we then placed the tank in between the frames and match drilled the tank's flange to the frames. (the mill was used because drilling the holes by hand with a hand electric drill would take forever)

(see photos)

For one half of the outer mounts, steel plates were cut and MIG welded to the lower frame that goes under the flange. The tank and frames were temporarily assembled.

Using a motorcycle jack and wood blocks, the tank and frames were positioned under the bus as close as we could to the intended position, for placement of the outer mounts. The mounting plates were match drilled to the tank's lower frame and temporarily bolted together.

Having satisfied ourselves that the tank was placed how and where we wanted it (we is my brother and I), I tack welded the outer mounting brackets to the side body framework of the Crown. We removed the frames from under the bus to weld the outer mounts the rest of the way. Before any welding was done, the outer body framework was prepped for welding by using a hand grinder with a flapwheel to remove the undercoating and provide a clean surface. Brakeclean was also used to complete surface prep. The steel plates used for the mounts was also touched up with the flapwheel and more Brakeclean. The outer mounts were then MIG welded in place. The outer body framework is thick enough to weld on using a MIG welder.
(see pictures)

Two inner mounts were fabricated, sizing there component parts for length and placement using the tank frames and clamping the various pieces where they were to be used. The inner mount brackets were fabricated using 1" x 2" x .120 steel, and 1/8" steel plate.

Even through the steel used for the inner mounting brackets is new, we still touched the areas to be welded with a flapwheel and Brakeclean. Both the inner mounting brackets are different from each other as the rearmost edge of the tank frame almost lines up to the rear cross-member and the front is some distance back from the front cross-member. With the pieces cut using a band saw and clamped in a vice, I welded all of the pieces together for each mount bracket. Since the front inner mounting bracket requires a 90 degree turn, the connected was gusseted for strength.

With all parts for the tank mounts fabricated, all were thoroughly cleaned with Brakeclean and painted with white Rustolium rattle can paint. The inner mount brackets were installed to the cross members. Note: we matched drilled the brackets to the cross-members and took extra precautions for the hoses and wiring mounted to the forward side of the front cross-member so as to not drill through them and cause ourselves much grief.
(see pictures)

The bolt holes where the inner mounting brackets connect to the tank's frames were match drilled. A total of two additional mounting bolt holes were match drilled in the outer mounts for additional strength.

I realize that some may think that I am over engineering this tank mount but remember how much weight can be inside the holding tank (7lbs x 40 gallons = 280 lbs + the weight of the tank and frames and brackets)

After all of this we removed the tank and frames again, to install the propane tank. The inner tanks mounting brackets were left installed as they clear the propane tank.

The propane tank holds about 24 gallons of propane, being empty it wasn't too heavy.

The propane tank has two outside mount points on its top and two inside mounts to fasten it to a bulkhead or wall in back. Since we are mounting it to the floor of the bus, two mounting brackets bolt to the tank's wall mount tabs and provide two mount points facing up to the floor.

After cleanup of the outside of the tank and application of more Rustolium rattle can paint to it. We jacked it into position using the motorcycle jack and wood blocks. After adjusting the tank's position to where we wanted it, we used the Rustolium paint to spray four markers onto the bottom side of the Crown floor. After removal of the tank we drilled four holes through the floor to mount the tank. We then jacked up the tank into position and installed four through hole bolts and two nuts (with washers) (the outer tank mounts have large nut plates welded in place)
With everything tightened up, the propane tank was mounted. (see pictures)

We next assembled the upper and lower mounting frames to the holding tank, placed it under the bus, raising the inner side into the inner mounting brackets and pulled the tank and frames into place to bolt the outer mounts together. The bolts were installed but not tightened, to allow for adjustments. The inner mount bolts were installed, and all bolts tightened up. The Holding tank is now installed. (see pictures)

The first drain plumbing:
With the holding tank in place, it was time to install the drain plumbing for the toilet.
RV toilets are different than house toilets in a couple respects:
1) They are designed for a low pressure water supply.
2) They do not have the trap like a house toilet, but a a straight shot down the hole.

Because of this one should plumb RV toilets with as little resistance to good flow, as possible. Placement of the toilet is based on clearance from planned walls for the "water closet" and distance from the bathroom sink.

This I had planned out during the cold months and had designed the layout of the Water Closet. Following my guidelines from the design exercise, and the installation instructions, I marked X marks the spot and, using the hole saw, made a large hole through the floor of the Crown. For those dying to know, the wood floor of a Crown is three layers of wood, with the upper and lowest layers in plywood, and the middle "pressed sawdust". There is also a 1/8" thick layer of rubber flooring glued on top. The pictures show that under the floor on the right side of the bus along side the transmission is starting to look kind of busy, but almost all of the installations underfloor are done. The total thickness is 1 1/2". The three layers of wood are not glued together.

The plumbing parts picked were a matter of trial and error figuring out from the pile of parts picked up at Home Depot and Diamond Home improvement. The goals were twofold, the least resistance to flow, and a match-up at the toilet flange and the top of the holding tank.

The parts for the drain pipe were assembled with the glue (actually a mix of dissolved ABS plastic and solvent). The location for the 3" flange was determined, and hole cut with the hole saw. The flange was glued in place and connected to the plumbing through a rubber coupling with two hose clamps. Remember it is important in your design to make all tanks and such removable at a later time. This was done with the first Crown and worked well with no leaks.
(see pictures)

The next post covers the installation of the new hatch cover.

flattracker 09-09-2020 05:24 AM

The Conversion of my 86 Crown Supercoach
4 Attachment(s)
Here are some additional photos

flattracker 09-14-2020 04:03 AM

The Conversion of my 86 Crown Supercoach
5 Attachment(s)
This is another post in my conversion of my 1986 Crown Supercoach. In this post I document the effort to fabricate and install a new hatch to cover the opening we made to provide access to the Propane tank, external power connection, and external water connection to the bus.

I made the decision to not obstruct access to the engine, and also install the holding tank, and propane tank so that they could be removed for access to the transmission if repair is ever needed.

I designed the conversion so that when outside power, water and sewer are connected, that the access cover could be closed and one would not see these connections.

To that end we cut and opening that is the same size as the ones for the spare tire bay, and the engine bay.

We measured the existing hatch for the engine bay and found that it is 48" x 24" x .100". Aluminum is available in .100" thickness, but where I live one has to purchase an entire 4' x 8' sheet. The metal is special order here,and I ordered the whole sheet, and requested two pieces be cut from the sheet, one being 24" x 48", and a second 48" x 5 1/4". The metal was cut in a shear, and the resulting pieces delivered to the storage yard where I keep the bus.

I also ordered a piano hinge 3" wide, stainless steel, 1/4" thick pin. I also requested that it have a 270 degree range, from closed to fully open. I could only order the hinge in 72" lengths. I got the hinge from Fastenall.

Next came the work to bend the hinge to the profile used by Crown. I went to all the places in Klamath FalIs that have a sheet metal brake, and none could duplicate the profile used by Crown for that piece. This piece is where crown mounted the latches to hold the hatch closed. Ultimately I went to a friend at the Airport at Lakeview, Or. who has a 4' wide sheetmetal brake and was willing to let me use it to bend the aluminum. The Crown hatches have a piece of aluminum mounted at the lower edge, and we tried to duplicate that. What we found was that we could bend all but the last bend, as the metal we were attempting to bend got in the way. WE did make the first three bends. The piano hinge requires two bends, and we were able to make those. Our bends were not as crisp as the one made by crown, but the results were usable.
I drilled 5 holes through the stainless steel hinge, and then match drilled holes in the aluminum plate. (see pictures)

I riveted the hinge to the aluminum plate using 1/4" pop rivets. (see pictures)
I drilled holes through the hinge in preparation to mounting the new hatch to the bus.

Using Gorilla tape, I temp mounted the hatch to the side of the bus in order to match drill mounting holes in the bus. I drilled the center hole first and temporarily installed a 1/4 - 20 bolt and nut to hold the hatch in place. This makes it easier to match the outer holes and fasten them later. Ultimately I match drilled a number of holes through the hinge and the bus body, while keeping the hatch as close a position match as the ones Crown installed. For the time being the hinge is bolted to the bus body.
Now having the hatch attached to the bus, next came the mounts for the Crown latches. In my case I still had an original Crown hatch from the parts bus of years ago. I did not re-use the hatch from the 73 Crown parts bus because the hatches from that bus are smaller in length and height. I decided that it wasn't necessary for the latch mounting bracket we bent to run the full length of the hatch (actually near full length).
I cut two lengths of the bracket at 5 1/2" long. I then cut the extra metal from the bracket, checked fit. All would fit the way I had hoped.

I drilled two holes about 1/2" from the lower edge of the panel and match drilled two holes in each latch mount bracket. After pop riveting both brackets, fitting the original Crown latches was next. On the original hatch from 1973, the latch assembly was screwed to the aluminum panel with genuine "Crown screws", so those were unscrewed. Placing the hinge on the upper ledge of the mounting brackets (when the hatch is opened), allowed perfect alignment with the metal ledge of the lower body framework. I marked the location of the latch and its mounting holes, and subsequently drilled the mounting holes through the mounting bracket. After temporarily bolting the latch to the bracket, I drilled a pilot hole through the bracket and the hatch using the square hole through the latch. After removing the latch, 1/2" holes were drilled through both the bracket, and hatch panel. I again bolted the latch to the mounting bracket using two washers just like Crown did originally. I then performed a fit check to latch the hatch. It worked but needed additional mounting so a 5 1/2" length of of 1 /1/2" aluminum angle metal was added to the lower side (with hatch open) of the mounting bracket. This connected the unconnected side of the bracket to the hatch to the panel. (see picture)

The same operations were performed on the second mount and latch. A fit check was performed latching both ends of the hatch, and all worked quite well. Two extra rivets were added between the mounting bracket and the hatch panel for strength.

The hatch now closes and latches just right. (see picture) One last step is mounting the chain that connects between the hatch panel and the ring mounted to the side of the bus. The original hatch panel still had the chain attached so I removed it from the original panel and match drilled two mounting holes through the new hatch panel, and attached the chain. The chain from the old hatch panel was right at twice as long as the ones on the later Crowns so I shortened it. All thats left is fabrication of a body mounted ring to hook the chain on to provide a means to hold the hatch open when needed.

At this point, after fabrication and installation of the retaining ring I am about as far as I can go under the bus before I install some unistrut inside to frame up walls.

Yes I did say Unistrut. When I converted the previous Crown I used Unistrut to frame up walls and counters. This worked very well. I am more comfortable cutting and welding steel than I am doing woodworking. Plus it is very strong, doesn't squeak going down the road, and there is every kind of imaginable bracket made to mount things to unistrut. Once the plating is removed using a grinder, it is easily welded.

My next task is to re-produce the template I made and used to cut the Unistrut to fit inside the Crowns body. I will detail how I do that in my next posting.

flattracker 10-19-2020 10:09 PM

The conversion of my 86 Crown Supercoach
1 Attachment(s)
In my previous post I mentioned I would post about making a template for cutting the unistrut to be used in construction of the walls in the interior of the bus. To that end I came up with an approach to capture the profile I needed to cut when matching the strut to the sides of the interior. The first picture is of what I did on my first conversion of the 1981 Crown. As one can see the Unistrut is mounted against the side of the bus

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