Buying & Building a Medium Ambulance into an RV – The FAM-BULANCE

[rlrenz]

Interesting how some decisions are "made" for us, huh? GREAT deal on those parts! And no gas can hassles!

That's the kind of decision that can suddenly happen when you don't expect it. Onan's parts have never been cheap, and after they became part of Cummins, I don't think there were any price reductions. When I priced out the conversion, I figured that gasoline wasn't all bad - I had thought about a built-in tank, but then I'd have the problem of elderly gas unless I used it all, which pointed to using a system based on 5-gallon gas cans -- I could remove the excess easily and use it up in the lawn tractor / snowblower / whatever. Gasoline and propane both have the same advantage over diesel - a diesel likes to be loaded to about 75% or so, while a gasoline / propane generator is happy anywhere between no load / full load. Even through the Onan generator has a screwdriver-operated drain valve on the carb, it still takes a bit of fiddling to store versus just closing a valve for propane.

So, now I'm back in the propane bottle lift design / build project. The design is already doped out - it is based on a 250 Lb capacity WWII surplus hoist, plus a 250 Lb capacity trolley I found. The trolley will work perfectly on a 3" aluminum I beam.

I've also looked at several designs for commercial O2 bottle lifts that are available for ambulances - the lifts themselves have some nice design features, but the prices definitely are geared to someone who doesn't panic at the cost of a brand new ambulance. One design uses a linear actuator to lift a bottle into an ambulance, and another uses a boat winch on a handtruck with a sliding segment to lift a bottle to ambulance loading height - that design has possibilities, except the handtruck has to be stored somewhere on board.

 

[rlrenz]

This weekend, I reinforced my belief that a "simple project" can turn into a big, ugly, PITA project. The front cabinet on the passenger's side (cabinet #5) had a jog in the floor so the cabinet could be deeper above the jog. The jog in the floor meant that if I stuffed a table into the cabinet, it would be supported by the anti-fallout strap and one corner. I decided that the jog should become a shelf so the bottom would be flat and thus easier to use.

Simple project- yes?

I had to remove the existing vertical partition, saw off the bottom 14", and reinstall it. Except, the blasted partition must have been about the first thing installed in the ambulance. It couldn't be removed due to the interferences from the door framing. It had a flange on the top, down the back, and on the bottom that kept it nice and stiff, so there was no hope of bending it a little. I finally dug deep into my tool box and got out an aircraft panel saw. This is a 2" circular saw that sails through sheet aluminum, and it let me whack off about 10" from the bottom of the partition. The partition was then removed.

Cutting the partition was easy - a few minutes in the shop and it was done. Then I hoisted the partition back into place, and bolted it back into place - did I mention that the original self-tapping 10-32 machine screws resulted in damaged threads in the cabinet so they all had to be replaced? I was going to use Riv-Nuts, but the cabinet construction made that impossible, so I retapped the holes to 1/4-20. The partition was finally back in place.





Next, I slid the new shelf into place, drilled bolt holes, and installed new bolts, including self-tapping 10-32 machine screws where there was only one side access. Using a screwdriver on the side of a 6" wide partition area at arm's length is one of those fun tasks that I'll remember for many days.

The finished job - a royal PITA, but the end result makes it all (mostly) worth the work


In addition to my aircraft panel saw, I have two other very useful aircraft left-overs - the first is a 2500 RPM 1/4" air drill that can punch a hole through 1/8 aluminum in a split second, and the other is a right angle aircraft drill that takes 1/4-28 threaded shank bits and drills a hole equally fast. It does an excellent job of getting into places that you can only see with a mirror.


Finally, only 1.5 days after I started, the job was done.

 

[patoz]

I guess the future is now--- The only parts that make up the propane capability are a propane carb, a propane demand regulator, and a propane solenoid valve. The regulator alone carries an Onan price of $319. I was prowling through EBAY this morning, and decided to check some part numbers - I found the regulator with carb for $90, and the solenoid valve with piping/etc for $85. I bought them, which also decided on the fuel of choice for the generator.<br>
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The regulator has a priming feature that consists of a solenoid valve on the regulator that connects to the starter, so when the starter is running, the regulator gives the engine a positive shot of propane. The propane shut-off solenoid valve (normally closed) connects in place of the fuel pump. I'm not too worried about the brackets/etc that mount everything - I can either come up with an alternate, or track down a dead unit at an RV repair shop and just buy the brackets.<br>
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So, I'm back to installing a 100 Lb propane tank in my old oxygen cabinet. Right now,t he cabinet has one vent in case any O2 is vented, and I'll add another at the bottom of the cabinet door since propane is heavier than air. I might even add some holes in the cabinet floor for even more ventilation if necessary.

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At first, I was going to say stay with gas because if the availability everywhere, even in the case of a disaster (which is one of my priorities living in Pensacola, Florida), but you have now talked me into the tri-fuel route. Since mine will be probably go long intervals between needing to run on generator, I'm thinking propane is the way to go with gas as the backup fuel. Probably safer too, since I'm thinking of mounting it in the left front compartment (#2).

I found a kit for the Honda EU3000is which you can see here, and it's similar to the Motorsnorkle one you found first, but uses a modified replacement carburetor.

Is the one you found on eBay a one-of-a-kind thing, or is that a product they sell on a regular basis. If so, can you post a link for it? Thanks...

 

[rlrenz]

I was able to find actual Onan parts - it helped that I had the part numbers, so I just searched for that number, plus there are thousands of the Onan RV generators out there. I'm willing to bet that all the pieces are probably off-the-shelf from someone out there - at least the regulator and the solenoid valve, and someone could probably modify a used gasoline carb into a propane carb with a drill and pipe tap. For what I'm planning, propane will work well, but living in FL, I can see why being able to handle gasoline and propane might be necessary.

At least one of the tri-fuel kits uses a filler piece between some of the carb's gaskets to meter in natural gas / propane. That would probably do the best job for you.

 

[patoz]

At least one of the tri-fuel kits uses a filler piece between some of the carb's gaskets to meter in natural gas / propane. That would probably do the best job for you.

Yep, I agree and it looks like it's the easiest to install also. And according to their video, to change fuels you just shut one off and turn the other one on.

 

[rlrenz]

WAAAY off topic - but I had to show what you can find out there. I was asked if I could help a neighbor fix his trolling motor - he commented that it wasn't working very well compared to when it was first installed. I pulled the power cable from it, and this is what I found:

This was actually a splice. Electrical continuity was assured by several wraps of electrical tape.


This terminal looks like it's only claim to fame was being selected to match the bolt size. Whatever was used to crimp it didn't do much of a job.


I gave him a list of what to buy, and as soon as he gets the pieces, I'll reassemble it a bit more thoroughly than the last installer did.

I'm amazed that it even worked at all.

Now I REALLY appreciate the wiring in my ambulance....

 

[Gemini]

Quality engineering!

 

[Gatsma]

It's ALWAYS nice to know there ARE some who know LESS than we do; will wonders never cease?

 

[patoz]

Being Firefighter for 35 years, that looks pretty good compared to some of the DIY electrical repairs or modifications we have run across during building inspections. Most people just don't understand the concept of electricity.

Since you're going off topic for a minute, and given your versatile background, I would like to ask you a question I can't seem to find an answer for.

I have a 1993 E350 Wheeled Coach Ambulance that I've removed the cab, engine, transmission, and front end from it. It had 262,000 miles on it, three previous owners, and was worn slap out. I intend to add a tongue to it and make a heavy duty camper trailer out of it.

I need to add electric/hydraulic brakes to it, and am trying to use the existing Ford rear drum brakes. In order to purchase the correct size actuator, I need to know what the operating range of this Ford system (rear) is in psi. I have spent all day on the net trying to find the answer, but no luck.

Do you know by any chance?

 

[rlrenz]

There are many people out there who probably have to try both directions in order to unscrew a lightbulb. I once saw someone who had very carefully stapled zip cord (lamp cord) to wire his cabin - I still wonder what happened when he plugged it into his generator. I think differently - when I rebuild my neighbor's trolling motor, the terminals will be crimped with a hydraulic lugger, and sealed with heavy duty adhesive heat shrink. I used to have a Pico pneumatic aircraft crimper that I passed on to an ambulance electrician I know who uses it for the Anderson connectors on Vanner inverters - I figured I didn't need both the Pico and the hydraulic crimper.

All I can suggest is trying to track down a chassis service manual - the brake section MIGHT say something. You might also see if Ford has a training center anywhere nearby - one of their instructors might be able to give you some help. It might be a whole lot easier to install trailer electric brakes because their braking force can be adjusted very easily, and the installation would be a whole lot cleaner.

 

[patoz]

All I can suggest is trying to track down a chassis service manual - the brake section MIGHT say something. You might also see if Ford has a training center anywhere nearby - one of their instructors might be able to give you some help. It might be a whole lot easier to install trailer electric brakes because their braking force can be adjusted very easily, and the installation would be a whole lot cleaner.

I use terminals and butt splices with the heavy duty adhesive heat shrink on everything I build. It boils down to 'pay now or pay twice as much later' and you will pay.

I talked to a very reputable local boat trailer builder today and he is checking on it for me, but I'm starting to think trying to use the existing Ford parts to save a few bucks may not be the answer (same concept as I just mentioned). When I call him back tomorrow, I'm going to get a price on replacing the brakes as you suggest, and also on replacing the entire axle assembly.

 

[rlrenz]

And fixing a screw-up never happens on a nice sunny day in your driveway when you have all the time in the world...

 

[Gemini]

Being Firefighter for 35 years, that looks pretty good compared to some of the DIY electrical repairs or modifications we have run across during building inspections. Most people just don't understand the concept of electricity.

Then there is the other side of the coin ... when I upgraded the electrical service entrance into my house the building inspector came to review prior to service reconnection. He spent 2 minutes looking at it then turned to me and asked "Are you an engineer?". I replied, "Yes, why do you ask?". His reply, "Because you have overbuilt the solution.". "Is that a problem?", I asked. "No," he said, "I wish more people would do what you did here."

We then spent the next 30 minutes discussing design aspects to prevent ground loops ( I hate ground loops, buggers up the HF/VHF radios...) ...

 

[rlrenz]

Then there is the other side of the coin ... when I upgraded the electrical service entrance into my house the building inspector came to review prior to service reconnection. He spent 2 minutes looking at it then turned to me and asked "Are you an engineer?". I replied, "Yes, why do you ask?". His reply, "Because you have overbuilt the solution.". "Is that a problem?", I asked. "No," he said, "I wish more people would do what you did here."

We then spent the next 30 minutes discussing design aspects to prevent ground loops ( I hate ground loops, buggers up the HF/VHF radios...) ...

I used to run a vibration test lab where ground loops were major headaches - when I saw a 60 Hz resonance on the controller, I knew that there was a spare ground somewhere, and then I'd get to chase it down. Sometimes very simple, most times not so simple.

People have to realize that the electrical code is a minimum set of requirements. When a job is estimated, though, the default is always what the code requires. A Square D panel can be an extra with some contractors. Me? All Square D here at home, and Square D or Allen Bradley in my shop.

The ambulance is getting Blue Sea electrical gear over Square D - it does things you can't do (easily or at all) with Square D, and it's made for a moving environment.

 

[rlrenz]

I'm still double-thinking myself. I have everything needed to set the rig up for propane, but there is still a strong argument for gasoline - available 24x7 is probably the biggest argument, plus a 5 gallon can is a lot lighter than a 170 Lb (GW) propane bottle. If I buy the high grade no-ethanol gas, any fuel I don't use for the generator can be stored for the next trip with no problem, and even used in my lawn tractor. I have room in the future-generator cabinet for the generator, a starting battery, a portable boat gas tank, and 3-4 5 gallon gas cans. If I go propane, I have to clean out the adjacent cabinet to hold a propane bottle. The money I've spent for the propane conversion package can be recovered by selling the parts to someone else.

I tunneled through the internet, and about as many people swear at as seem to swear by one or the other. I'm not planning to stay off the grid somewhere for weeks at a time - just for a day or so on my own, otherwise somewhere with access to a ground power connection.

Every time I toss the coin, I get a different answer - what are your thoughts? Propane -- gasoline? Leave it as gasoline for now, with maybe propane in the future?

FYI, here's a photo of a packaged system that looks fairly logical (I'd probably be a little fussier, though, but is certainly says KISS: